Researcher basic information

• 学士, モラトゥワ大学、スリランカ
• PhD, Hokkaido University
• 博士, 北海道大学

• https://researchmap.jp/elakneswaran?lang=en

• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=201501007842473544
• http://www.eng.hokudai.ac.jp/labo/cher/index.html

• 201501007842473544

• Nuclear waste management
• Geopolymer
• CO2 Capture
• Surface chemistry
• multi species transport
• EOR
• durability
• Cement chemistry

• Energy Engineering, Earth resource engineering, Energy sciences
• Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention), Building structures and materials
• Environmental Science/Agriculture Science, Environmental load reduction and remediation

• Bachelor's degree program, School of Engineering
• Master's degree program, Graduate School of Engineering
• Doctoral (PhD) degree program, Graduate School of Engineering

Research activity information

• Dec. 2025, 16th International Conference on Sustainable Built Environment 2025 (ICSBE 2025) and Next-generation Innovation & Advancement – Diamond 75, Best Scientific Paper
• Feb. 2025, Materials and Structures Journal, Outstanding Paper 2024 Award
• Jun. 2019, 石油学会 2019 年度論文賞
• Mar. 2018, Best Presentation Award ICCCCT2018
• Aug. 2016, 論文賞 4th International Conference on Sustainable Construction Materials & Technologies
• Jun. 2013, 論文賞 RILEM 2013：Symposium on Multi-Scale Modeling and Characterization of Infrastructure Materials
• Jun. 2011, 博士論文賞 山田一宇賞（前田記念工学振興財団）
• Aug. 2003, First class honors モラトゥワ大学（スリランカ）

• Fresh and hardened properties of 3D printed concrete with cement kiln dust and CO ₂
  Kirushnapillai Kopitha; Akilesh Ramesh; Pathmanathan Rajeev; Jay Sanjayan; Yogarajah Elakneswaran
  Journal of Sustainable Cement-Based Materials, 1, 13, Informa UK Limited, 27 Apr. 2026
  Scientific journal
• Buildability Enhancement of 3D Printed Concrete Using Carbonated Water and Partial Replacement of OPC with Reactive MgO
  Kirushnapillai Kopitha; Pathmanathan Rajeev; Jay Sanjayan; Yogarajah Elakneswaran
  Journal of Advanced Concrete Technology, 24, 2, 60, 72, Japan Concrete Institute, 03 Feb. 2026
  Scientific journal
• Effect of different compositions of recycled concrete powder on the hydration characteristics of cement paste
  Binglin Guo; Kaixuan Wang; Cun Wang; Yuxing Gao; Di Lu; Huyong Qin; Yang Liu; Binggen Zhan; Qijun Yu; Yogarajah Elakneswaran
  Circular Economy, 100182, 100182, Elsevier BV, Feb. 2026
  Scientific journal
• Mechanistic Insights into the Interaction between Strätlingite and I ^– /IO ₃ ^– : Implications on the Iodine Migration in Alkali-Activated Slag Cement
  Binglin Guo; Cheng Wang; Ping Ye; Huyong Qin; Yuting Chu; Kaixuan Wang; Hengjun Mei; Peng Gao; Binggen Zhan; Qijun Yu; Keiko Sasaki; Yogarajah Elakneswaran
  Inorganic Chemistry, American Chemical Society (ACS), 01 Feb. 2026
  Scientific journal
• Tailoring neutron-shielding boron-metakaolin geopolymers with B4C filler: Surfactant-driven interfacial and microstructural control
  Xiaobo Niu; Yogarajah Elakneswaran; Ryosuke Kikuchi; Ang Li; Sivasubramaniam Seralathan; Yoshihisa Hiraki; Junya Sato; Takeshi Osugi; Takashi Kamiyama; Brant Walkley
  Cement and Concrete Research, 200, 108096, 108096, Elsevier BV, Feb. 2026
  Scientific journal
• Exploring the Limit of Low-Salinity Waterflooding in a Carbonate Reservoir With Low Total Acid Number Oil
  Takaaki Uetani; Miku Takeya; Elakneswaran Yogarajah
  SPE Journal, 1, 16, Society of Petroleum Engineers (SPE), 01 Jan. 2026
  Scientific journal, Summary
  
