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Kiyofumi Kurumisawa
Faculty of Engineering　Sustainable Resources Engineering　Resources Engineering
Associate Professor
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Last Updated :2024/05/09

Researcher Profile and Settings

Affiliation

  • Faculty of Engineering　Sustainable Resources Engineering　Resources Engineering

Job Title

  • Associate Professor

Degree

  • Doctor of Engineering（Tokyo Institute of Technology）

URL

J-Global ID

Research Interests

  • Geopolymer   セメント硬化体   反射電子像   物質移動   粗大空隙   電気伝導率   水和反応率   自己相関関数   エネルギー分散型X線分析   セメントペースト   塩分浸透性   弾性係数   構成化合物量   拡散係数   溶脱   高炉スラグ   XRDリートベルト法   相平衡   拡散   界面性状   空隙   元素分布像   イオン   3次元イメージ   熱力学相平衡   動弾性係数   混和材   空間分布   空隙構造   ２H NMR   リートベルト法   NMR   durability   microstructure   concrete   cement   

Research Areas

  • Social infrastructure (civil Engineering, architecture, disaster prevention) / Building structures and materials
  • Social infrastructure (civil Engineering, architecture, disaster prevention) / Civil engineering (materials, implementation, construction management)

Educational Organization

Academic & Professional Experience

  • 2009 - 2013 Hokkaido University
  • 2005 - 北海道大学大学院工学研究科 研究員
  • 2005 - Researcher

Education

  •        - 2003  Tokyo Institute of Technology  Interdisciplinary Science and Engineering
  •        - 2003  Tokyo Institute of Technology  Graduate School, Division of Integrated Science and Engineering

Association Memberships

  • JAPAN CONCRETE INSTITUTE   日本建築学会   資源・素材学会   

Research Activities

Published Papers

  • Qi Zhai, Kiyofumi Kurumisawa, Juhyuk Moon, In-Hee Hwang
    Journal of Cleaner Production 2024/05
  • Qi Zhai, Kiyofumi Kurumisawa, Juhyuk Moon
    Construction and Building Materials 408 0950-0618 2023/12 [Refereed]
     
    The initial reactivity and strength development of blast furnace slag cement (BFSC) are crucial factors that increase its utilization. Therefore, it is important to select the most suitable accelerator. In this study, the impact of four accelerators, namely sodium sulfate (Na2SO4), calcium nitrite (Ca(NO2)2), triethanolamine (TEA), and diethanolisopropanolamine (DEIPA), on the hydration and strength development of BFSC at curing temperatures of 5 and 20 °C was investigated. Isothermal calorimetry, X-ray diffraction (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP) were conducted. The results revealed that Na2SO4 effectively enhanced early age strength by accelerating the hydration of the clinker and slag. Ca(NO2)2 is sensitive to temperature changes. At 20 °C, Ca(NO2)2 promoted the reaction of the aluminates and slag in the initial stage. However, the presence of slag inhibited clinker hydration, and the addition of Ca(NO2)2 exacerbated this effect, resulting in reduced strength at 5 °C. Indeed, the use of TEA and DEIPA at 0.02 % at 5 °C is not recommended. Complex interactions between TEA and Ca2+ may inhibit the formation of calcium hydroxide crystals, further inhibiting aluminate hydration. This may lead to low strength development at low curing temperatures such as 5 °C.
  • Yukun Kong, Masaji Kato, Kiyofumi Kurumisawa
    Journal of Advanced Concrete Technology 21 (8) 573 - 595 1346-8014 2023/08 [Refereed]
     
    Alkali-activated materials (AAMs) have been extensively studied due to their high performance and low carbon emissions. However, the long-term durability of AAMs remains a major concern, which is closely related to their microstructures and pore networks. X-ray computed tomography (CT) has emerged as a powerful non-destructive technique for three-dimensional microstructural analysis in the field of civil engineering. While CT has been widely used to investigate cement-based materials, its application to AAMs is still limited. In this review, we provide a comprehensive summary of the background information and applications of CT in AAM research, focusing on pore structure analysis, phase identification, degradation analysis, fiber reinforcement, temporal evolution and simulations. Furthermore, the current challenges and future perspectives are also discussed.
  • Y.K. Kong, Kiyofumi Kurumisawa
    Case Studies in Construction Materials 18 2214-5095 2023/07 [Refereed]
     
    Alkali-activated materials (AAMs) have been extensively studied for their superior performance and eco-friendliness. While previous researches have primarily focused on the hardened properties of AAMs, the assessment of their fresh properties has often been overlooked. The preparation process of AAMs involves key factors in mix design that significantly impact their workability. This study comprehensively evaluates the workability of different types of AAMs, analyzing a total of 402 mixtures extracted from 26 individual papers. The examination focuses on key factors in AAM mix design, specifically the precursors, alkali activator, and aggregate phases. Finally, a mathematical model for predicting the workability of AAMs was constructed based on the LightGBM (LGBM) algorithm. In this model, the reactivity of precursors, alkali activator, geopolymer paste volume, superplasticizer content, and aggregate were set as the inputs, and the flowability was set as the output. Additionally, the predictive efficiency of LGBM model was evaluated and compared to the multi-linear regression model. Meantime, a validation experiment for proving its accuracy was also conducted. This study largely advanced the understanding of the workability of AAMs by providing practical guidelines on AAM mix design with high workability and consistency.
  • Zhai Qi, Yibing Zuo, Kiyofumi Kurumisawa, Aoran Lang
    Cement and Concrete Composites 141 0958-9465 2023/05 [Refereed]
     
    The impact of additional activators (sodium sulfate, sodium nitrite, and calcium nitrite) and curing temperature (20 and 35 degrees C) on chloride binding and ingress resistance of ground granulated blast furnace slag activated by Ca (OH)2 was studied using X-ray diffraction, scanning electron microscopy, thermogravimetric and thermodynamic modeling. The outcomes of the study indicated that the difference in the chloride binding capacity at low chloride concentrations was primarily affected by the types of the AFm phase. The solid solution formed between Friedel's salt and various types of AFm phases resulted in a decrease in the chloride binding capacity. At a curing temperature of 35 degrees C, the chloride binding capacity reduced due to the leaching of calcium ions and carbonation induced by the coarse pore structure. It was found that the chloride ingress resistance was significantly related to the leaching of calcium and carbonation, and the denser calcite layer formed at the exposure layer had a positive impact on the chloride ingress resistance.
  • Y.K. Kong, Kiyofumi Kurumisawa
    Journal of Building Engineering 75 2023/05 [Refereed]
     
    Alkali-activated materials (AAMs) are increasingly popular as ecofriendly and sustainable construction materials due to their ability to reduce carbon emissions and utilize industrial byproducts. However, their practical application is currently hindered by variability in their intrinsic properties during the early stages, which affects their handling, placement, and early age performance. This study aims to provide an overview of the fresh properties of AAMs, focusing on workability, rheology, setting behavior, and heat flow. The influence of material composition on the workability and setting of AAMs is presented, and characterization methods for workability, heat flow, and early microstructure are highlighted. The workability of AAMs depends on various factors, including mix design, precursor composition, alkali activator concentration, and aggregate size. AAMs exhibit a fast setting time due to enhanced alkali activation, and the heat release during hydration is influenced by the precursor type and curing temperature. This study discusses the current limitations of fresh AAMs and provides future perspectives for research. To address these limitations, the authors propose data fusion from various experimental results and image-based analysis of the microstructure of fresh AAMs. Overall, this study contributes to a better understanding of AAMs and offers valuable insights for sustainable construction applications.
  • S. H. Chu, K. Kurumisawa, Y. K. Kong
    Engineering Structures 275 0141-0296 2023/01/15 [Refereed]
     
    This paper presents a quantitative analysis of the mechanical performance of ultra-high performance fiber-reinforced concrete (UHPFRC). UHPFRC shows great potential in the construction of the cities of tomorrow. However, establishing empirical formulas by incorporating existing data for the practical engineering design of UHPFRC remains a problem. To advance the understanding of UHPFRC, this paper qualitatively and quantitatively studied UHPFRC with an emphasis on its strength. Utilizing abundant data consisting of 111 different UHPFRC mixtures in literature, the key factors governing the strength of UHPFRC, e.g., the volumetric ratios and types of paste, aggregate, fibers and filler, were identified. Based on the key factors, a robust mathematical model for the strength prediction of UHPFRC was established. In addition, an artificial neural network model was constructed. This study shall provide useful guidelines for the mix design of sustainable and resilient UHPFRC.
  • Y. K. Kong, K. Kurumisawa, S. H. Chu
    Journal of Cleaner Production 377 0959-6526 2022/12/01 [Refereed]
     
    In this study, a comparative life cycle assessment (LCA) approach was adopted to scrutinize the environmental impacts of infilled cementitious composites (ICC) and ultra-high performance concrete (UHPC). UHPC, being prevalent for decades, encounters obstacles in application due to its high binder content, high heat generation, high material cost, and absence of coarse aggregate and macro steel fibers. To break these bottlenecks, ICC is developed based on fiber-particle packing theory, paste volume control and UHPC technology. To facilitate wider applications of ICC, LCA is performed on five categories, i.e., global warming (GWP), ozone depletion (OD), acidification (AP), eutrophication (EP), and photochemical ozone creation (POCP), according to International Organization for Standardization (ISO) 14040 and the Ecoinvent database. The ecological impacts of ICC can be further mitigated using supplementary cementitious materials and filler. A heuristic design of ICC is proposed towards reduced environmental impacts.
  • Y. K. Kong, Kiyofumi Kurumisawa
    CASE STUDIES IN CONSTRUCTION MATERIALS 17 2214-5095 2022/12 [Refereed]
     
    Alkali-activated materials (AAMs) are qualitatively and quantitatively evaluated with an emphasis on the ultimate drying shrinkage. We systematically evaluated AAMs based on the mix design and curing conditions, utilizing a total of 452 AAM mixtures extracted from 44 papers. Finally, a predictive model for the ultimate drying shrinkage of AAMs was constructed using an artificial neural network (ANN) with high accuracy, in which the reactivity of binder, geopolymer paste volume, liquid-to-binder ratio, alkali activator modulus, aggregate volumetric ratio, curing temperature, relative humidity and specimen size were set as inputs. This model shows great generality by compiling various AAM mixtures and is easy-handling without preparation of samples for acquiring specific properties. Moreover, the efficiency of three commonly used models for predicting the drying shrinkage-the Bazant-Baweja model, Gardner and Lockman model, and multi-linear regression model-were evaluated and compared to the proposed ANN model, revealing a better prediction performance of ANN model. This study will advance the understanding of the drying shrinkage behaviors of AAMs and provide practical guidelines for designing AAM mixtures with high durability.
  • Y. K. Kong, S. Ruan, Kiyofumi Kurumisawa
    Journal of Environmental Chemical Engineering 10 (5) 2213-2929 2022/10 [Refereed][Not invited]
     
    In this study, calcined carbonated hydrated cement pastes (HCPs) were used to partially replace ordinary Portland cement (OPC) as a cementitious material. Calcined carbonated HCP can be derived from carbonated HCP after the release of CO2 for the carbon capture, utilization, and storage (CCUS). Calcined carbonated HCP was produced by calcining carbonated HCP at 1000 °C, also used in calcium looping. The crystal phase compositions of the HCP, carbonated HCP, and calcined carbonated HCP were identified. Various hardening and microstructural tests on the composite cement paste mixtures blended with calcined carbonated HCP were performed. The initial results showed that the HCP could sequester CO2, forming various calcium carbonates. After carbonated HCP calcination, the main nanocrystalline phases of calcium silicate hydrate (C-S-H) and calcium carbonate decomposed, forming lime and wollastonite. The 28-day compressive strength of the calcined carbonated HCP-OPC mixtures increased with the replacement ratio up to 20%, owing to the filler effect of wollastonite. The microstructural analysis revealed that the portlandite, C-S-H, and monocarboaluminate phases were formed after hydration. Finally, by recycling demolition waste, this study proposed a technology roadmap for CCUS to achieve this goal, and a life cycle assessment was conducted to evaluate and compare the environmental impacts of producing 1 t of calcined carbonated HCP-OPC mixtures and plain OPC paste.
  • Qi Zhai, Kiyofumi Kurumisawa
    Cement and Concrete Composites 133 0958-9465 2022/10 [Refereed]
     
    This study explores the effects of the cations in sulfates, chlorides, and nitrites on calcium-hydroxide activated blast-furnace slag. Using several methods, it was demonstrated that the activators investigated could improve early strength development. Compared with chlorides and nitrites, the type of sulfate has a significant influence on slag hydration. Compared with K2SO4 and Na2SO4, the promotion of slag hydration in MgSO4, at an early age, is limited due to the precipitation of gypsum and brucite which retard the formation of hydrates and limits hydration kinetics during the initial stage. The high concentration of sulfate ions in the pore solution causes some ettringite to remain, promoting strength development. It was observed that the mechanism of pH increase in K2SO4 and Na2SO4 is due to the synergistic reactions between the sulfates and Ca(OH)2, while the low pH of MgSO4 due to the low solubility of brucite inhibits slag dissolution. The critical pH for promoting slag hydration was determined to be 13.1.
  • Ali Jamshidi, Greg White, Kiyofumi Kurumisawa
    ROAD MATERIALS AND PAVEMENT DESIGN 24 (4) 881 - 918 1468-0629 2022/04 [Refereed]
     
    There is an increasing demand for high strength and more durable materials in the asphalt technology market. In response to the demand, epoxy asphalt mixture (EAM) is one relatively new technology for use as a paving material in flexible pavements. There are various research works carried out on the laboratory and field performance of EAM. However, comprehensive research covering functional and field (F&F) performance of EAM is lacking. The main purpose of this review is to bridge this gap via the analysis of the functional properties of EAM. Consequently, the field performance of EAM in different case studies is reviewed and the serviceability of EAM in various transportation infrastructure is investigated. This paper also reviews the life cycle cost and maintenance of EAM. The major findings indicate that EAM shows superior F&F performance compared to the traditional hot and warm asphalt mixture. Additionally, the use of EAM is beneficial in the structure of pavements in tunnels and on bridge decks. In conclusion, the higher F&F performance of EAM supports the development of better performing pavements for various applications.
  • KURUMISAWA Kiyofumi
    Cement Science and Concrete Technology 一般社団法人 セメント協会 75 (1) 174 - 180 0916-3182 2022/03/31 [Refereed]
     
    The physical properties of the blast furnace slag composite with the inorganic salt were investigated. The compressive strength was initially increased by adding an inorganic salt. The drying shrinkage tended to differ depending on the type of inorganic salt added, and the initial shrinkage with the sulfate-based salts was lower than that without salt. On the other hand, it was shown that the shrinkage increased in the initial stage with nitrite and calcium chloride, but did not increase significantly thereafter. The diffusion coefficient also tended to differ depending on the type of the inorganic salt to which it was added, and the diffusion coefficient of specimen with inorganic salt tended to be higher than that without salt. It was considered that this was because the addition of the inorganic salt produced an aluminate-based hydrate, which reduced the amount of anions such as chloride or iodine adsorbed in specimen. It was shown that the amount of adsorption is the dominant factor on the diffusion performance of blast furnace slag composite.
  • SAKEMOTO Kotone, KATO Masaji, ISHII Yusuke, KURUMISAWA Kiyofumi, NARA Yoshitaka
    Journal of the Society of Materials Science, Japan 公益社団法人 日本材料学会 71 (3) 228 - 234 0514-5163 2022/03/15 [Refereed]
     
    Information on the permeability of materials for radioactive waste disposal in geological repositories is essential. High strength and ultra low permeability concrete (HSULPC) is being considered as a material used to package transuranic (TRU) waste. HSULPC would be reinforced by steel fiber to increase its tensile strength and toughness, but the effect of reinforcing steel fiber on permeability is unclear. Permeability tests need to be highly accurate to determine the hydraulic properties of low permeability materials. In this study, the hydraulic conductivity of HSULPC with steel fiber using the transient pulse method. The hydraulic conductivities of HSULPC with/without steel fiber were determined to be around 10−13 to 10−11 m/s under the confining pressures between 2 and 10 MPa and pore pressure of 1 MPa constant. The results further showed that the permeability of these materials had a hysteretic dependence on the effective confining pressure. There was no remarkable difference of hydraulic conductivity between HSULPC with and without steel fiber. SEM observation revealed that HSULPC with steel fiber has isolated voids to some extent included during mixing of concrete but there are few voids on the interface of steel fiber for water channel. However, due to the higher porosity, the hydraulic conductivity of HSULPC with steel fiber is relatively higher than that without fiber. Still, the permeability of fiber reinforced HSULPC is low enough compared with Horonobe mudstone and Toki granite and would enable it to effectively confine 14C radionuclides in TRU waste.
  • Kotone Sakemoto, Masaji Kato, Yusuke Ishii, Kiyofumi Kurumisawa, Yoshitaka Nara
    Materials Transactions 63 (12) 1639 - 1644 1345-9678 2022 [Refereed]
     
    Information on the water permeability of materials for radioactive waste disposal in geological repositories is essential. High strength and ultra-low permeability concrete (HSULPC) is being considered as a material used to package transuranic (TRU) waste. HSULPC would be reinforced by steel fiber to increase its tensile strength and toughness, but the effect of reinforcing steel fiber on permeability is unclear. Permeability tests need to be highly accurate to determine the hydraulic properties of low permeability materials. In this study, the hydraulic conductivity of HSULPC with steel fiber using the transient pulse method. The hydraulic conductivities of HSULPC with/without steel fiber were determined to be around 10113 to 10111 m/s under the confining pressures between 2 and 10 MPa and pore pressure of 1 MPa constant. The results further showed that the permeability of these materials had a hysteretic dependence on the effective confining pressure. There was no remarkable difference of hydraulic conductivity between HSULPC with and without steel fiber. SEM observation revealed that HSULPC with steel fiber has isolated voids to some extent included during mixing of concrete but there are few voids on the interface of steel fiber for water channel. However, due to the higher porosity, the hydraulic conductivity of HSULPC with steel fiber is relatively higher than that without fiber. Still, the permeability of fiber reinforced HSULPC is low enough compared with Horonobe mudstone and Toki granite and would enable it to
  • Kong, Y., Song, Y., Weng, Y., Kurumisawa, K., Yan, D., Zhou, X., Wang, S., Ruan, S.
    Greenhouse Gases: Science and Technology 12 (2) 249 - 262 2152-3878 2022 [Refereed]
     
    Carbonated cement pastes (CCP) can be used as stable carbon storage. In this work, CCP were systematically investigated as supplementary cementitious materials (SCMs)-like components used in ordinary Portland cement (OPC) paste. The fully hydrated cement pastes were pulverized into powders and then exposed to different CO2 pressure conditions (i.e., 1.0, 2.0 and 2.5 MPa) for 24 h. These CCP powders were then mixed with OPC to form a new binder. Various fresh, hardened and microstructural properties of CCP powders and the mixtures were investigated. Initial results show that the CO2 sequestration level of CCP increased with the growth of CO2 pressure, and albeit a pozzolanic reaction occurred inside the mixture, the relatively higher water demand due to the use of 30% replacement of CCP led to the inferior workability and compressive strength than the control group. Finally, a conceptual model relating to the CCP-OPC paste was proposed, facilitating the comprehension of the hydration behaviours of CCP-OPC paste. (c) 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.
  • Zhai, Q., Kurumisawa, K.
    Construction and Building Materials 338 0950-0618 2022 [Refereed]
     
    This study investigated in detail the coupling effects of curing temperatures (5, 20, and 35 degrees C) and additional activators (Na2SO4, Ca(NO2)(2), NaCl, and Na2S2O3) on Ca(OH)(2)-activated granulated blast-furnace slag (GGBFS). The results show that the early strengths, hydration degree and microstructure of samples depend strongly on the curing temperature and the nature of activators. Activators influence considerably the initial pore solution composition and pH value, while low-pH values and high-Ca2+ activity suppress the dissolution of Ca(OH)(2) and the reaction of GGBFS. Elevated temperatures mainly accelerate the hydration of GGBFS in all samples at early age. However, owing to the cross-over effect, there is a negative effect on the properties of the samples with added sodium salts in the middle and late stages of hydration. For samples in which Ca(NO2)(2) was added, the early hydration is low owing to the common ion effect, and high temperature plays a facilitating role instead. Furthermore, the apparent activation energy of GGBFS hydration was also determined to explain the observation. Results show that the sample in which the additional activator was added was influenced considerably by the curing temperature, while samples in which Ca(NO2)(2) was added were more sensitive to curing temperature changes.
  • Y. K. Kong, Y. Song, K. Kurumisawa, T. Wang, D. Yan, Q. Zeng, X. Zhou, S. Ruan
    Journal of CO2 Utilization 55 2212-9820 2022/01 [Refereed]
     
    In this study, the feasibility of using hydrated cement paste (HCP) as a CO2 sponge was investigated. The grounded HCP were carbonated, calcined and re-carbonated to investigate the potential of CO2 transportation through the use of HCP. Facilitated by the microstructural analysis, the capacity of CO2 sequestration and release via HCP, as well as the carbonation phases formed within the carbonated/calcined/recarbonated cement paste, were investigated. The initial results indicate that HCP could sequestrate CO2 to become carbonated cement paste (HCPcarbonated) with a high CO2 capture ratio, where a number of carbonates formed. After the calcination of HCPcarbonated, the calcined carbonated cement paste (HCPcalcined) was produced and some new phases formed with a large release amount of CO2. In terms of the re-carbonation process, moisture within the HCPcalcined played an important role concerning its re-carbonation efficiency. Finally, by means ofHCP, this research innovatively proposed a new concept to effectively transport CO2, that is, a CO2 sponge, as well as a technology roadmap, to achieve this goal.
  • Qi Zhai, Kiyofumi Kurumisawa
    Cement and Concrete Composites 124 0958-9465 2021/11 [Refereed]
     
    The early effects of three accelerators on a Ca(OH)2 activated ground granulated blast-furnace slag binder at low curing temperatures are discussed. The compressive strength, hydration kinetics, hydration products, and microstructures were investigated by isothermal calorimetry, X-ray diffraction, mercury intrusion porosimetry, scanning electron microscopy, and nuclear magnetic resonance. Results show that accelerators continue to promote the strength development of pastes in the early stage during low-temperature curing, especially with sodium sulfate, which exhibits a higher strength and hydration degree in the early stage. However, accelerators cannot effectively improve the pore structure at low-temperature curing, which severely restricts the development of strength, compared with that at 20 °C. Furthermore, a good correlation was found between the initial strength development and the limit equivalent ionic conductivity (LEIC), suggesting that LEIC influences the reaction acceleration of blast-furnace slag at an early age.
  • Ali Jamshidi, Greg White, Kiyofumi Kurumisawa
    ROAD MATERIALS AND PAVEMENT DESIGN 23 (9) 1957 - 1980 1468-0629 2021/08 [Refereed]
     
    The asphalt industry is aiming to produce high-quality materials and efficient technologies for pavement construction. One such technology that attracts attention is epoxy asphalt. This paper discussed the concepts, theories and engineering properties of epoxy asphalt technology and products. As the initial step, the chemical structure of epoxy materials was explained. Then principles of epoxy asphalt technology were discussed. Subsequently, the rheological characteristics of epoxy asphalt binder (EAB) were characterised. Engineering properties of an epoxy asphalt mixture (EAM) were then evaluated. The results indicated that EAB has better rheological properties than the traditional modified and net asphalts. Moreover, the results showed that superior structural performance of EAM compared with the traditional hot and warm mixtures. However, recyclability, initial strength and total cost of pavement construction remain matters of concern.
  • Thiloththama H. K. Nawarathna, Kazunori Nakashima, Tetsuya Kawabe, Wilson Mwandira, Kiyofumi Kurumisawa, Satoru Kawasaki
    ACS SUSTAINABLE CHEMISTRY & ENGINEERING 9 (34) 11493 - 11502 2168-0485 2021/08 [Refereed]
     
    Biomineralization is a process of mineral formation in living organisms. Compared with nonbiogenic minerals, biominerals can be defined as organic-inorganic hybrid materials that have excellent physical and optical properties. In the current study, an artificial protein mimicking the outer shell of crayfish, composed of CaCO3, chitin, and proteins, was developed to facilitate organic-inorganic hybrid material formation by precipitation of calcium carbonate on the chitin matrix. The fusion protein (CaBP-ChBD) was constructed by introducing a short-sequence calcite-binding peptide (CaBP) into the chitin-binding domain (ChBD). Calcium carbonate precipitation experiments by enzymatic urea hydrolysis revealed that a significant increase in the CaCO3 formation was achieved by adding CaBP-ChBD. Also, CaCO3 was efficiently deposited on chitin particles decorated with CaBP-ChBD. Most interestingly, CaBP-ChBD would improve the performance in sand solidification more efficiently and sustainably in the process of biocementation technique. The developed recombinant protein could be used for the sustainable production of organic-inorganic green materials for engineering applications.
  • Kiyofumi Kurumisawa, Hiroaki Omatu, Yuta Yamashina
    Materials and Structures 54 (4) 1359-5997 2021/08 [Refereed]
     
    A basic investigation into whether a geopolymer can be utilized as a part of an artificial barrier during radioactive waste disposal was conducted in this study. Geopolymers are comprised primarily alumina and silica, and they exhibit negligible leaching owing to the absence of calcium. Studies on geopolymers are limited compared to those on other cementitious materials because the physical characteristics of geopolymers vary with the production conditions. In this work, metakaolin based geopolymers were prepared, and their diffusion performance was analyzed. The results indicate that the diffusivity of cesium in a geopolymer is affected by the type of alkali activator. Sodium-activated geopolymers had higher cesium adsorption capacity than potassium-activated geopolymers. The cesium adsorption capacity also had a significant effect on the diffusivity of cesium in the geopolymers. It was shown that, in addition to the pore structure and surface area, the mobility of water affects the diffusion performance of the geopolymer.
  • OMATSU Hiroaki, YAMADA Yuya, KURUMISAWA Kiyofumi
    Cement Science and Concrete Technology 一般社団法人 セメント協会 74 (1) 44 - 50 0916-3182 2021/03/31 [Not refereed]
     
    Studies have been conducted on accelerators to improve the delay of initial strength development of blast furnace cement in cold regions. And their effects have been reported with various inorganic salts. However, it is still not clear that how influence inorganic salts on the reaction of blast furnace slag in blast furnace cement. In this study, we focused on inorganic salts, which are the main constituents of accelerators, and tried to elucidate their effects on reaction of blast furnace slag and their reaction mechanism. As a result, it was found that the addition of inorganic salts increased the reaction degree of blast furnace slag and enhanced the strength development. And it was also shown that the difference in aluminate hydrates produced by the reaction of blast furnace slag affected the strength development.
  • KURMISAWA Kiyofumi
    Cement Science and Concrete Technology 一般社団法人 セメント協会 74 (1) 105 - 110 0916-3182 2021 [Refereed]
     

    In cold region such as Hokkaido, when placing concrete in winter, it is necessary to carry out appropriate curing. However, blast furnace slag cement concrete requires longer curing than ordinary Portland cement concrete. Therefore, in order to increase the use of blast furnace cement for concrete production, it is necessary to improve strength development in early age. The purpose of this study is to clarify the influence of inorganic salts on the reaction of blast furnace slag powder. In this study, we focused on hardened blast furnace slag and calcium hydroxide to clarify the influence of inorganic slats. As a result, it was clarified that the initial strength enhancement of the sample mixed with sodium sulfate was high. It was confirmed by solid-state NMR that the aluminate hydrates and the Si chain polymerization differed depending on the inorganic salt to be mixed.

  • 大松宏彰, 山田優也, 胡桃澤清文
    セメント・コンクリート論文集(Web) 74 (1) 2187-3313 2021 [Refereed]
  • Kiyofumi Kurumisawa, Kazuko Haga, Masahito Shibata, Daisuke Hayashi
    Journal of Advanced Concrete Technology 19 (5) 426 - 432 1346-8014 2021 [Refereed]
     
    Cement-based materials used at radioactive waste disposal sites are required to possess long-term stability. However, when these materials come in contact with groundwater, calcium leaching from the solid occurs, and the material becomes porous. The use of mineral admixtures is recommended to minimize porosity. However, few studies have focused on the diffusion performance of cement-based materials blended with mineral admixtures after leaching. Therefore, in this study, the diffusion performance of such materials using blended cement after leaching was evaluated. It was found that the diffusion coefficient of the blended cement increased with leaching, and when leaching progressed considerably, the diffusion coefficient of the blended cement was close to that of ordinary Portland cement. Furthermore, the diffusion coefficient after leaching demonstrated good correlation with the pore volume when the pore diameter was 50 nm or larger.
  • Kiyofumi Kurumisawa, Ole Mejlhede Jensen
    Journal of Advanced Concrete Technology 18 (8) 456 - 462 1346-8014 2020/08/12 [Refereed][Not invited]
     
    In this study, thermoporometry by differential scanning calorimetry and proton NMR measurements of hardened cement paste equilibrated under different humidity conditions were carried out, and the results of both measurements were compared. The results reveal that thermoporometry by low temperature DSC measurement cannot detect the water present in samples equilibrated at low relative humidity. On the other hand, it is possible to detect a signal at low relative humidity by proton NMR measurement. It is clarified that water strongly bound to the surface, which cannot be detected by low temperature DSC, exists at a relative humidity of 33% or less. If it is relevant to detect tightly held water, such as water present in the fine gel pores, it is recommended to apply proton NMR measurements. This paper is an extended English version of the authors' previous work [Kummisawa, K. and Jensen, O. M., (2020). "Measurement of cement paste at different humidities by thermoporometry and proton NMR." Proceedings of the Japan Concrete Institute, 42, 347-352. (in Japanese)].
  • 山田優也, 胡桃澤清文
    セメント・コンクリート論文集(Web) 73 (1) 2187-3313 2020
  • 胡桃澤清文
    セメント・コンクリート論文集(Web) 73 (1) 2187-3313 2020
  • 胡桃澤清文, JENSEN Ole M.
    コンクリート工学年次論文集(CD-ROM) 42 2424-0281 2020 [Refereed]
  • KURMISAWA Kiyofumi
    Cement Science and Concrete Technology 一般社団法人 セメント協会 73 (1) 111 - 117 0916-3182 2020 [Refereed][Not invited]
     

    In cold region such as Hokkaido, when placing concrete in winter, it is necessary to carry out appropriate curing. However, blast furnace slag cement concrete requires longer curing than ordinary Portland cement concrete. Therefore, in order to increase the use of blast furnace cement for concrete production, it is necessary to improve initial strength development. The purpose of this study is to clarify the influence of hardening accelerator on the reaction of blast furnace slag powder. In this study, we focused on hardened blast furnace slag and calcium hydroxide to clarify the influence of accelerators. As a result, it was clarified that the initial strength enhancement of the sample mixed with nitrite-type accelerator was high. Moreover, it confirmed that the nitrite type-AFm was produced as a hydrate in sample with nitrite-type accelerator. Also, it was shown from the results of phase equilibrium model calculation that the volume of the hydrate did not change significantly.