  This paper presents a workflow for designing the optimal injection brine composition for an offshore carbonate reservoir. The crude oil from this reservoir has a very low total acid number (TAN of 0.01 mg KOH/g), leading to the expectation that injecting diluted seawater (SW) would be an ineffective enhanced oil recovery (EOR) fluid. To address this, we designed a water composition that maximizes electrostatic repulsion (total disjoining pressure) at the oil/rock interface. This was achieved by combining two surface complexation models (oil/water and calcite/water interfaces) to estimate surface potential, calibrated to represent the reservoir conditions, with the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The total disjoining pressure was calculated for more than 30 different brine compositions, and the composition demonstrating the highest value was selected. The optimized injection brine, termed “repulsive” water, was then evaluated in the laboratory for its oil recovery performance. Both spontaneous imbibition tests and coreflooding tests showed limited success with the repulsive water (RW), resulting in additional oil recovery factors of only 1–2%. We believe that the poor oil recovery results from insufficient repulsion at the oil/rock interface. Greater repulsion would be necessary for further oil recovery; however, this was not attained within the scope of this study. Additionally, injecting diluted SW also failed to yield promising oil recovery results. Based on these findings, we conclude that low-salinity waterflooding (LSW) is not a viable EOR option for the studied carbonate reservoir with a very low TAN. To the best of our knowledge, this is the first study to propose a workflow for designing the optimal injection water composition for LSW EOR using an electrokinetic approach.
• From cement chemistry to pseudo-ductile mechanical behaviour of engineered cementitious composite: A multiphysical approach
  Yuguo Yu; Chamila Gunasekara; Yogarajah Elakneswaran; Dilan Robert; David W. Law; Sujeeva Setunge
  Computers & Structures, 319, 108005, 108005, Elsevier BV, Dec. 2025
  Scientific journal
• Role of Bicarbonate Speciation and Brine Chemistry in Chalk Formations for CO ₂ Storage Efficiency
  Amir Ubaidah Mohd Zuki; Yogarajah Elakneswaran; Angelo Kennedy Lino Limaluka; Prashant Jadhawar
  Energy & Fuels, 39, 44, 21397, 21411, American Chemical Society (ACS), 27 Oct. 2025
  Scientific journal
• Optimizing Aqueous Amine Blends for Enhanced Carbon Capture and Mineralization in Cement-Based Materials
  Harshani Iresha; Yogarajah Elakneswaran; Ryoma Kitagaki; Ryoma Saito; Keiichi Yano; Yuya Yoda; Masato Tsujino; Akira Nishida; Hisanori Senboku; Koji Fushimi; Masatoshi Sakairi
  Journal of Advanced Concrete Technology, 23, 10, 470, 485, Japan Concrete Institute, 18 Oct. 2025
  Scientific journal
• Enhanced mechanical properties of cement pastes with CO2-bubbled alkanolamines: A study on hydration, carbonation, and mineralization behavior
  Tan Pan; Zhijian Li; Dayoung Oh; Ryoma Kitagaki; Yogarajah Elakneswaran; Ryosuke Saito; Keiichi Yano; Yuya Yoda; Masato Tsujino; Akira Nishida; Hisanori Senboku; Koji Fushimi; Masatoshi Sakairi
  Journal of Environmental Chemical Engineering, 13, 5, 118658, 118658, Elsevier BV, Oct. 2025
  Scientific journal
• Enhanced stabilisation of simulant organic nuclear wastes in metakaolin-based geopolymers using graphene oxide
  Sivasubramaniam Seralathan; Xiaobo Niu; Yogarajah Elakneswaran; Chewei Fang
  Applied Clay Science, 271, 107793, 107793, Elsevier BV, Jul. 2025
  Scientific journal
• Correlating strength development with hydration characteristics for multi-blend fly ash concrete
  Yuguo Yu; Chamila Gunasekara; Yogarajah Elakneswaran; Dilan Robert; David W. Law; Sujeeva Setunge
  Journal of Building Engineering, 103, 112076, 112076, Elsevier BV, Jun. 2025
  Scientific journal
• Incorporation of boron into metakaolin-based geopolymers for radionuclide immobilisation and neutron capture potential
  Xiaobo Niu; Yogarajah Elakneswaran; Ang Li; Sivasubramaniam Seralathan; Ryosuke Kikuchi; Yoshihisa Hiraki; Junya Sato; Takeshi Osugi; Brant Walkley
  Cement and Concrete Research, 190, 107814, 107814, Elsevier BV, Apr. 2025
  Scientific journal
• CO2 sequestration and low carbon strategies in 3D printed concrete
  Kirushnapillai Kopitha; Pathmanathan Rajeev; Jay Sanjayan; Yogarajah Elakneswaran
  Journal of Building Engineering, 99, 111653, 111653, Elsevier BV, Apr. 2025
  Scientific journal
• Influence of amorphous content in recycled fly ash on binder hydration characteristics
  Yuguo Yu; Chamila Gunasekara; Yogarajah Elakneswaran; Dilan Robert; David W. Law; Sujeeva Setunge
  Journal of Material Cycles and Waste Management, Springer Science and Business Media LLC, 07 Jan. 2025
  Scientific journal, Abstract
  