  • YAMADA Yuya, KURUMISAWA Kiyofumi
    Cement Science and Concrete Technology 一般社団法人 セメント協会 73 (1) 103 - 110 0916-3182 2020 [Refereed][Not invited]
     

    The use of blast furnace cement is being promoted to reduce CO2 emissions during cement production, but in cold climates such as Hokkaido region there is a concern that initial strength of blast furnace cement may decrease by using air entrained agent （AE） for improving freeze-thaw resistance and scaling may occur. However, increase with air content decrease compressive strength, although it is possible to take measures by mixing a novel accelerator using a combination of a polyol and a sulfate and a new frost damage inhibitor for concrete such as oil type as a new method that is independent of air content, it has not been investigated whether the combined use of these agents suppresses the development of initial strength. Moreover, the effect of combined use of accelerator and a frost damage inhibitor on the reaction of blast furnace slag is not clear. Therefore, in this research, we clarified the mechanism of the strength development of the hardened blast furnace slag cement using the frost damage inhibitor and the accelerator together by performing a strength test and phase composition analysis by XRD Rietveld method and SEM observation. As a result, it was found that the C3S and C3A reaction rate increased by the accelerator, and the frost damage inhibitor did not inhibit the reaction.

  • Kenta Sasaki, Kiyofumi Kurumisawa, Kouhei Ibayashi
    CONSTRUCTION AND BUILDING MATERIALS 216 337 - 346 0950-0618 2019/08 [Refereed][Not invited]
     
    Geopolymer concrete presents a major problem regarding its practical application, in that the geopolymer paste has very short setting time. Previous studies have shown that the addition of blast furnace slag to geopolymer paste considerably shortens the setting time. Based on these findings, in the present study, setting retarders were used to lengthen the setting time of the geopolymer paste. The objective of the present study was to identify the effect of a setting retarder on the fluidity and compressive strength of alkali-activated fly ash/blast furnace slag-based materials. It was shown that, by adding a chelator as a retarder, the setting time can be prolonged. However, the setting time was found to be dependent on the type of chelator. Similarly, the compressive strength development of the geopolymer was also found to be dependent on the type of chelator. It was clarified that the concentration of calcium and aluminum in solution during hardening changes with the addition of a chelator, and it was shown that there is a correlation between the concentrations of calcium and aluminum and the setting time. (C) 2019 Elsevier Ltd. All rights reserved.
  • Ali Jamshidi, Greg White, Mehdi Hosseinpour, Kiyofumi Kurumisawa, Meor Othman Hamzah
    CONSTRUCTION AND BUILDING MATERIALS 217 487 - 497 0950-0618 2019/08 [Refereed][Not invited]
     
    The effects of the reclaimed asphalt pavement (RAP) source and content on the dynamic modulus (E*) of hot mix asphalt concrete were characterized. Two parameters were proposed: the non-dimensional dynamic modulus-temperature index (del E-T*) and non-dimensional dynamic modulus-frequency index (del E-fr*). Parameter del E-fr* indicates the increase of relative E* per unit percent RAP from different sources during frequency and temperature sweeps, while del E-T* characterizes the reduction of relative E* per 1 degrees C temperature increase. An analysis of the results showed that del E-T* of RAP mixes were 6.80% to 12% higher than those of the control samples, indicating less temperature susceptibility. Furthermore, an analysis of del E-fr* trends showed temperature independency at higher temperature ranges. In addition, the results showed that the activation energy (AE) of the mixes was 1.51 MJ/mol/K to 9.86 MJ/mol/K higher than that of the control samples (without RAP), which depends on the RAP content and source. Moreover, E* linearly increases as AE increases. In conclusion, the increase of intermolecular forces owing to the higher AE in the blended binders increased the mix stiffness, which resulted in a higher E* in mixes containing RAP. (C) 2019 Elsevier Ltd. All rights reserved.
  • Ali Jamshidi, Kiyofumi Kurumisawa, Gregory White, Tatsuo Nishizawa, Toshifumi Igarashi, Toyoharu Nawa, Jize Mao
    CONSTRUCTION AND BUILDING MATERIALS 200 713 - 755 0950-0618 2019/03 [Refereed][Not invited]
     
    Researchers dealing with pavements and experts on materials have been increasingly focused on the structural strength of the pavement materials without paying sufficient attention to the environment and cultural norms. In the 21st century, the concept of pavement design and rehabilitation needs to be modified owing to new requirements such as the additional structural loads derived from the climate change, environmental challenges, social requirements, and aging population. Therefore, the concept of post-modern pavement (PMP) was proposed to address the structural, sustainability, and sociopsychological requirements. In this review of the state-of-the-art, the potential of the interlocking concrete block pavement (ICBP) was evaluated based on its laboratory and field structural performance, sustainability, and social acceptance as a PMP in Japan. Therefore, the relevant literature in English and Japanese, including journals, conference proceedings, technical reports, books, and theses, over a span of 47 years (1971-2018), were studied. It was found that the structural and functional performances of the ICBP in different facilities were satisfying. Furthermore, owing to its waste material use, less noise emission, air purifying characteristics, and heat island reduction, the environmental performance of ICBP was in harmony with sustainable practices. In addition, pavements users, both able and differently abled, rated the ICBP as a more appropriate pavement system owing to its physical appearance, serviceability, aesthetic features, lower heat island effect, rapid maintenance, and positive psychologic effects after earthquake and tsunami events. As a result, the ICBP can be recommended as a PMP for the design and development of resilient transportation infrastructure assets in Japan. (C) 2018 Elsevier Ltd. All rights reserved.
  • Jamshidi, A., Kurumisawa, K., White, G., Jize, M., Nawa, T.
    Smart Nanoconcretes and Cement-Based Materials: Properties, Modelling and Applications 383 - 401 2019 [Refereed]
     
    Concrete pavements are commonly used infrastructural assets that require various types of materials. There are many technologies and materials to improve the engineering properties and sustainability of concrete pavements. One such technology that opens new horizons in civil engineering involves nanomaterials. Use of nanomaterials increases structural strength and durability against aggressive chemical compounds and elements that extend the effective service life of the concrete pavement. Furthermore, nanomaterials can enhance environmental stewardships of concrete pavements through the reduction of demand for raw materials for maintenance and rehabilitation. Therefore, nanomaterials play a pivotal role in the development of high-strength and low-energy concrete pavements, especially for heavy-duty applications. In this chapter, various types of nanomaterials and pertinent performance mechanisms on the structural response of concrete pavements are discussed. In addition, the results of laboratory and field studies on the environmental burdens of nano-concrete pavements are analyzed in detail. In conclusion, the challenges of nano-concrete pavements as resilient infrastructure are discussed.
  • 胡桃澤清文
    セメント・コンクリート論文集(Web) 72 (1) 2187-3313 2019
  • 小島真実, 佐々木健太, 胡桃澤清文
    セメント・コンクリート論文集(Web) 72 (1) 2187-3313 2019
  • OJIMA Mami, SASAKI Kenta, KURUMISAWA Kiyofumi
    Cement Science and Concrete Technology 一般社団法人 セメント協会 72 (1) 114 - 121 0916-3182 2019 [Refereed][Not invited]
     

    The use of blast furnace slag cement for concrete production with air entrained agent（AE）for improving freeze-thaw resistance in cold climates such as Hokkaido region cause the decrease of the initial strength of concrete. In order to improve initial strength of concrete, a novel curing accelerator using a combination of a polyol type and a sulfate type has been developed, and a high hydration acceleration effect is obtained by previous reports. However, its hydration acceleration mechanism has not been clarified in detail. In this study, attempts were made to elucidate the mechanism of initial strength development of blast furnace slag cement by adding a new curing accelerator. Firstly, we confirmed the strength development and ultrasonic pulse velocity of hardened cement pastes with/without the hydration accelerator. And we investigated the phase assemblage in hardened cement pastes by XRD Rietveld method, and the degree of reaction of blast furnace slag in hardened blast furnace slag cement pastes was determined by backscattered electron image. As a result, it is possible to accelerate the hydration reaction of the aluminate phase by combining the polyol type and the sulfate type of agent, there is a possibility that the curing accelerator dissolves the portlandite to accelerate the reaction of the blast furnace slag fine powder.

  • KURUMISAWA Kiyofumi
    Cement Science and Concrete Technology 一般社団法人 セメント協会 72 (1) 173 - 180 0916-3182 2019 [Refereed][Not invited]
     

    Mercury intrusion porosimetry has been widely used as a method to measure the pore structure of cementitious materials, but considering the influence on the environment, a method that does not use mercury is required. Also, in the mercury intrusion porosimetry, the sample is dried before measurement, so the measurement result indicates the pore structure of the dried sample. Therefore, a thermoporometry method can be proposed as a method not requiring the use of mercury and drying process of specimen. The thermoporometry method estimates the porosity from the amount of heat generated during the freezing and thawing of water in the pore. So far, the authors have measured with a small size of sample, but in this study the thermoporometry method was applied to the bulk sample. As a result, peaks which could not be measured with a small size of sample could be detected. And it was clarified that blending blast furnace slag forms finer pore structure of hardened cement paste. Therefore, transport properties of hardened cement paste with BFS was improved. It was also clarified that the diffusion of chloride ions in hardened cement paste depends on the pore volume of 6nm or more.

  • Ali Jamshidi, Gregory White, Kiyofumi Kurumisawa, Toyoharu Nawa, Toshifumi Igarashi, Meor Othman Hamzah
    JOURNAL OF CLEANER PRODUCTION 189 635 - 646 0959-6526 2018/07 [Refereed][Not invited]
     
    In this study, the effects of the warm-mix asphalt additive content, asphalt type, and various mixing and test temperatures on the creep stiffness and cumulative micro-strain of asphalt mixtures were analyzed. In addition, the correlation between the rheological properties of the warm mix binders and mixtures were evaluated. Furthermore, a new methodology, namely, the hypotenuse length and sustainable angle method, was proposed to analyze the structural environmental performance of the warm mix technology. The results showed that there was a close relationship between the properties of the asphalt binders and mixtures for various binder types and ageing states. Furthermore, the results indicated that this new methodology could be used by pavement and environment engineers to determine whether an asphalt mix is consistent with environmental regulations well as satisfying the structural performance requirements. (C) 2018 Elsevier Ltd. All rights reserved.
  • Elakneswaran Yogarajah, Toyoharu Nawa, Kiyofumi Kurumisawa
    JOURNAL OF MATERIALS IN CIVIL ENGINEERING 30 (5) 0899-1561 2018/05 [Refereed][Not invited]
     
    In this study, the surface electrical properties of calcium silicate hydrate (C-S-H) and their influence on ionic adsorption have been investigated to be able to predict chloride binding in slag-containing cementitious materials. The experimental data showed that the electrokinetic potential of slag cement paste (SCP) is intermediate between hydrated cement paste (HCP) and C-S-H with Ca/Si of 1.0 (C-S-H:1.0) or slag calcium hydroxide paste (SCHP). Two types of C-S-H available in the hydrated SCP for ionic adsorption are considered: one is similar to the C-S-H of HCP and other is like C-S-H:1.0. The surface complexation modeling parameters for ionic adsorption on C-S-H:1.0 were estimated by fitting the experimental data to simulation results. The estimated parameters for C-S-H:1.0 together with surface complexation modeling parameters for HCP were used to predict the adsorption of chloride on SCP. The simulation results show good agreement with experimental data and follow a Freundlich isotherm. When portland cement is partially replaced by slag, it modifies the surface electrical properties of C-S-H in addition to mineralogy and pore structure and leads to change in the chloride adsorption behavior.
  • Dejeto Rodrigo V, Kurumisawa Kiyofumi
    INTERNATIONAL JOURNAL OF ADVANCED AND APPLIED SCIENCES 5 (5) 110 - 115 2313-626X 2018/05 [Refereed][Not invited]
  • Ben Li, Lalita Baingam, Kiyofumi Kurumisawa, Toyoharu Nawa, Liu XiaoZhou
    CONSTRUCTION AND BUILDING MATERIALS 164 554 - 569 0950-0618 2018/03 [Refereed][Not invited]
     
    The alkali-silica reaction causes long-term degradation of microstructure of cement paste and aggregate, and as results in macroscopic expansion. In this paper, a micro-mechanical expansion model was developed coupling with the damage and thermodynamic theory. First of mortar thermal coefficients were estimating to determine the true expansion due to ASR based on EPMA and MIP results and expansion proposed in this paper were compared with analysis results of Suwito's and Multon's model. The results indicate that the increasing of temperature conducted reduced fluctuations of ASR expansion coefficient of cement paste. In addition, our proposed model accurately reproduces the true-dependency of expansion due to ASR with the lowest error. Overall, the proposed microscopic expansion model is able to apply for numerical analyse of deteriorated due to ASR concrete structure designs with in the deterioration of ASR in the future. (C) 2018 Elsevier Ltd. All rights reserved.
  • Ali Jamshidi, Kiyofumi Kurumisawa, Toyoharu Nawa, Bijan Samali, Toshifumi Igarashi
    JOURNAL OF CLEANER PRODUCTION 166 1507 - 1520 0959-6526 2017/11 [Refereed][Not invited]
     
    (BFS) and fly ash (FA), on the structural performance, energy requirement and environment impacts of a concrete heavy-duty pavement (HDP) at various curing temperatures. The results of the structural performance indicate that HDP containing up to 70% BFS and HDP containing 30% FA can be comparable in controlling the HDPs designed for highways and airports. Moreover, the results of the environmental impact assessment indicate that the synergy of the by-product and warm water can reduce the energy requirement and CO2 footprint by 5.77%-56.54% and 8.16%-55.5% for the highway and airport HDPs, respectively. Although the elevated curing temperature improves the structural performance and sustainability of the concrete pavements, any delay in concrete production increases energy consumption accordingly. Moreover, a new parameter (del(TE)), which is the time gradient per unit energy consumption developed based on the Laplace transformation, is proposed to characterize the effect of the time delay in concrete production. This parameter indicates that the time required for a unit energy consumption (1 TJ) decreases by 50%, as the curing temperature increases. In conclusion, analysis of the structural design, carbon footprint, and the results of del(TE) indicate that 35 degrees C can be proposed as the optimum water curing temperature for the HDP incorporating by-products. (C) 2017 Elsevier Ltd. All rights
  • Ali Jamshidi, Kiyofumi Kurumisawa, Toyoharu Nawa, Mao Jize, Gregory White
    JOURNAL OF CLEANER PRODUCTION 164 367 - 388 0959-6526 2017/10 [Refereed][Not invited]
     
    Pavements are one of the most energy-intensive infrastructure assets that depend on non-renewable natural resources. Against the background of restrictions on landfill disposal, the increased use of alternative materials such as industrial byproducts in pavement construction has gained great attention from academic and industrial sectors. However, comprehensive research covering various aspects of pavements incorporating different byproducts is lacking. The main purpose of this state-of-the-art study is to bridge this gap via the analysis of the performance of pavements incorporating two types of byproducts, blast furnace slag, and fly ash, from the perspectives of structural performance, energy saving potential, and greenhouse gas emission reduction at various phases of pavement life. Therefore, the contents of 150 published documents, including research papers, theses, and academic and industrial reports published over a span of 49 years (1968-201.7) were analyzed. The major findings indicated that incorporation of the byproducts may have positive or negative consequences in various phases of pavement life. However, the new pavements are advantageous from the viewpoint of raw material processing because of low consumption of raw materials and pertinent environmental footprints. In addition, several scenarios are proposed for ranking the alternative materials on the basis of the technical and environmental requirements for a paving project; these scenarios can be useful for the preliminary selection of alternative materials. Finally, some gaps are highlighted for future research. (C) 2017 Elsevier Ltd. All rights reserved.
  • Kiyofumi Kurumisawa, Kazuko Haga, Daisuke Hayashi, Hitoshi Owada
    PHYSICS AND CHEMISTRY OF THE EARTH 99 175 - 183 1474-7065 2017/06 [Refereed][Not invited]
     
    It is very important to predict alterations in the concrete used for fabricating disposal containers for radioactive waste. Therefore, it is necessary to understand the alteration of cementitious materials caused by calcium leaching when they are in contact with ground water in the long term. To evaluate the long-term transport characteristics of cementitious materials, the microstructural behavior of these materials should be considered. However, many predictive models of transport characteristics focus on the pore structure, while only few such models consider both, the spatial distribution of calcium silicate hydrate (C-S-H), portlandite, and the pore spaces. This study focused on the spatial distribution of these cement phases. The auto-correlation function of each phase of cementitious materials was calculated from two-dimensional backscattered electron imaging, and the three-dimensional spatial image of the cementitious material was produced using these auto-correlation functions. An attempt was made to estimate the diffusion coefficient of chloride from the three-dimensional spatial image. The estimated diffusion coefficient of the altered sample from the three-dimensional spatial image was found to be comparable to the measured value. This demonstrated that it is possible to predict the diffusion coefficient of the altered cement paste by using the proposed model. (C) 2017 Elsevier Ltd. All rights reserved.
  • Ali Jamshidi, Kiyofumi Kurumisawa, Toyoharu Nawa, Jize Mao, Ben Li
    JOURNAL OF TRAFFIC AND TRANSPORTATION ENGINEERING-ENGLISH EDITION 4 (2) 118 - 130 2095-7564 2017/04 [Refereed][Not invited]
     
    In this study, the effects of the thermal properties of asphalt binders and aggregate materials were characterized in terms of the specific heat capacity (C) for energy consumption and environmental footprints of hot mix asphalt (HMA) and warm mix asphalt (WMA). Asphalt mixes produced using low-C aggregate are found to be more energy-efficient and environmental friendly, irrespective of the binder type and construction technology. Therefore, different fractions of aggregate blends were replaced with the aggregate provided from a low-C source or sustainable source. Analysis of energy consumption clearly indicated that the specific energy and environmental footprints decrease linearly as the low-C aggregate content increases. The amount of energy saving realized in the asphalt industries by the use of low-C aggregate is significant on a national scale in China. In this regard, China was chosen as a case study. Analysis of fuel requirement clearly indicated that the production of WMA using high thermal sensitivity aggregate can yield significant energy saving sufficient to fuel 44,007 to 664,880 Chinese households per year. Therefore, use of low C aggregate in asphalt mix production can be adopted as a strategy to produce WMA and HMA. (C) 2017 Periodical Offices of Chang'an University. Publishing services by Elsevier B.V.
  • Hatanaka Akira, Elakneswaran Yogarajah, Kurumisawa Kiyofumi, Nawa Toyoharu
    Journal of Advanced Concrete Technology 公益社団法人 日本コンクリート工学会 15 (8) 426 - 439 1346-8014 2017 [Refereed][Not invited]
     

    The purpose of this study is to determine the tortuosity of cementitious materials containing blast furnace slag (BFS). Furthermore, the influence of tortuosity on multi-species transport into these materials is studied. The porosity and diffusivity of calcium silicate hydrate (C-S-H) were predicted using a three-dimensional spatial distribution model, which were then fitted to Archie's law to determine tortuosity. The tortuosity increased with the slag replacement ratio, suggesting that the diffusion path for ions becomes complicated and lengthy due to slag addition. Thermoporometry was used to determine the pore size distribution of hydrated slag-blended cement. A partial replacement of ordinary Portland cement (OPC) with BFS modified the mineralogy (especially in the types of C-S-H), resulting in changes to the pore structure. The determined tortuosity and porosity were used in a reactive transport model to predict multi-species transport. Experimentally measured and simulated chloride profiles were in good agreement for hydrated OPC and slag-blended cements exposed to sodium chloride solutions. The causes for the low penetration rate of chloride in slag-blended cementitious materials are discussed considering their pore structure and surface electrical properties. The role of tortuosity on Cl-/OH- for the evaluation of chloride induced corrosion was also discussed.

  • SUGIYAMA Takuya, MIYAMOTO Masanori, KURUMISAWA Kiyofumi, HATANAKA Akira
    Cement Science and Concrete Technology 一般社団法人 セメント協会 71 (1) 177 - 184 0916-3182 2017 [Refereed][Not invited]
     

    The importance of maintenance and repair of existing concrete buildings has increased. Therefore, it is necessary to know the exact deterioration condition of a concrete building structure, so it is required to accurately measure the pore structure. As one of the measurement techniques, thermoporometry has been proposed. Thermoporometry does not need drying and applying high pressure to specimen during measurement, so there is little risk of damage to the cement paste. In this study, we measured some physical property（uniaxial compressive strength, ultrasonic velocity, electric conductivity, and chloride ion diffusion）and pore structure of OPC paste and fly ash cement paste. And we investigated the relationship between the physical properties and the pore structure measured by using thermoporometry and mercury intrusion porosimetry. As a result, the uniaxial compressive strength and the ultrasonic velocity can be estimated by using pore volume measured by thermoporometry and mercury intrusion porosimetry. Transport properties such as the electric conductivity and chloride ion diffusion could be estimated by separating each OPC paste and fly ash cement paste. And it was suggested that the diffusivity could be estimated by using the quantity of pore volume detected in the freezing process around －15℃ which is the connected capillary pore volume.

  • Ali Jamshidi, Kiyofumi Kurumisawa, Toyoharu Nawa, Toshifumi Igarashi
    RENEWABLE & SUSTAINABLE ENERGY REVIEWS 64 211 - 236 1364-0321 2016/10 [Refereed][Not invited]
     
    This paper discusses the engineering properties of waste glass (WG), including its structural and environmental performance, as an alternative material for the construction of various types of paving systems, including asphalt, concrete, and block pavements. As a first step, an overview of the asphalt, cement, and glass manufacturing industries is provided. Then, a large volume of data is analyzed from various sources in the literature. Particular emphasis is given to laboratory studies of the structural performance and durability of WG. Additionally, the effect of WG on the field performance of the pavements is discussed. The sustainability of the pavements is also evaluated in terms of energy consumption, greenhouse gas emissions, safety, and the heat island phenomenon. In conclusion, the use of WG can improve various phases of pavement life and structure by enhancing the structural performance, durability, environmental friendliness, and aesthetic features of pavements. (C) 2016 Elsevier Ltd. All rights reserved.
  • Ali Jamshidi, Meor Othman Hamzah, Kiyofumi Kurumisawa, Toyoharu Nawa, Bijan Samali
    MATERIALS & DESIGN 95 9 - 20 0264-1275 2016/04 [Refereed][Not invited]
     
    There are many technologies to produce sustainable asphalt pavements that may affect various phases of pavement life. Therefore, it is difficult to choose the most appropriate technology that addresses all the engineering requirements, especially in the technologies produce the identical outputs. In this study, a PG64 asphalt binder (base binder) was upgraded to PG70 (target binder) through incorporation of two different sustainable approaches: (1) synthetic wax and (2) recovered binder from reclaimed asphalt pavement (RAP). The effects of the different modification methods were evaluated in terms of the engineering properties of materials and the sustainability features of mix production. The results indicated the modified binder (as outputs) have the same performance grade as the target binder, but the incorporation of RAP reduces the environmental pollutants at the stage of raw material processing, while the use of the wax decreases the pollutants during asphalt mix production. Consequently, the selection of the type of sustainable technology for production of cleaner asphalt pavement depends significantly on the stage desired to be modified in the pavement construction. A few scenarios and a new method are also proposed as a guide to selection of the appropriate sustainable approaches based on the binder and engineering properties. (C) 2016 Elsevier Ltd. All rights reserved.
  • MIYAMOTO Masanori, SUGIYAMA Takuya, KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 70 (1) 134 - 140 0916-3182 2016 [Refereed][Not invited]
     

    The purpose of this research is to understand the mass transfer characteristics of concrete to predict the durability of the concrete. There is a close relationship between transport properties of several ions and adsorption ability. It was reported that the adsorption ability of the concrete is changed with the calcium leaching of concrete caused by contact with such as groundwater in a long-term. It was also reported that the adsorption ability of the Calcium-silicate-hydrate（C-S-H）is dependent on its CaO/SiO2（Ca/Si）ratio, but the sample in their research is only White Portland Cement（WPC）and Blast Furnace Slag（BFS）cement. On the other hand, it is reported that FA cement has a high resistance to calcium leaching. In this study, leaching experiments using ammonium nitrate solution and chloride ion adsorption experiment were carried out for FA specimens. It was shown that Ca/Si ratio of C-S-H in each sample is decreased with and Al2O3/SiO2（Al/Si）ratio of C-S-H is increased with calcium leaching. The amount of chloride ion adsorption is linearly decreased with its Ca/Si ratio and Al/Si ratio. Finally, we established the equation for predicting the amount of chloride adsorption in C-S-H with different Ca/Si ratio and Al/Si ratio.

  • KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 70 (1) 230 - 235 0916-3182 2016 [Refereed][Not invited]
     

    It is necessary to evaluate transport properties of concrete for lengthening the durability of concrete, therefore it is very important to measure the pore structure of hardened cement paste precisely in understanding mass transport properties. The electric conductivity by the AC impedance method have been suggested as simple and accurate technique to understand it, and the usefulness is reported in the case of hardened cement paste used with ordinary Portland cement. However, this technique has not been applied for hardened cement paste mixed with fly ash that has very high resistance to chloride ingress. In this study, chloride ingress and microstructure of the fly ash cement paste was investigated by the electric conductivity measurement. The AC impedance method was applied to measure the electric conductivity of specimen, and backscattered electron image analysis and mercury intrusion method was applied for measuring pore structure in fly ash cement paste. As a result, the conductivity of fly ash cement paste was strongly depended on degree of reaction of fly ash. It was shown that a very high correlation was shown in chloride diffusion coefficient and electric conductivity regardless of a fly ash replacement ratio.

  • Kurumisawa Kiyofumi, Nawa Toyoharu
    Journal of Advanced Concrete Technology 公益社団法人 日本コンクリート工学会 14 (3) 87 - 94 1346-8014 2016 [Refereed][Not invited]
     
    The transport properties of hardened cement paste (HCP) have been investigated in many studies; the AC impedance method (ACI) is a non-destructive technique employed for this purpose and has been used in investigations of the elec-trical characteristic and mass transport properties of HCP. However, there are relatively fewer studies investigating chloride ingress in HCP and using the ACI. In this study, the relationship between the electrical conductivity measured by the ACI and chloride ingress was investigated. Backscattered electron image analysis and mercury intrusion porosimetry and water porosity were used to measure the pore structure of HCP, and the chloride ingress depth was measured by an electron probe microanalyzer. There was a high correlation between the porosity and conductivity and between the conductivity and diffusion coefficient of the chloride ions in HCP. This implies that the diffusion coefficient of chloride ions could be estimated by the conductivity measurements.
  • Ali Jamshidi, Kiyofumi Kurumisawa, Toyoharu Nawa
    INFRASTRUCTURE ASSET MANAGEMENT 2 (4) 186 - 186 2053-0242 2015/12 [Refereed][Not invited]
  • Kiyofumi Kurumisawa
    CONSTRUCTION AND BUILDING MATERIALS 101 (P1) 926 - 931 0950-0618 2015/12 [Refereed][Not invited]
     
    Mercury intrusion porosimetry (MIP) has been widely used for the evaluation of the pore structure of hardened cement paste. However, treatment with mercury is dangerous and causes environmental damage. Therefore, we investigated the pore structure of hardened cement paste by thermoporometry (TPM) using low-temperature differential scanning calorimetry (LT-DSC) measurements as an alternative to MIP in this study. The compressive strength, ultrasonic pulse velocity, and electrical conductivity Were measured as the properties of hardened cement paste. Good correlation was demonstrated between the pore volume measured by TPM and these properties. It was shown that it is possible to evaluate the properties of hardened cement paste by TPM using LT-DSC. (C) 2015 Elsevier Ltd. All rights reserved.
  • Ali Jamshidi, Kiyofumi Kurumisawa, Toyoharu Nawa, Meor Othman Hamzah
    JOURNAL OF CLEANER PRODUCTION 90 195 - 210 0959-6526 2015/03 [Refereed][Not invited]
     
    In this study, the effects of various blast furnace slag (BFS) contents on the performance of cement pastes and pavement were investigated at two levels, the micro and the macro. At the micro level, the strength and chemical properties of cement pastes containing various percentages of BFS and subjected to different water curing periods were evaluated. At the macro level, the structural and sustainability performance of airport concrete pavements were studied. In this regard, several structural design charts were developed to determine the thickness of the concrete slab required to withstand traffic loadings for various versions of aircraft design and subgrade strengths. The sustainability of the concrete pavements was assessed in terms of fuel requirements and greenhouse gas (GHG) emissions. In addition, a simple graphical method was proposed for comparing structural and environmental performance of concrete pavements with respect to BFS content, subgrade strength, different versions of the aircraft design, fuel requirements and GHG emissions for pavement construction. Based on the results obtained using the proposed method and the structural and sustainability analyses, scenarios are suggested for choosing preliminary BFS content. (C) 2014 Elsevier Ltd. All rights reserved.
  • KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 69 (1) 207 - 213 0916-3182 2015 [Refereed][Not invited]
     
    Hardened cement paste with various inorganic electrolytes was prepared for investigating the effect of pore structure and pore solution on electric conductivity and transport properties. As a result, it was shown that the correlation between the total pore volume measured by mercury intrusion method and the apparent diffusivity of the chloride ion of hardened cement paste was low. On the other hand, it was shown that relationship between the diffusivity of the chloride ion and electric conductivity of the hardened cement paste by the AC impedance method was linear as reported Nernst-Einstein equation. From this result, it was shown that it is possible to estimate the diffusivity of hardened cement paste by the electric conductivity measurement even if pore structure and pore solution of hardened cement paste changed.
  • MIYAMOTO Masanori, KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 69 (1) 183 - 190 0916-3182 2015 [Refereed][Not invited]
     
    It is important to evaluate the physical properties of the cement-based materials from pore structure for predicting the durability of cement based materials. Mercury Intrusion Porosimetry（MIP）is widely used for pore structure measurement method. However, it was reported that micro structure of hardened cement paste was destroyed by the drying treatment and applied high pressure. To solve them, low-temperature differential scanning calorimetry（LT-DSC）based on thermoporometry was proposed. However, studies about LT-DSC are few. Therefore, the effectiveness of LT-DSC measurement in pore structure measurement is not clear. In this study, we investigated whether pore structure measured by LT-DSC can evaluate physical properties of hardened cement paste. By comparing the results of LT-DSC and MIP, it was suggested that the measurement by MIP might cause the destruction in micro structure by drying and applied high pressure. It was cleared that it is possible to evaluate physical properties by total pore volume measured by LT-DSC. Moreover, it was indicated that threshold pore radius of the chloride ion diffusion was 7nm by using pore size distribution measured by LT-DSC.
  • Kiyofumi Kurumisawa, Haruka Abe, Toyoharu Nawa
    CONCREEP 10: MECHANICS AND PHYSICS OF CREEP, SHRINKAGE, AND DURABILITY OF CONCRETE AND CONCRETE STRUCTURES 1046 - 1052 2015 [Refereed][Not invited]
     
    The durability of the concrete structure is determined by transport properties of concrete. The transport of chloride ions greatly changes by the amount of adsorption by hydrates. However, there are few studies on change of the amount of adsorption with the calcium leaching. In this study, the purpose is to investigate a change of the amount of adsorption of the chloride ion with the calcium leaching of hardened cement pastes. The amount of chloride ion adsorption increased with the increase of the replacement ratio of the blast furnace slag. We established an equation to predict the amount of chloride ion adsorption on C-S-H and Afm. It was clarified that the amount of chloride ion adsorption on C-S-H of leached hardened cement paste depends on Ca/Si and Al/Si.
  • KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 68 (1) 171 - 177 0916-3182 2014 [Refereed][Not invited]
     