  Greening of the construction sector has witnessed the widespread practice of recycling fly ash into building materials for decades. The control of ash waste quality is an important aspect for its viability as a supplementary cementitious material, where the detailed physical and chemical characteristics play crucial roles. To better facilitate informed greener design, a novel method is leveraged to study particularly the influence of amorphous content in fly ash on binder hydration. In this study, a coupled kinetic-thermodynamic approach is implemented to realise comprehensive hydration assessment. The adopted kinetics-based model is developed following unified theory to quantify the hydration/reaction degrees for cement and fly ash. Such kinetic information is further utilised in thermodynamic analysis, powered by Gibbs energy minimisation method, to evaluate the time-dependent phase assemblage of cementitious system upon continuous hydration. The applied technique is carefully verified against a series of reported tests, before further exploited to conduct numerical explorations. Computational findings highlight the influence of amorphous content in fly ash on the chemo-physical–mechanical properties of concrete products, providing insights for future sustainable construction material design.
• Alkaline ethanolamine as dual-functional agent: Effective CO2 capture agent and corrosion inhibitor for structural applications
  Govindaraj Yoganandan; Ryosuke Saito; Keiichi Yano; Masatoshi Sakairi; Koji Fushimi; Ryoma Kitagaki; Yogarajah Elakneswaran; Hisanori Senboku; Yuya Yoda; Masato Tsu-jino; Akira Nishida
  Chemical Engineering Journal, 504, 158810, 158810, Elsevier BV, Jan. 2025
  Scientific journal
• Immobilisation of iodide in alkali-activated materials
  Raudhatul Islam Chaerun; Manami Ishimura; Pramesti Prihutami; Xiaobo Niu; Yusuke Ohya; Kazuma Kuroda; Kanako Toda; Ryosuke Kikuchi; Tsubasa Otake; John L. Provis; Yogarajah Elakneswaran; Tsutomu Sato
  Chemosphere, 369, 143871, 143871, Elsevier BV, Dec. 2024
  Scientific journal
• Enhancing CO2 capture in cement-based materials with alkanolamines: A comprehensive study on efficiency, phase-specific impact, and carbonation mechanisms
  Kirushnapillai Kopitha; Yogarajah Elakneswaran; Ryoma Kitagaki; Ryosuke Saito; Keiichi Yano; Yuya Yoda; Masato Tsujino; Akira Nishida; Hisanori Senboku; Koji Fushimi; Masatoshi Sakairi
  Science of The Total Environment, 957, 177463, 177463, Elsevier BV, Dec. 2024
  Scientific journal
• On the hydration of limestone calcined kaolinitic clay cement and energy-efficient production
  Yuguo Yu; Chamila Gunasekara; Yogarajah Elakneswaran; Dilan Robert; David W. Law; Sujeeva Setunge
  Cement and Concrete Composites, 153, 105698, 105698, Elsevier BV, Oct. 2024
  Scientific journal
• Exploring the reinforcing mechanism of graphene oxide in cementitious materials through microstructural analysis of synthesised calcium silicate hydrate
  Mylvaganam Nithurshan; Yogarajah Elakneswaran; Yuya Yoda; Keiichi Yano; Ryoma Kitagaki; Naoki Hiroyoshi
  Cement and Concrete Composites, 153, 105717, 105717, Elsevier BV, Oct. 2024
  Scientific journal
• Influence of inorganic solid particles on the stability of water-in-crude oil emulsions: Evaluating the role of surface charge
  Tokima Hattori; Yogarajah Elakneswaran; Xingjuan Hao; Mai Shimokawara; Naoki Hiroyoshi
  Colloids and Surfaces A: Physicochemical and Engineering Aspects, 699, 134726, 134726, Elsevier BV, Oct. 2024
  Scientific journal
• Report of RILEM TC 281-CCC: A critical review of the standardised testing methods to determine carbonation resistance of concrete
  Susan A. Bernal; Yuvaraj Dhandapani; Yogarajah Elakneswaran; Gregor J. G. Gluth; Elke Gruyaert; Maria C. G. Juenger; Barbara Lothenbach; Kolawole A. Olonade; Marlene Sakoparnig; Zhenguo Shi; Charlotte Thiel; Phillip Van den Heede; Hanne Vanoutrive; Stefanie von Greve-Dierfeld; Nele De Belie; John L. Provis
  Materials and Structures, 57, 8, Springer Science and Business Media LLC, 03 Sep. 2024
  Scientific journal, Abstract
  