    It is very important to evaluate the concrete durability for realizing sustainable society. The concrete durability is dependent on its transport properties. Therefore, it is necessary to measure the transport properties of concrete accurately. Nondestructive method is useful to measure transport properties of concrete. The resistivity measurement which is one of the nondestructive methods was proposed to measure the transport properties. It was reported that the resistivity and diffusion property is related. However, the resistivity（conductivity）is influenced by some factors such as aggregate content and water content of concrete. In this study, we investigated the conductivity of mortar for clarifying the effect of sand content or water to cement ratio（W/C）on the conductivity of mortar. As a result, mortar conductivity was dependent on its paste conductivity and the amount of sand. And it was possible to predict the conductivity of mortar by the proposed equation with water to cement ratio. It was shown that the effect of interfacial transition zone between sand and paste on conductivity is limited from the calculation of NIST model. It was clarified that there is good correlation between ultrasonic pulse velocity and electric conductivity of mortar. Finally, we suggested an equation to estimate the ultra-sonic pulse velocity of mortar from the conductivity.
  • ABE Haruka, ISHIGAKI Kunihiko, KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 68 (1) 226 - 232 0916-3182 2014 [Refereed][Not invited]
     
    It is very important to understand mastransport properties of aggressive substances the concrete to exactly predict the durability of the concrete. Transport properties of several ions concrete is influenced by its adsorption. It was clarified in previous reports that the adsorption ability is changed with the calcium leaching of concrete during service life. It was also reported that the adsorption ability of the C-S-H is depended on its Ca/Si. However, it is the report only for hardened white cement paste（WPC）. In this study, blast furnace slag（BFS）was used for clarifying the effect of BFS on the adsorption ability of cement-based materials is investigated. As a result, the chloride adsorption ability of the specimen mixed with BFS had higher than that of only WPC even if calcium leaching occurs. It was shown that Ca/Si and Al/Si of C-S-H in specimen mixed with BFS changed with calcium leaching. And it was cleared that both of Ca/Si and Al/Si of C-S-H in specimen mixed with BFS had influence on the chloride adsorption ability. The chloride adsorption ability of C-S-H was shown to be correlated with the quantity of Q2Al in C-S-H from results of the 29Si-NMR. Finally, we established an prediction equation the chloride adsorption ability using Ca/Si and Al/Si of C-S-H.
  • K. Kurumisawa, H. Owada, M. Shibata
    Mechanics and Physics of Creep, Shrinkage, and Durability of Conrete: A Tribute to Zdenek P. Bazant - Proceedings of the 9th Int. Conf. on Creep, Shrinkage, and Durability Mechanics, CONCREEP 2013 285 - 292 2013/11/15 [Not refereed][Not invited]
     
    The porosity of hardened cement paste changes when it is exposed to the actual environments, and it may be expected that the chemical structure of the C-S-H undergoes changes. The C-S-H is the main component, comprising 60% or more by volume of hardened cement paste, and this study focuses on changes in the chemical structure of C-S-H. Deterioration induced by ammonium nitrate solution was accompanied by changes in the pore structure as well as structural changes in the C-S-H in the hardened cement paste. It was ascertained that when evaluating the decreases in the elastic modulus of the hardened cement paste, both the pore structure and the structure of the C-S-H must be considered. © 2013 American Society of Civil Engineers.
  • Kiyofumi Kurumisawa, Toyoharu Nawa, Hitoshi Owada, Masahito Shibata
    CEMENT AND CONCRETE RESEARCH 52 190 - 195 0008-8846 2013/10 [Refereed][Not invited]
     
    In this report, X-ray photoelectron spectroscopy (XPS) and Si-29-MAS-NMR was used for the evaluation of deteriorated hardened cement pastes. The deterioration by ammonium nitrate solution was accompanied by changes in the pore structure as well as by structural changes in the C-S-H in the hardened cement paste. The CaO/SiO2 ratio of the C-S-H decreased with the progress of deterioration, there was also polymerization of the silicate in the C-S-H. It was confirmed that the degree of polymerization of silicate of the C-S-H in hardened cement paste can be determined by XPS. It was also shown that the polymerization depends on the structure of the C-S-H. (C) 2013 Elsevier Ltd. All rights reserved.
  • KURUMISAWA Kiyofumi, MURAKAMI Yuto, ISHIGAKI Kunihiko, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 67 (1) 137 - 143 0916-3182 2013 [Refereed][Not invited]
     
    Cement based materials such as the concrete are used as barriers of the radioactive waste disposal facilities. As for the cement based materials, the capacity for binding of the radionuclide is required in facilities, and the ability to control the leak of the nuclide to the external environment is also expected by the low diffusivity of cement based materials. The transport of radionuclide has to be controlled leakage to the external environment in the radioactive waste disposal facilities during 10,000 years. Therefore, the appropriate design of the radioactive disposal facilities is necessary, and the accurate mass transfer prediction model that considered the calcium leaching of cement based materials with the order for tens of thousands of years to evaluate it safely is necessary. In our current model, there is a difference between measurement and predicted value of chloride ion ingress as simulated a nuclide movement in the calcium leaching region of hardened cement paste. It is considered that the input parameter for the capacity for binding of the chloride ion of the hardened cement paste in calcium leaching region is not appropriate. The purpose of this study is to clarify the capacity for the binding of the hardened cement paste that calcium leaching occurred quantitatively.
    In the experiment, ammonium nitrate solution was used to accelerate calcium leaching of the hardened cement paste. The hardened cement paste with different composition by changing the immersion period was produced. The capacity for binding of the chloride ion by immersing the sample in NaCl solution was determined. In addition, the mineral composition of hardened cement paste was determined by the powder X-ray diffraction with Rietveld method, and the chemical bonding state of the silica chain of calcium silicate hydrate（C-S-H） was measured by a solid nuclear magnetic resonance device（NMR） to clarify the mechanism that quantity of chloride ion adsorption changed. The results in this study are followings. As immersion period became long, the CaO/SiO2 ratio of C-S-H in sample which immersed in ammonium nitrate solution decreased, and the capacity for chloride ion binding of leached sample also decreased. As for this reason, the decrease of the adsorption site by the polymerization of silica chains in C-S-H was suggested by the results obtained from NMR measurement, and monosulfate which was one of the hydrates in hardened cement paste was disappeared by calcium leaching. The capacity for chloride ion binding of hardened cement paste was formulated by the results of experiments, and it was able to estimate the predicted value with less than 25％ of errors.
  • 胡桃澤清文, 名和豊春
    コンクリート工学年次論文集(CD−ROM) 34 ROMBUNNO.1081  1347-4111 2012/06 [Refereed][Not invited]
  • Kiyofumi Kurumisawa, Toyoharu Nawa, Hitoshi Owada
    Cement and Concrete Composites Elsevier 34 (3) 408 - 418 0958-9465 2012/03 [Refereed][Not invited]
     
    A three-dimensional image of hardened cement paste was reconstructed using a backscattered electron image (BE!) and used to predict the diffusion properties of hardened cement paste. After the BEI observations, an autocorrelation function (ACF) was calculated for each phase of the hardened cement paste, including the unhydrated cement, portlandite, and large pores. A three-dimensional image was reconstructed on the basis of the ACF based on random distributions. The dynamic elastic modulus and diffusion coefficient were calculated using a finite-element or finite difference method with the reconstructed three-dimensional images. The elastic modulus of the C-S-H phase was determined by micro-indentation, and the diffusivity of C-S-H was calculated using this elastic modulus based on previous reports. The resulting predicted dynamic elastic moduli and diffusion coefficients were in good agreement with the experimental results. Although, it was observed that the predicted values of the diffusivity of the blended cement pastes is different from the measured values, a new relationship between diffusivity and porosity of C-S-H in blended cement pastes was developed in this study. (C) 2011 Elsevier Ltd. All rights reserved.
  • NAWA Toyoharu
    セメントコンクリート セメント協会 (779) 38 - 43 0371-0718 2012/01/10 [Refereed][Not invited]
  • ISHIGAKI Kunihiko, KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 66 (1) 111 - 118 0916-3182 2012 [Refereed][Not invited]
     
    Bleeding is defined as the upward movement of water after a concrete has been placed, but it has set. It affects on the physical properties of the cured concrete. However the effect of bleeding on the microstructure has not yet been understood quantitatively. In this study, the pore structure of hardened cement paste（HCP）which was deformed by bleeding was discussed quantitatively using electron microscopy method and thermoporometry by low temperature differential scanning calorimeter（DSC）. Connectivity of pore structure was also examined by the LCR meter. It is clear that bleeding increases capillary pore in the upper part of cement paste than the lower part, and has few influence on the pore which is smaller than capillary pore. In addition, a correlation was seen between the porosity and electrical conductivity of HCP regardless of bleeding. That suggests that the connectivity of the pore structure of hardened cement paste is strongly dependent on its porosity.
  • AOYAMA Takuto, KURUMISAWA Kiyofumi, NAWA Toyoharu, MURAKAMI Yuto
    Cement Science and Concrete Technology 一般社団法人 セメント協会 66 (1) 311 - 318 0916-3182 2012 [Refereed][Not invited]
     
    It is very important to predict the deterioration of concrete that is used for a storage container of the radioactive waste. Thus it is necessary to comprehend the deterioration of cement based materials associated with calcium leaching by contact with the ground water for the super long term. We built the prediction model of diffusion in the hardened cement paste in consideration of the change in microstructure of the hardened cement paste with the Ca leaching, which is used a Nernst-Plank equation, an electro-neutral condition, and a diffusion of ions based on the Debye-Huckel equation. As a result, we can predict the transport of ions of the hardened cement paste with calcium leaching over time and the distribution of ions.
  • KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 66 (1) 127 - 134 0916-3182 2012 [Refereed][Not invited]
     
    It is necessary to improve transport properties of concrete for lengthening the durability of concrete, therefore it is very important to measure the pore structure of hardened cement paste precisely in understanding mass transport properties. Measurement in electric conductivity by the AC impedance method is suggested as simple and easy technique to understand it, and the usefulness is reported in the case of hardened cement paste used with ordinary Portland cement. However, this technique has not been applied for hardened cement paste mixed with blast furnace slag that has very high resistance to chloride ingress. In this study, chloride ingress and microstructure of the blast furnace slag cement paste（BFSC）was investigated by the electric conductivity measurement. For measuring the electric conductivity the AC impedance method was applied, and backscattered electron image analysis and mercury intrusion method was used for measuring pore structure in BFSC. The relationship between porosity and the electric conductivity was expressed by the Archie's law that is expressed with exponential function, and very high correlation was shown in chloride penetration depth and electric conductivity regardless of a blast furnace slag replacement ratio.
  • AOYAMA Takuto, KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 65 (1) 161 - 167 0916-3182 2011 [Refereed][Not invited]
     
    It is very important to predict the deterioration of concrete that is used for a storage container of the radioactive waste. So it is necessary to comprehend the deterioration of cement based materials associated with calcium leaching by contact with the ground water for the super long term. However, there are not many knowledge about the diffusion performance of deterioration of calcium silicate hydrate associated with calcium leaching. Therefore, this study focused on the degradation of calcium silicate hydrate with calcium leaching, in order to gain the knowledge of the transport properties of calcium silicate hydrate. As a result, there was the correlative relationship between porosity in calcium silicate hydrate and the diffusion coefficient of chloride ion of calcium silicate hydrate associated with calcium leaching. Also, we attempted to estimate the diffusion coefficient of chloride ion in the calcium leached hardened cement paste from plain hardened cement pastes, with the deterioration of calcium silicate hydrate and calcium hydroxide. And there was no difference between estimated value of the diffusion coefficient and measured one. Therefore, it was shown that it was important to consider the leaching of calcium hydroxide and the degradation of calcium silicate hydrate in order to predict of the transport properties of cement based materials.
  • RECONSTRUCTION OF THREE-DIMENSIONAL SPATIAL IMAGE OF HARDENED CEMENT PASTE
    Proceeding of the 13th ICCC Congress CDROM  2011 [Refereed][Not invited]
  • Interfacial Chemistry of C-S-H on Waste Ion Immobilization
    Proceeding of the 13th ICCC Congress CD-ROM  2011 [Not refereed][Not invited]
  • IDE Takayuki, AOYAMA Takuto, KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 65 (1) 464 - 469 0916-3182 2011 [Refereed][Not invited]
     
    Recently, ultra high strength concrete（UHSC）over compressive strength of 150N/mm2 was developed. Ultra high strength concrete property is determined by its composition such as cement type, fine aggregate, coarse aggregate. Especially coarse aggregate was critical for making UHSC, because stress concentration is occurred at contact zone of aggregate and cement matrix. In this study, we applied to nonlinear voxel finite element method with three dimensional image of concrete. As a result, static elastic modulus and compressive strength was able to predict by this method within 10％ in error. Moreover, it was shown that the fracture strength of coarse aggregate, and the difference between the elastic modulus of mortar matrix and coarse aggregate is very important to achieve the ultra high strength of concrete.
  • Y. Elakneswaran, A. Iwasa, T. Nawa, T. Sato, K. Kurumisawa
    CEMENT AND CONCRETE RESEARCH 40 (12) 1756 - 1765 0008-8846 2010/12 [Refereed][Not invited]
     
    The main objective of this investigation is to describe the interaction between cement hydrates and electrolyte solution to understand multi-ionic transport in cementitious materials. A surface complexation model in PHREEQC including an electrostatic term is used to simulate the ionic adsorption on the calcium silicate hydrate (C-S-H) surface. The equilibrium constants for the adsorption of ions on C-S-H surfaces are obtained by fitting experimental data to the model. The adsorption of both divalent and mono-valent cations, and also anions significantly changes the surface charges of hydrated paste. Chloride is being held in a chemical binding as Friedel's salt and bound mainly by the adsorptive action of C-S-H. An integrated modelling approach employing a phase-equilibrium model, a surface complexation model, and a multicomponent diffusion model has been developed in PHREEQC to simulate the multi-ionic transport through hydrated cement paste. It was found that the physical adsorption of ions on C-S-H, the size of pores, and the surface site density of C-S-H govern the rate of penetration of ionic species. Finally, the proposed model has been validated against chloride profiles measured in this study as well as with data available in the literature for hydrated cement paste. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.
  • 硬化セメントペーストの圧縮強度評価に対する非線形ボクセル有限要素解法とその適用可能性
    永井 学志, 池田 翔太, 胡桃澤 清文
    1 - 11 2010/08/09 [Not refereed][Not invited]
  • 永井 学志, 池田 翔太, 胡桃澤 清文
    計算工学講演会論文集 = Proceedings of the Conference on Computational Engineering and Science 日本計算工学会 15 (2) 861 - 864 1342-145X 2010/05 [Refereed][Not invited]
  • 永井学志, 池田翔太, 胡桃澤清文
    日本計算工学会論文集(Web) 日本計算工学会 2010 (2010) 20100012 - 20100012 1347-8826 2010 [Refereed][Not invited]
     
    To predict the macroscopic compressive strengths of hardened cement paste, a digital-image-based finite element procedure for damage evolution due to local tension is developed and its applicability from practical viewpoint is studied through numerical experiments. In the procedure, microscopic three-dimensional geometries of hardened cement paste are assumed to be periodic and each phase is randomly generated by using auto-correlation function evaluated from a two-dimensional SEM image of specimen. Nonlocal isotropic damage model is employed to represented crack evolutions in the geometries. Predicted macroscopic uni-axial compressive strengths are qualitatively consistent with experimental results in terms of water-cement ratio and material age.
  • Toyoharu Nawa, Kiyofumi Kurumisawa
    ADVANCES IN CONCRETE STRUCTURAL DURABILITY: PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE ON DURABILITY OF CONCRETE STRUCTURES ICDCS2010 211 - 217 2010 [Refereed][Not invited]
     
    Sustainable development is a major driver for future innovations and prospects for development of new construction materials with lower environmental impact. The use of industrial by-products in construction is very favourable to the sustainable development of our modem society. This article presents the situation of the sustainable recycling system of construction in Japan; In 2007 Japanese cement industry produced about 50 million tons of cement, and also used about 27 million tons of waste and by-products as alternative raw materials and fuel. Thus at present the construction industry can become the core of artificial ecosystem. Further eco-cement, which is made from municipal waste incineration ash and sewage sludge have been developed in Japan.
  • AOYAMA Takuto, KURUMISAWA Kiyofumi, NAWA Toyoharu, OWADA Hitoshi
    Cement Science and Concrete Technology 一般社団法人 セメント協会 64 (1) 66 - 73 0916-3182 2010 [Refereed][Not invited]
     
    Transport characteristic of cement based materials is close to pore structure. To evaluate transport characteristic of cement based materials which have been used for super-long term, the microstructure of cement based materials will be metamorphosed by exterior environment, so it is necessary to consider the microstructure of cement based materials. However, many prediction models of transport characteristic focus only on pore structure, there are few prediction models of transport characteristic that consider the spatial distribution of C-S-H, portlandite, and pore. Therefore, this study focuses on the spatial distribution of each phase of cement based materials. From the 2-D backscattered electron image, the auto-correlation function of each phase of cement based materials is calculated, and the 3-D spatial image of cement based materials is estimated by using the auto-correlation functions. We attempt to estimate diffusion coefficient of chloride ion from the 3-D spatial image. Estimated value of the diffusion coefficient of chloride ion from the 3-D spatial image is as half as the experimental value. And we attempt to estimate diffusion coefficient of the deteriorated sample from 3-D spatial image of normal sample. There is a difference within 10 times between the estimated value from the 3-D spatial image of the normal sample and the experimental value of the deteriorated artificially sample.
  • FUKUSHIMA Koki, ISHIMORI Masatoshi, KURUMISAWA Kiyofumi, NAWA Toyoharu
    Cement Science and Concrete Technology 一般社団法人 セメント協会 64 (1) 74 - 81 0916-3182 2010 [Refereed][Not invited]
     
    Dry and wet cycle experiment was carried out on hardened cement paste to understand the drying shrinkage mechanism and the effect of Shrinkage Reducing Agent（SRA）on the pore size distribution determined by Low Temperature Thermo Porosimetry（LT-DSC）. In the specimen without SRA which was held at 20 degrees Celsius and relative humidity of 40％, the volume of Small Gel Pore（1.0 to 2.2 nm in radius）was reduced but it did not recover after dry and wet cycle experiment, while the volume of Large Gel Pore（2.2 to 6.0 nm in radius）did not change. Therefore, it could be clear that at this condition the main factor of the shrinkage and expansion was aggregation and dispersion of the C-S-H unit. On the other hand, in the specimen without SRA which was held at 40 degrees Celsius and relative humidity of 40％, the volume of C-S-H Gel Pore（1.0 to 6.0 nm in radius）was reduced but it did not recover after dry and wet cycle experiment, the pore structure became coarse and the volume of capillary pore increased. Thus, it could be clear that at this condition, the main factor of the shrinkage and expansion was aggregation and dispersion of the cluster of C-S-H. In contrast, in the specimen with SRA, the pore size distribution did not change after dry and wet cycle experiment. Therefore, it could be clear that SRA retain the C-S-H Gel Pore which contributes the shrinkage and expansion to reduce strain after dry and wet cycle experiment.
  • KURUMISAWA Kiyofumi, NAWA Toyoharu
    Journal of Structural and Construction Engineering (Transactions of AIJ) 日本建築学会 74 (642) 1405 - 1405 1340-4202 2009/08 [Refereed][Not invited]
     
    For achievement of long-term durability of concrete structures, it is important to get knowledge about properties of concrete. Nowadays, properties of concrete are determined by experimental or predicting from empirical equation. However, it is difficult to predict concrete properties at long-term, because it is impossible to do experiment. Therefore, it is necessary to make a model by considering its microstructure. Microstructure is a key for predicting the properties of concrete. Some properties are determined by microstructure such as C-S-H, calcium hydroxide, pores, unhydrated cement particles, interfacial transition zone and these interactions. In this study, we investigated dynamic elastic modulus of hardened cement pastes in view point from microstructure. Backscattered electron image was used for acquiring the microstructure image and autocorrelation function (ACF) of each phase was calculated by these images. The ACF was applied for reconstructing three dimensional structures from two dimensional images. Finally, three dimensional structures were used for calculating dynamic elastic modulus of specimen. It was cleared that the prediction result of dynamic elastic modulus used micro indentation result was good agreement with experimental result in high W/C.
  • Y. Elakneswaran, T. Nawa, K. Kurumisawa
    CEMENT AND CONCRETE RESEARCH 39 (4) 340 - 344 0008-8846 2009/04 [Refereed][Not invited]
     
    in this study, surface charge mechanism of cement hydrates and its relations to adsorption of chloride ions are investigated. Hydrated cement paste (HCP) shows net positive surface charge by dissociation and adsorption. In HCP, chlorides bind as Friedel's salt (chemical binding) as well as adsorb on the surface of hydrates (physical binding). A surface complexation model is used to predict the adsorption of chlorides on calcium silicate hydrates (C-S-H). A good agreement between experimental and predicted chloride adsorption isotherm clearly demonstrate that the chlorides adsorb on the surface of C-S-H and bringing additional negative surface charge (SiOHCl(-)). However, chloride ions neutralize the positively charged surfaces of portlandite and Friedel's salt by physical adsorption. From the results, it can be concluded that C-S-H is the dominant phase in terms of chloride adsorption in HCP. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.
  • Y. Elakneswaran, T. Nawa, K. Kurumisawa
    MATERIALS AND STRUCTURES 42 (1) 83 - 93 1359-5997 2009/01 [Refereed][Not invited]
     
    The amount of free chloride content in concrete is one of major factors in initiating the corrosion process. The material and environmental factors play a key role in diffusing the chloride ion through the cover concrete to reinforcement. Thus, the electrochemical study is indispensable to understand the mechanism of chloride ingress into concrete. Determination of surface charge and its influence on diffusion of chloride ion into cement matrix of concrete are researched for Ordinary Portland Cement (OPC) paste and cement paste containing Ground Granulated Blastfurnace Slag (GGBS). Different kinds of experiments such as measurement of membrane potential, determination of porosity and pore size distribution, determination of pore solution concentration, and steady state diffusion coefficient of chloride and sodium ions are employed to understand the mechanism of chloride ingress. The obtained results show that the positive surface charge on the pore walls of hardened paste regardless of GGBS's presents. The surface charge of hardened paste mainly depends on pore solution concentration and cement composition. The physiochemical characteristics of the pores are affecting on transporting ions through it. Hardened paste has greater resistance to diffusing sodium ions than chloride ions. Moreover, there is a strong interaction between transport of chloride ion and surface charge in matured hardened paste.
  • Y. Elakneswaran, T. Nawa, K. Kurumisawa
    CEMENT & CONCRETE COMPOSITES 31 (1) 72 - 76 0958-9465 2009/01 [Refereed][Not invited]
     
    Electrokinetic studies of interfaces between solid phase and aqueous solution have most often been undertaken to elucidate the mechanism of adsorption and transport of different species into cementitious materials. The zeta potential is used to understand the electrokinetic properties of interfaces. In the present paper, zeta potential studies of cements and paste, with and without addition of slag, in different electrolyte solutions are carried out to understand the effect of the adsorption of charged species. The amounts of adsorbed ions are also measured to verify the results obtained by zeta potential measurement. This study shows that the cements and paste particles are negatively charged in water, sodium chloride solution, and at low concentration of calcium. At high concentration of calcium a charge inversion is observed. Thus, both calcium and chloride are potential determining ions, whereas sodium behaves as an indifferent ion. Moreover, slag particles strongly influence the surface chemistry not just of the slag but of the whole paste. Crown Copyright (c) 2008 Published by Elsevier Ltd. All rights reserved.
  • 胡桃沢 清文
    日本コンクリート工学年次論文集 31 (1) 499 - 504 2009 [Refereed][Not invited]
  • 胡桃沢 清文
    日本コンクリート工学年次論文集 31 (1) 109 - 114 2009 [Refereed][Not invited]
  • 胡桃沢 清文
    日本コンクリート工学年次論文集 31 (1) 589 - 594 2009 [Refereed][Not invited]
  • KAWAKAMI Hiroyuki, NAWA Toyoharu, KURUMISAWA Kiyofumi, MINATO Daisuke
    Cement Science and Concrete Technology 一般社団法人 セメント協会 63 (1) 35 - 42 0916-3182 2009 [Refereed][Not invited]
     
    It has been recognized that the hydration behavior of Belite depends on the amount of Alite being coexistence with Belite, the curing temperature and the ionic concentration of leached calcium in pore solution. To understand these crucial factors on the hydration behavior of Belite, X-ray diffraction（XRD）and Rietveld analysis are carried out to quantify the hydration degree of Alite, Belite, and other cement hydrates. From the result obtained in this study, it is found that the amount of Alite has an influence on the hydration behavior of Belite；hydration degree of Belite decreases with increase in the amount of Alite. Furthermore, curing temperature（less than 50℃）does not have an affect the hydration behavior of α dicalcium silicate（α-C2S）but the hydration behavior of β dicalcium silicate（β-C2S）has temperature dependency. At high water to cement ratio of 10,000 percent, the ionic concentration of calcium in pore solution remains very low, and it brings about that the hydration degree of Alite stops at around 80％ and the induction period is disappeared；however, there is no significant different on the hydration behavior of β-C2S from that at water to cement ratio of 50％. Therefore it might be concluded that the hydration behavior of β-C2S is not affected by the ionic concentration of calcium in pore solution.
  • KURUMISAWA Kiyofumi
    セメントコンクリート セメント協会 (741) 56 - 59 0371-0718 2008/11/10 [Not refereed][Not invited]
  • ELAKNESWARAN Yogarajah, NAWA Toyoharu, KURUMISAWA Kiyofumi, HAYASHI Ami
    セメント・コンクリート論文集 (61) 108 - 114 0916-3182 2008/02/20 [Refereed][Not invited]
  • Micro elastic modulus of blended cement pastes
    Proceedings of the 8th international conference on creep, shrinkage and durability mechanics of concrete structures 103 - 108 2008 [Not refereed][Not invited]
  • XRDリートベルト法によるカルシウムシリケート相の水和解析
    セメント・コンクリート論文集 (62) 39 - 46 2008 [Refereed][Not invited]
  • エコセメント硬化体の強度発現に関する一考察
    セメント・コンクリート論文集 (62) 47 - 53 2008 [Not refereed][Not invited]
  • セメント硬化体の微細構造と弾性挙動
    日本コンクリート工学年次論文集 30 (1) 591 - 596 2008 [Not refereed][Not invited]
  • 空隙構造の異なるセメント硬化体の微細構造と動弾性係数
    セメント・コンクリート論文集 (62) 122 - 127 2008 [Not refereed][Not invited]
  • KURUMISAWA Kiyofumi, NAWA Toyoharu, NARA Yoshitaka
    Proceedings of the Japan Concrete Institute 日本コンクリート工学協会 30 (1) 591 - 596 1347-7560 2008 [Not refereed][Not invited]
     
    セメント硬化体の弾性挙動を予測することは超長期のコンクリート構造物の劣化予測を行う上で非常に重要である。しかしながら,その挙動の解析は現在までメゾからマクロの範囲において精力的に行われてきたため,ミクロで生じる物性の変化に対応するものではなかった。そこで本研究では弾性挙動の解析をミクロレベルから行うことを目的とした。そのための手法として反射電子像による硬化体中の各相の同定,インデンテーション法による各相の弾性係数の測定を行い,その結果をマクロな物性であるセメント硬化体の弾性係数と関連付けた。その結果,弾性係数は水和生成物量に大きく依存していることを明らかにした。
  • 胡桃澤 清文, 蛭川 泰卓, 名和 豊春
    Proceedings of the Japan Concrete Institute 公益社団法人日本コンクリート工学会 29 (1) 63 - 68 1347-7560 2007/07/30 [Refereed][Not invited]
     
    エコセメント(EC)に混和材(フライアッシュFA,高炉スラグ微粉末BFS)を混和した際の長期強度発現性に及ぼす微細構造の影響を明らかにするために,圧縮強度と微細構造を測定する方法として水銀圧入法,反射電子像による画像解析の適用を行った。その結果,FAとBFSを混和した試験体は長期材齢においても強度発現が見られ,材齢1年においてはECの強度よりも高い結果が得られた。また,水銀圧入の結果からも混和材を入れた試験体において総細孔量が減少し,緻密な微細構造が形成されECとは異なる構造形成がなされ,FA及びBFSの混和によりECの長期強度発現の伸びは改善されることが示された。
  • ELAKNESWARAN Yogarajah, NAWA Toyoharu, KURUMISAWA Kiyofumi, FUSHIMI Koji
    セメント・コンクリート論文集 (60) 111 - 117 0916-3182 2007/02/20 [Refereed][Not invited]
  • Influence of membrane potential on the diffusion of chloride ion in the paste
    12th international congress on the chemistry of cement CDROM  2007 [Not refereed][Not invited]
  • Effects of surface improvement agent composed of Lithium silicate on permeability and durability of hardened concrete
    12th international congress on the chemistry of cement CDROM  2007 [Not refereed][Not invited]
  • エコセメントペーストの微細構造形成に及ぼす各種混和材料の影響
    コンクリート工学年次論文報告集 CDROM  2007 [Not refereed][Not invited]
  • Strength development and its microstructure of ECO-cement paste
    12th internatinal congress on the chemistry of cement CDROM  2007 [Not refereed][Not invited]
  • 胡桃澤清文
    セメント・コンクリート論文集 61 印刷中 - 107 2007 [Not refereed][Not invited]
  • XRD‐リートベルト法によるエコセメントペーストの水和性状解析
    セメント・コンクリート論文集 印刷中  2007 [Not refereed][Not invited]
  • 濱 幸雄, 胡桃澤 清文, 谷口 円, 桂 修
    Proceedings of the Japan Concrete Institute 日本コンクリート工学会 29 (1) 819 - 824 1347-7560 2007 [Not refereed][Not invited]
     
    本研究では,高分子温湿度センサーを埋め込んだコンクリートを札幌,旭川,室蘭の3都市に2年間暴露してコンクリート内部の温湿度の経時変化を測定した。その結果から,コンクリート温度推定式の提案とその検証を行うとともに,冬期間の凍結融解作用時のコンクリート内部の相対湿度と凍結最低温度の関係,コンクリート温度と相対湿度を考慮した暴露地および部材による等価積算温度の違いについて検討した。
  • Pipat Termkhajornkit, Toyoharu Nawa, Kiyofumi Kurumisawa
    CEMENT & CONCRETE COMPOSITES 28 (9) 781 - 789 0958-9465 2006/10 [Refereed][Not invited]
     