  The chemical reaction between CO₂ and a blended Portland cement concrete, referred to as carbonation, can lead to reduced performance, particularly when concrete is exposed to elevated levels of CO₂ (i.e., accelerated carbonation conditions). When slight changes in concrete mix designs or testing conditions are adopted, conflicting carbonation results are often reported. The RILEM TC 281-CCC ‘Carbonation of Concrete with Supplementary Cementitious Materials’ has conducted a critical analysis of the standardised testing methodologies that are currently applied to determine carbonation resistance of concrete in different regions. There are at least 17 different standards or recommendations being actively used for this purpose, with significant differences in sample curing, pre-conditioning, carbonation exposure conditions, and methods used for determination of carbonation depth after exposure. These differences strongly influence the carbonation depths recorded and the carbonation coefficient values calculated. Considering the importance of accurately determining carbonation potential of concrete, not just for predicting their durability performance, but also for determining the amount of CO₂ that concrete can re-absorb during or after its service life, it is imperative to recognise the applicability and limitations of the results obtained from different tests. This will enable researchers and practitioners to adopt the most appropriate testing methodologies to evaluate carbonation resistance, depending on the purpose of the conclusions derived from such testing (e. g. materials selection, service life prediction, CO₂ capture potential).
• Influence of Reservoir Salinity, Mineralogy, Temperature, and Pressure on Geochemical Hydrogen Loss in Depleted Carbonates
  Angelo Kennedy Lino Limaluka; Elakneswaran Yogarajah; Naoki Hiroyoshi; Moataz Abu-AlSaud; Dong Kyu Cha; Subhash C. Ayirala
  SPE Journal, 29, 10, 5690, 5701, Society of Petroleum Engineers (SPE), 29 Jul. 2024
  Scientific journal, Summary
  