    This paper explains the effect of water curing condition on compressive strengths of fly ash-cement paste by quantitative data of hydration degree. Hydration of fly ash-cement paste was estimated by Rietveld analysis and selective dissolution. The result shows that the hydration degree of belite is affected by water curing conditions, more so than that of fly ash and alite. Fly ash still continues to hydrate even without an extra, external supply of water. The strong dependence of fly ash-cement concrete on curing conditions does not come from the hydration degree of fly ash, but rather comes from the hydration degree of cement, especially belite. When the water to binder ratio is low enough, the hydration of cement plus small hydration of fly ash are considered to be enough for adequate compressive strength at the beginning. Then, compressive strength of fly ash-cement paste becomes less sensitive to the water curing period. (c) 2006 Elsevier Ltd. All rights reserved.
  • YAMASHIRO Yoichi, SAITO Toshiki, NAWA Toyoharu, KURUMISAWA Kiyofumi
    Summaries of technical papers of Annual Meeting Architectural Institute of Japan. A-1, Materials and construction 日本建築学会 2006 (2006) 271 - 272 1341-4437 2006/07/31 [Not refereed][Not invited]
  • 胡桃澤 清文, 名和 豊春
    コンクリート工学年次論文集 公益社団法人日本コンクリート工学会 28 (1) 1871 - 1876 1347-7560 2006/07/30 [Not refereed][Not invited]
     
    電磁波レーダは,その特性からコンクリート中に含まれる塩化ナトリウム量の測定にも利用可能であることが報告されている。筆者らは,既報において電磁波レーダにより硬化セメントペースト及びモルタルでその検討を行ったが,本報ではコンクリートにその手法を適用した。その結果,既報と同様に電磁波レーダによって得られた波形を周波数解析することによりコンクリート中の塩化ナトリウム量の違いを明らかにすることができた。また,1%の塩化ナトリウムが表層部の1cmの厚さに含まれている場合においても周波数解析を受信波形に行うことによってその違いを明らかにすることができた。
  • NAWA T., KURUMISAWA K.
    コンクリート工学 = Concrete journal 日本コンクリート工学協会 44 (5) 31 - 34 0387-1061 2006/05/01 [Not refereed][Not invited]
  • K Kurumisawa, K Tanaka
    CEMENT AND CONCRETE RESEARCH 36 (2) 330 - 336 0008-8846 2006/02 [Refereed][Not invited]
     
    It is widely known that the pore structure of concrete strongly influences its physical properties. Therefore, we developed a technique for the visualization of the pore structure because of clearing it correctly. However, this visualization is limited to two-dimensional imaging for sections of the specimen. As a result, in this study, we developed a technique for reconstructing the acquired 2D images of the pore structure into 3D form by stacking them. By using this image, the relationship between water permeability and pore connectivity was clarified, and it was shown clearly that the pore connectivity strongly affects the water permeability. (c) 2005 Elsevier Ltd. All rights reserved.
  • 胡桃澤 清文, 名和 豊春
    Proceedings of the Japan Concrete Institute 日本コンクリート工学協会 28 (1) 1871 - 1876 1347-7560 2006 [Not refereed][Not invited]
     
    電磁波レーダは,その特性からコンクリート中に含まれる塩化ナトリウム量の測定にも利用可能であることが報告されている。筆者らは,既報において電磁波レーダにより硬化セメントペースト及びモルタルでその検討を行ったが,本報ではコンクリートにその手法を適用した。その結果,既報と同様に電磁波レーダによって得られた波形を周波数解析することによりコンクリート中の塩化ナトリウム量の違いを明らかにすることができた。また,1%の塩化ナトリウムが表層部の1cmの厚さに含まれている場合においても周波数解析を受信波形に行うことによってその違いを明らかにすることができた。
  • 胡桃澤 清文
    セメント・コンクリート論文集 60 (60) 142 - 148 2006 [Not refereed][Not invited]
  • XRDリートベルト法によるエコセメントの水和解析
    セメント・コンクリート論文集 (60) 134 - 141 2006 [Not refereed][Not invited]
  • KURUMISAWA Kiyofumi, TERMKHAJORNKIT Pipat, NAWA Toyoharu
    Journal of Structural and Construction Engineering (Transactions of AIJ) 日本建築学会 71 (603) 1 - 7 1340-4202 2006 [Not refereed][Not invited]
     
    Recently, the amount of the exhaust of fly ash increases by increasing thermal power plant. Using it as a concrete mixture material is an effective method for decreasing waste. However, the influence on the hydration of the cement and reaction rate of fly ash is not examined in detail. Then, the cement paste that mixed fly ash examined it by Backscattered Electron image and element image measured by Energy Dispersive X-ray analysis in this research. As a result, reaction rate of fly ash and distribution of fly ash and cement in the fly ash-cement pastes were clarified. And the amount of composition in fly ash cement paste was cleared.
  • KURUMISAWA Kiyofumi, TERMKHAJORNKIT Pipat, NAWA Toyoharu
    Journal of Structural and Construction Engineering (Transactions of AIJ) 日本建築学会 71 (603) 9 - 15 1340-4202 2006 [Not refereed][Not invited]
     
    The elastic properties of concrete depend on the characteristic of cement matrix and coarse aggregates. The elastic characteristic of cement matrix depends on the cement paste when the properties of the fine aggregate are constant. That is, clarifying the characteristic of the cement matrix clarifies the elastic properties of concrete. Therefore, the technique for predicting the elastic modulus of the cement paste from the viewpoint of microstructure was examined in this research. It classified into four phases (pore, C-S-H, calcium hydroxide, and unhydrated cement) in the backscattered electron image, and examined it by the finite element method in two dimension. The result indicates the elastic modulus of hardened cement paste strongly depends on the porosity of large pores. Moreover, it is cleared that the elastic modulus hardly changes by differences of the number of pixels and the magnification of images in this study.
  • 電磁波レーダーによるコンクリート中の塩分量推定の検討
    コンクリート工学年次論文集 28 (1) 1871 - 1876 2006 [Not refereed][Not invited]
  • Effect of GGBS on Membrane Potential of Pastes
    Y. Elakneswaran, T. Nawa, K. Kurumisawa, K. Fushimi
    RILEM Proceedings PRO 46, Concrete Durability and Service Life Planning (ConcreateLife’06) 405 - 414 2006 [Refereed][Not invited]
  • TERMKHAJORNKIT PIPAT, NAWA TOYOHARU, KURUMISAWA KIYOFUMI
    コンクリート工学年次論文集 27 (1) 169 - 174 1347-7560 2005/06/25 [Refereed][Not invited]
  • KURUMISAWA Kiyofumi, NAWA Toyoharu
    Journal of Structural and Construction Engineering (Transactions of AIJ) 日本建築学会 70 (595) 9 - 15 1340-4202 2005 [Not refereed][Not invited]
     
    The durability of concrete is greatly influenced by the physical properties of the hardened cement paste. The physical properties of hardened cement paste are dependent on the degree of hydration and porosity of hardened cement paste. Therefore, it is important to measure the degree of hydration and porosity of hardened cement paste correctly. Measuring them, some methods are proposed, XRD, point counting or TG/DTA as example. Then, in this research, with Backscatter electron image (BEI) and Energy dispersive X-ray analysis (EDX), the degree of hydration and porosity of hardened cement paste are measured, and clarifying the distribution of the composition. By using BEI and EDX together, as a result of applying the method, the degree of hydration and porosity of hardened cement paste were clarified and the distribution of a compound was clarified further.
  • コンクリート工学年次論文集 27 (1) 1771 - 1776 2005 [Refereed][Not invited]
  • 胡桃澤 清文
    セメント・コンクリート論文集 (59) 38 - 44 2005 [Refereed][Not invited]
  • 胡桃澤 清文, 名和 豊春
    コンクリート工学年次論文集 日本コンクリート工学協会 27 (1) 1771 - 1776 1347-7560 2005 [Not refereed][Not invited]
     
    コンクリート構造物の耐久性を評価する上で,コンクリートの劣化の程度を測定することは重要である。特に鉄筋の腐食を考慮したとき,その劣化を促進する塩化ナトリウム含有量を正確に測定することが求められる。そこで本研究では,塩化ナトリウム含有量を非破壊で測定することができる方法の1つとして電磁波レーダーに着目して検討を行った。その結果,電磁波レーダーの受信波形を周波数解析することにより塩化ナトリウム含有量の推定は可能であることを示した。また,FDTD法(Finite-difference time-domain)を用いて,いくつかの条件下での電磁波の伝播特性について検討を行い,その特性を明らかにした。
  • TERMKHAJORNKIT Pipat, NAWA Toyoharu, KURUMISAWA Kiyofumi
    Proceedings of the Japan Concrete Institute 日本コンクリート工学協会 27 (1) 169 - 174 1347-7560 2005 [Not refereed][Not invited]
  • KURUMISAWA Kiyofumi, TANAKA Kyoji
    Journal of Structural and Construction Engineering (Transactions of AIJ) 日本建築学会 69 (584) 23 - 28 1340-4202 2004 [Not refereed][Not invited]
     
    It is well known that most of property of concrete is influenced by its pore structure. ln particularly permeability of concrete is dependent on its pore structure. Therefore, it is beneficial to know durability of concrete that pore structure is measured exactly. We already developed the technique to make clear the pore structure in hardened cement paste by gallium intrusion and the following EPMA observation. In this research, using a image acauired by EPMA estimates diffusion coefficient with random walk which is many particles are walking in pore structure with random. The permeability of NaCl solution is measured by method of diffusion cell. Relationship between permeability of NaCI solution and pore structure by measuring gallium intruded method is discussed. As a result, pore connectivity and permeability is closely relationship.
  • KURUMISAWA Kiyofumi, TANAKA Kyoji
    Journal of Structural and Construction Engineering (Transactions of AIJ) 日本建築学会 67 (556) 9 - 14 1340-4202 2002 [Not refereed][Not invited]
     
    It is widely known that the property of concrete is influenced by its pore structure, particularly permeability of concrete is directly dependent on it. We have already developed the technique to make clear the pore structure in hardened cement paste by applying gallium intrusion technique and the following EPMA observation. However, this method has only limited to 2 dimensional analysis. We improve the technique to 3 dimensional analysis of pores by stacking up 75 sheets of 2-D pore image pictures. In this paper, 3-D pore image is made up and pore distribution, shape and continuity of various hardened cement paste were discussed.
  • Tanaka, K., Kurumisawa, K.
    Cement and Concrete Research 32 (9) 1435 - 1441 0008-8846 2002 [Refereed][Not invited]
  • 胡桃澤 清文, 田中 享二
    コンクリート工学年次論文集 公益社団法人日本コンクリート工学会 23 (2) 781 - 786 1347-7560 2001/06/08 [Not refereed][Not invited]
     
    セメントペーストの空隙構造は打ち込み方向から表層部、中層部、下層部によって大きく違うことが予想される。一般的に表層部の構造は粗いといわれているがどのような構造の差であるかをガリウム圧入法で測定、EPMA測定により画像化しさらに定量的評価を行った。その結果、表層部では大きくその構造は他の部位とは異なり粗い構造であることが明らかになった。またその表層部の構造を材齢7日と28日を比較したとき、材齢28日経過した後でもそれほど改善されないことが画像から明らかとなった。
  • 胡桃澤 清文, 田中 享二
    コンクリート工学年次論文報告集 23 (2) 781 - 786 1340-4741 2001/06/08 [Not refereed][Not invited]
  • 胡桃澤 清文, 田中 享二
    コンクリート工学年次論文報告集 日本コンクリート工学協会 23 (2) 781 - 786 1340-4741 2001/06/08 [Not refereed][Not invited]
     
    セメントペーストの空隙構造は打ち込み方向から表層部、中層部、下層部によって大きく違うことが予想される。一般的に表層部の構造は粗いといわれているがどのような構造の差であるかをガリウム圧入法で測定、EPMA測定により画像化しさらに定量的評価を行った。その結果、表層部では大きくその構造は他の部位とは異なり粗い構造であることが明らかになった。またその表層部の構造を材齢7日と28日を比較したとき、材齢28日経過した後でもそれほど改善されないことが画像から明らかとなった。
  • KURUMISAWA Kiyofumi, TANAKA Kyoji
    セメント・コンクリート論文集 54 654 - 659 0916-3182 2001/02/10 [Not refereed][Not invited]
  • KURUMISAWA Kiyofumi, TANAKA Kyoji
    Journal of Structural and Construction Engineering (Transactions of AIJ) 日本建築学会 66 (544) 1 - 6 1340-4202 2001 [Not refereed][Not invited]
     
    To understand the property of concrete, the knowledge about pore structure of hardened cement is important, particularly in early age of a few weeks, because the pore structure change by active hydration. In the paper, the change of pore structure in early age was investigated by observation of pores through gallium intrusion method developed by the authors and EPMA analysis. As the technique is limited to 2-dimensional analysis, the simulation of hydration developed by Bentz was furthermore carried outto obtain 3-dimensional information about pore structure. It was quantitatively made clear that the value of pore and the number of continuous pores rapidly decreased in early age.
  • 硬化途中におけるセメントペーストの空隙構造の変化
    日本建築学会構造系論文集 1 - 6 2001 [Not refereed][Not invited]
  • KURUMISAWA Kiyofumi, TANAKA Kyoji
    Proceedings of the Japan Concrete Institute 公益社団法人日本コンクリート工学会 22 (2) 691 - 696 1347-7560 2000/06/01 [Not refereed][Not invited]
     
    コンクリートの物性を理解する上で,現在はセメント硬化体の細孔構造を測定する方法として水銀圧入法が広く利用されている。しかしこの測定法は細孔量および細孔径ごとの分布を測定することが出来るが,細孔の形態及びその位置を得ることができない。本研究では水銀圧入法では得ることが出来ないこれらの情報を知る測定法を開発し,セメント硬化体の細孔構造を可視化することを試みた。さらにその測定法を用いて各種条件下におけるセメント硬化体の細孔構造の変化を画像として明らかにすることを行った。
  • KURUMISAWA Kiyofumi, TANAKA Kyoji
    コンクリート工学年次論文報告集 日本コンクリート工学協会 22 (2) 691 - 696 1340-4741 2000/06/01 [Not refereed][Not invited]
     
    コンクリートの物性を理解する上で,現在はセメント硬化体の細孔構造を測定する方法として水銀圧入法が広く利用されている。しかしこの測定法は細孔量および細孔径ごとの分布を測定することが出来るが,細孔の形態及びその位置を得ることができない。本研究では水銀圧入法では得ることが出来ないこれらの情報を知る測定法を開発し,セメント硬化体の細孔構造を可視化することを試みた。さらにその測定法を用いて各種条件下におけるセメント硬化体の細孔構造の変化を画像として明らかにすることを行った。
  • TANAKA Kyoji, KURUMISAWA Kiyofumi
    Journal of Structural and Construction Engineering (Transactions of AIJ) 日本建築学会 65 (532) 21 - 26 1340-4202 2000 [Not refereed][Not invited]
     
    A mercury intrusion technique has been widely used to measure micro pores in porous materials. However, the information of shapes and locations of pores are not able to get through the measurement. A new technique for directly observing pores, in which gallium of liquid state is pressed into pores at higher temperature of its transformation temperature of 29.8℃ and then solidified by cooling down, was developed to measure them. The technique was applied to cement paste. The picture image of distribution of solidified gallium was observed through an electron probe micro analyzer (EPMA), and the shapes and locations of pores in cement paste were discussed.
  • ガリウムを用いた空隙観察手法の開発と他方法との比較
    セメント・コンクリート論文集 (54) 654 - 659 2000 [Not refereed][Not invited]
  • セメント硬化体の空隙構造の画像化
    コンクリート工学年次論文集 22 (2) 691 - 696 2000 [Not refereed][Not invited]
  • セメント硬化体の空隙観察手法の開発
    日本建築学会構造系論文集 21 - 26 2000 [Not refereed][Not invited]
  • ABE Shinya, TANAKA Kyoji, KURUMISAWA Kiyofumi
    セメント・コンクリート論文集 53 (0) 928 - 933 0916-3182 1999/12/25 [Not refereed][Not invited]