  Underground hydrogen storage (UHS) is a cost-effective and safer system vital for the growth of the hydrogen market and its role as an essential transitional fuel. Presently, depleted hydrocarbon reservoirs (DHR) account for more than 75% of all UHS sites due to their higher prevalence and readiness for use. However, hydrogen (H2) loss primarily due to abiotic interactions poses a significant challenge to the integrity of DHR sites, and while the underlying conditions have been investigated in some studies, the conclusions have been inconsistent, particularly for carbonate reservoirs. In this study, we analyzed the impact of reservoir physical and chemical parameters, (i.e., salinity, mineralogy, temperature, and pressure) on H2-brine-mineral interactions and the extent of H2 loss in carbonate formations. Static batch simulations were performed using PHREEQC and MATLAB® for a 1-year storage cycle period with three different brine and rock samples at 50–130°C and 15–30 MPa. The results showed that the dissociation of H2 and formation of CH4 and H2S increased with increasing temperature, at a two times higher rate compared to pressure. Also, markedly, in various brine compositions and reactive mineralogy, a 20% or less H2 loss could be attained in temperatures <50°C and 115–130°C, with pressure below 17 MPa; meanwhile, the pressure condition 18 MPa and greater (at 50°C) would risk at least 50% loss, with >86% from 19 MPa. Second, H2 loss increased to 80% after about 50 days for all the brines, and pressure and temperature conditions in the mineral sample with the largest composition of reactive minerals (i.e., pyrite, anhydrite, etc.) suggested a 50% loss risk in such mineralogy during the storage cycle period of about 1 month. Lastly, in the mineral sample with >90 wt% calcite and 0–2 wt% reactive minerals composition, H2 molality increased at least fourfold on average across the storage period and reservoir brine/temperature/pressure conditions. This result further indicates that reactive mineralogy has a more significant effect on the stability of hydrogen relative to temperature and pressure in a carbonate UHS formation. In summary, the findings suggest that a minimal reactive mineral composition, 100°C or higher, and 17 MPa or lower constitutes a set of reservoir physical and chemical conditions with the potential for a limited risk of H2 loss (<20%) in carbonate DHR. However, the extension of the present work to the dynamic UHS conditions is necessary to further ascertain these conclusions.
• Surface chemistry and radionuclide anion immobilisation potential of phosphoric acid-activated metakaolin-based geopolymers
  Xiaobo Niu; Yogarajah Elakneswaran; Naoki Hiroyoshi
  Cement and Concrete Research, 181, 107549, 107549, Elsevier BV, Jul. 2024
  Scientific journal
• Unified hydration model for multi-blend fly ash cementitious systems of wide-range replacement rates
  Yuguo Yu; Chamila Gunasekara; Yogarajah Elakneswaran; Dilan Robert; David W. Law; Sujeeva Setunge
  Cement and Concrete Research, 180, 107487, 107487, Elsevier BV, Jun. 2024
  Scientific journal
• Role of Semiconductive Property on Selective Cementation Mechanism of Iron Oxides to Gold in Galvanic Interaction with Zero-Valent Aluminum from Gold–Copper Ammoniacal Thiosulfate Solutions
  Joshua Zoleta; Kosei Aikawa; Nako Okada; Ilhwan Park; Mayumi Ito; Yogarajah Elakneswaran; Naoki Hiroyoshi
  Metals, 14, 5, 550, 550, MDPI AG, 07 May 2024