Conference Activities & Talks

MISC

Awards & Honors

  • 2023/09 公益財団法人 鉄鋼環境基金 第１４回(2023 年度)助成研究成果表彰 理事長賞
     高炉スラグ固化体作製のための高炉スラグの反応促進技術の開発
  • 2011 第39回セメント協会論文賞
  • 2004 博士論文賞

Research Grants & Projects

  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    Date (from‐to) : 2021/04 -2024/03 
    Author : 胡桃沢 清文
     
    コンクリート製造時には多くのセメントを使用することからセメント製造時のCO2排出は避けらることができない。そこでセメントの一部を高炉スラグ微粉末やフライアッシュに置換した混合セメントコンクリートのさらなる利用が求められている。混合セメントコンクリートは長期的には普通コンクリートと同等の性能を示すが、初期強度発現がセメントのみと比べると低く、施工期間が長期化するためさらなる利用が制限されている。そのため混合セメントコンクリートの初期反応を活性化させ強度発現を促す混和剤の開発が求められている。そこで本研究では混合セメント中の高炉スラグ微粉末やフライアッシュの初期反応を活性化させる硬化促進剤の開発を行った。特に本年度においては無機塩が高炉スラグやフライアッシュの反応に及ぼす影響に関して開発を行った。高炉スラグとフライアッシュの反応性を明らかにするために水酸化カルシウムを刺激剤とする硬化体の作製を行った。さらに硬化促進剤の混和材への作用メカニズムを選択溶解法や固体NMRを用いて微視的視点から明らかにした。また、強度発現、拡散性能、収縮特性に関して硬化促進剤を加えた試験体に関して検討をおこなった。その結果、無機塩を加えた試料では強度発現が促進された。高炉スラグやフライアッシュの反応は、イオンの移動速度が反応促進に大きく影響を及ぼすことを明らかにした。また、高炉スラグやフライアッシュの溶解に伴いアルミネート系の水和物が初期の強度発現に影響を及ぼすことを明らかにした。
  • 水分状態に基づく混合セメントコンクリートの凍害劣化予測モデルの構築
    鹿島学術振興財団研究助成
    Date (from‐to) : 2022 -2023
  • 流動性と収縮特性を改善したメタカオリンジオポリマーの開発
    前田記念工学振興財団研究助成
    Date (from‐to) : 2022
  • ジオポリマーコンクリートのナノ構造解析手法の開発
    大成学術財団 2022年度研究助成
    Date (from‐to) : 2022
  • 細孔内水分状態に基づく高耐久性メタカオリンジオポリマーの開発
    (公財)大林財団 2022年度研究助成
    Date (from‐to) : 2022
  • 高炉スラグ固化体作製のための高炉スラグの反応促進技術の開発
    鉄鋼環境基金環境助成研究
    Date (from‐to) : 2019 -2021
  • ジオポリマー技術による人工バリア構築のための基礎的検討
    放射性廃棄物に係る重要な基礎的技術に関する研究調査の支援等に関する業務
    Date (from‐to) : 2018 -2020
  • 無機・有機混和剤による高炉スラグ微粉末の反応促進
    前田記念工学振興財団研究助成
    Date (from‐to) : 2020
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2016/04 -2019/03 
    Author : Nawa Toyoharu, Nishi Hironobu
     
    In this study, we aimed to evaluate initial strength development and scaling resistance of blast furnace slag cement concrete using accelerator and frost damage inhibitor. As a result, it has been clarified that the scaling resistance is improved in blast furnace slag cement concrete added with an appropriate amount of air and a frost damage inhibitor. In addition, it has been confirmed that the development of the initial strength of blast furnace slag cement concrete using a nitrite-based accelerator is improved. From above mentioned, it was possible to clarify from this study that the combination of accelerator and frost damage inhibitor can improve the initial strength development and the scaling resistance of blast furnace slag cement concrete.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2016/04 -2019/03 
    Author : Kurumisawa Kiyofumi
     
    I developed a method to measure the pore structure of concrete. There are many pores in concrete, and their compressive strength and transport properties differ depending on pore size distribution. Therefore, it is very important to clarify the pore size distribution in concrete. Pore size distribution is clarified by the thermoporometry method of measuring the amount of pore from the heat quantity generated during freezing and thawing of the water present inside the pore, and the proton NMR measurement focusing on the mobility of hydrogen. It became clear by this method that the distribution of the water present in the pore is greatly different between blended cement paste and ordinary cement paste.
  • 初期反応性を高めた高炉スラグ固化体の創製
    (公財)大林財団 2019年度研究助成
    Date (from‐to) : 2019
  • 寒冷地におけるジオポリマー硬化体の製造技術の開発
    北海道ガス大学研究支援制度
    Date (from‐to) : 2019
  • 空隙水の存在状態に基づく混合セメント硬化体の空隙構造の解明と拡散性能評価
    日本コンクリート工学会研究助成
    Date (from‐to) : 2018
  • プロトンNMRによる混合セメントコンクリートの凍害発生メカニズムの解明
    公益財団法人 LIXIL住生活財団調査研究助成
    Date (from‐to) : 2017
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows
    Date (from‐to) : 2014/04 -2016/03 
    Author : 胡桃沢 清文, JAMSHIDI ALI, JAMSHIDI Ali
     
    昨年度行ったモルタルの圧縮強度と弾性係数の実験結果に基づき異なる2種類のコンクリート舗装についての設計を行い、同時に養生温度の影響についても検討を行った。使用した産業副産物の種類、混和量、養生条件について燃料消費と温暖化ガスの排出の観点から分析を行った。原材料の製造過程、練り混ぜ、打ち込みのすべてに関して高速道路と滑走路のコンクリート舗装に関して検討を行った。特に原材料製造過程においては、セメント、フライアッシュ、高炉スラグ微粉末、水、鉄筋のすべてについて考慮した。コンクリート舗装の構造性能の設計に関しては、アメリカの基準であるAASHTOの設計手法に従って行った。また、滑走路の舗装に関しては、ボーイング787を想定した設計を行った。その結果、養生温度の上昇はほとんどの場合、舗装スラブの厚さを低減することが可能であることを明らかにした。そしてフライアッシュや高炉スラグ微粉末などの産業副産物を使用した舗装は構造性能の観点から混和していない舗装と比較して同程度もしくはそれ以上の性能を示すことを明らかにした。また、高温養生においては製造時にエネルギーを多く消費するが、舗装の供用期間を考慮すると総エネルギーは減少することを示した。 さらに建設時の遅延の影響について検討を行った。これは養生温度を上昇させる際の環境負荷を検討したものであり、この結果、高速道路と滑走路の舗装建設が遅延した場合には多くのエネルギー消費が増加することを定量的に示した。以上より産業副産物の利用や、養生温度の違いなどを環境負荷の観点と構造性能を合わせて定量的に評価するモデルを構築することができた。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2013/04 -2016/03 
    Author : Kurumisawa Kiyofumi
     
    In this study, the effect of microstructure on transport properties of hardened cement paste was investigated. Hardened cement paste mixed with inorganic electrolytes, blast furnace slag, and fly ash was investigated, and it was found that Calcium silicate hydrate(C-S-H) and pore solution composition had an influence on the transport properties as well as pore structure. The chloride adsorption ability of the hardened cement paste during calcium leaching decreased remarkably in comparison with before leaching, and it was clarified that the adsorption ability of C-S-H is depended on the Ca/Si ratio of C-S-H in the blended cement.
  • 科学技術振興機構：産学が連携した研究開発成果の展開 研究成果展開事業 マッチングプランナープログラム
    Date (from‐to) : 2016 -2016 
    Author : 胡桃沢 清文
  • 熱力学相平衡を考慮した混合セメント硬化体の物質移動モデルの構築
    鹿島学術振興財団研究者交流援助助成
    Date (from‐to) : 2016
  • ジオポリマー技術によるコンクリートのCO2排出低減化
    大林財団研究助成
    Date (from‐to) : 2016
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
    Date (from‐to) : 2012/04 -2014/03 
    Author : NAWA Toyoharu, KURUMISAWA Kiyofumi
     
    When industrial waste is utilized as the raw material for cement, C3A, which is a mineral of four major constitutes of cement increases because the industrial waste condenses high amount of aluminum. In this study, the hydration behavior of C3A, of which hydration rate is very fast, was in- vestigated by using a high-speed, ultra-sensitive XRD in combination of amorphous phase analysis with 27Al MAS NMR, and elucidated the reaction mechanism of C3A in more detail using thermodynamic phase equilibri-um and surface complexation models. The change in properties of C-S-H formed by the hydration reaction of C3S with the increase of Al content in the cement was also analyzed by using 29Si MAS NMR. In addition, the influence of increase of C3A content on the fluidity of cement paste was also investigated to evaluate the limitation of industrial waste usage in cement production.
  • 比抵抗測定によるかぶりコンクリートの物質移動特性評価
    戸田育英財団研究助成金
    Date (from‐to) : 2014
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2011 -2012 
    Author : KURUMISAWA Kiyofumi
     
    The purpose of this study is to predict the transport of ion in the hardened cement paste that calcium leaching occurred quantitatively. Furthermore, the mass transfer prediction model was improved by incorporating the phase equilibrium of solid-liquid interaction and3-dimensional spatial image model. As a result, it is possible to predict the transport of ion by the proposed prediction model. The AC impedance method that is simple and non-destructive measurement was applied to measure the transport properties of hardened cement paste, it is clarified that the relationship between the measured conductivity by AC impedance and diffusion coefficient of hardened cement paste was in good agreement.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2010 -2012 
    Author : NAWA Toyoharu, KURUMISAWA Kiyofumi, ASAMOTO Singo
     
    For technological development of shrinkage cracking suppression in cold climates, we have elucidated the frost damage degradation mechanisms and drying shrinkage reduction of shrinkage reducing agent, and developed a new shrinkage reducing agent (SRA) with improved freeze-thaw resistance. In addition, our shrinkage reducing agents had been optimized the molecular structure of shrinkage reducing agent according to an integrated model for the freezing and thawing action deterioration and drying shrinkage. In laboratory we examined the properties of fresh and hardened concrete such as workability, setting, mechanical properties, drying shrinkage, carbonation, rebar corrosion and the freeze-thaw resistance, and confirmed that the properties of SRA concrete were equivalent to those of concrete without SRA. Finally, we had also manufactured SRA concrete at ready-mixed concrete plant and fabricated in the actual structures, and confirmed that the performance of SRA concretes satisfied the target requirements.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2009 -2010 
    Author : KURUMISAWA Kiyofumi
     
    The section of the hardened cement paste was observed by a backscattered electron image to predict the properties of cementitious materials with mineral admixtures and quantified its microstructure by an autocorrelation function with the quantity of each phase. A three-dimensional image model was built by the supposition that each phase was distributed in the three-dimensional space in isotropic homogeneity based on them at random. Diffusion performance and mechanical properties of the hardened cement paste with this three-dimensional image model was calculated. As a result, about the diffusion performance, it was able to predict diffusivity of the hardened cement paste by using the value that it was based on a study in the past from the value that measured diffusivity of hydrates by micro-indentation method and estimated. In addition, the elastic modulus of hydrates was estimated from a stress-strain curve of the hardened cement paste reversely and it was shown that elastic modulus of hydrates is a function of the porosity and clarified that fracture criterion of hydrates was about 1,000μ regardless of curing age and the water cement ratio.
  • 多孔体のキャラクタリゼーション
    Date (from‐to) : 2008
  • 多孔体の3次元モデリング
    Date (from‐to) : 2008
  • Modelling of porous media
    Date (from‐to) : 2008
  • コンクリート構造物の耐久性
    Date (from‐to) : 2007
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2005 -2006 
    Author : 胡桃澤 清文
     
    本研究では、セメントの硬化過程における構造、構成化合物の組成がどのようなものであるかを視覚的に明らかにし、それぞれの組成が物性にどのような影響を与えるかについて検討を行った。 (1)普通、低熱、早強ポルトランドセメントの粉体から、それに含まれている構成化合物量の測定を行う手法を開発した。その手法は、反射電子像とエネルギー分散型X線分析により得られた元素分布像を組み合わせて解析することにより、エーライト、ビーライト、アルミネート及びフェライト相の分布及びそれらの量を明らかにするものである。その手法を用いた結果、以前から指摘されているようにボーグ式と異なる傾向を示し、本手法により直接的にセメントの構成化合物量の測定が可能であることが示された。 (2)(1)で提案した手法を用いて硬化セメントペーストを測定及び解析をした結果、強度発現には画像解析で測定可能な粗大な空隙が大きく影響を及ぼしていることを明らかにした。さらに未水和セメント粒子から水和反応率を測定することを可能とし、硬化セメントペースト中の水酸化カルシウム量、CSH量、空隙量、未水和セメント量を定量的に表すことを可能とした。 (3)また、画像解析から得られた水和セメントペースト中の相組成とXRDリートベルト法により測定した相組成では未反応セメント量はほぼ同じ値であり、セメント水和率に関してもほぼ同じ値であった。この傾向はエコセメントを用いた場合においても同様であることを確認した。 (3)定量的に明らかにしたそれぞれの組成からセメント硬化体中の塩分浸透性について検討した結果、同じ空隙率であればCSHゲルを含む水和生成物量が多いほど塩分浸透性は低下することを明らかにした。
  • リートベルト法によるセメント硬化体の構成化合物測定とコンクリート強度に与える影響
    セメント協会研究助成
    Date (from‐to) : 2005
  • 各種微粉末混和材の成分がセメント硬化体の微細構造及び水和率に与える影響と強度発現及び物質透過性との関係
    前田記念工学振興財団研究助成
    Date (from‐to) : 2005
  • セメント硬化体の微細構造とその物性
    Date (from‐to) : 1998

Educational Activities

Teaching Experience

  • Introduction to Informatics IIntroduction to Informatics I Hokkaido University
  • Advanced Information Processing for Resources Engineering
    開講年度 : 2021
    課程区分 : 修士課程
    開講学部 : 工学院
    キーワード : 化学反応　無機材料　モデリング　多孔体材料　サステイナブル社会 微分方程式
  • Advanced Information Processing for Resources Engineering
    開講年度 : 2021
    課程区分 : 修士課程
    開講学部 : 工学院
    キーワード : 化学反応　無機材料　モデリング　多孔体材料　サステイナブル社会 微分方程式
  • Advanced Information Processing for Resources Engineering
    開講年度 : 2021
    課程区分 : 博士後期課程
    開講学部 : 工学院
    キーワード : 化学反応　無機材料　モデリング　多孔体材料　サステイナブル社会 微分方程式
  • Exercise in Thermodynamics
    開講年度 : 2021
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : ガスサイクル、蒸気の性質、気液二相サイクル、熱移動
  • Introduction to Informatics I
    開講年度 : 2021
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 情報活用，情報社会，情報科学，プログラミング，データサイエンス
  • Numerical Computation
    開講年度 : 2021
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 2進数，誤差，反復法，ニュートン法，非線形方程式，連立方程式、ガウスの消去法，ＬＵ分解，反復法，ヤコビ法，ラグランジュ補間，台形公式，オイラー法，ルンゲ・クッタ法， 微分方程式，偏微分方程式
  • Thermodynamics
    開講年度 : 2021
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 熱、仕事、第一法則、第二法則、エントロピー、理想気体、熱機関、相平衡、化学平衡
  • Experiments for Sustainable Resources Engineering Ⅰ
    開講年度 : 2021
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 基本操作、物理計測、化学分析
  • Applied Mathematics I
    開講年度 : 2021
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 常微分方程式　ラプラス変換　フーリエ解析　偏微分方程式
  • Experiments for Sustainable Resources Engineering Ⅲ
    開講年度 : 2021
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 構造解析，物性評価，鉱物の利用，流体の分析，選別技術

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