  Scientific journal, Iron oxides (hematite, Fe2O3, and magnetite, Fe3O4), previously used as electron mediators in the galvanic system with zero-valent aluminum (ZVAl), have been shown to recover Au upon cementation in Au–Cu ammoniacal thiosulfate media selectively, and this warrants further investigation. This research is focused on investigating the role of the semiconductive properties of metal oxides by performing a cementation experiment by mixing 0.15 g of electron mediators (Fe3O4, Fe2O3, TiO2 (anatase and rutile)) and 0.15 g of zero-valent aluminum powder as an electron donor in various electrochemical experiments. The results revealed that upon the cementation experiment, synthetic Fe2O3 and Fe3O4 were consistently able to selectively recover Au at around 90% and Cu at around 20%. Compared to activated carbon (AC), TiO2, in anatase and rutile forms, obtained selective recovery of gold, but the recovery was utterly insignificant compared to that of iron oxides, obtaining an average of 93% Au and 63% Cu recovery. The electrochemical and surface analysis supports the results obtained upon the cementation process, where TiO2, upon cyclic voltammetry (CV), obtained two reduction peaks centered at −1.0 V and −0.5 V assigned to reducing Au and Cu ions, respectively. Furthermore, various electrochemical impedance spectroscopic analyses revealed that the flat band potential obtained in the Mott–Schottky plot is around −1.0 V and −0.2 V for iron oxides and titanium oxides, respectively, suggesting that the electrons travel from semiconductor interface to electrolyte interface, and electrons are accessible only to Au ions in the electrolyte interface (reduction band edge around −1.0 V). The determination of this selective cementation mechanism is one of a kind. It has been proposed that the semiconductive properties of Fe2O3, Fe3O4, and, by configuring their relative energy band diagram, the travel of electrons from the iron oxide–electrolyte interface facilitate the selective cementation towards Au(S2O3)23+ ions in gold–copper ammoniacal thiosulfate solutions.
• Macroscale Modeling of Geochemistry Influence on Polymer and Low-Salinity Waterflooding in Carbonate Oil Reservoirs
  Angelo Kennedy Lino Limaluka; Yogarajah Elakneswaran; Naoki Hiroyoshi
  ACS Omega, American Chemical Society (ACS), 05 Apr. 2024
  Scientific journal
• Multiscale computational modelling of nano-silica reinforced cement paste: Bridging microstructure and mechanical performance
  Mylvaganam Nithurshan; Yogarajah Elakneswaran; Yuya Yoda; Ryoma Kitagaki; Naoki Hiroyoshi
  Construction and Building Materials, 425, 136047, 136047, Elsevier BV, Apr. 2024
  Scientific journal
• Development and verification of an integrated hydration, geochemical and transport model for the hydrated cement paste exposed to an aggressive chemical environment
  Siventhirarajah Krishnya; Kirushnapillai Kopitha; Yuya Yoda; Ryoma Kitagaki; Yogarajah Elakneswaran
  Cement and Concrete Composites, 146, Feb. 2024
  Scientific journal
• Effect of Superabsorbent Polymer (SAP) Size on Microstructure and Compressive Strength of Concrete
  Xiaobo Niu; Yile Zhang; Yogarajah Elakneswaran; Miyu Sasaki; Takeshi Takayama; Hajime Kawai
  Polymers, 16, 2, 197, 197, MDPI AG, 09 Jan. 2024
  Scientific journal, Superabsorbent polymers (SAPs) are hydrophilic, polymeric network materials renowned for their ability to enhance various properties of cementitious materials. This investigation examines the impact of SAP size on the hydration degree, porosity, and compressive strength of cement pastes and concrete under diverse curing conditions and ageing periods. The findings reveal that SAP addition stimulates the hydration of the C2S phase, particularly during the early curing stages, thereby favouring early strength development. However, the effect of SAPs on hydration promotion diminishes as their size increases. Conversely, the size of SAPs affects the hydration range of their action, and the 400 µm SAP demonstrates the most extensive range of hydration enhancement, reaching up to 105 µm. Additionally, SAPs effectively reduce porosity in small pores (4 nm–10 μm), with 200 μm and 400 μm SAPs exhibiting the highest efficacy. While analysing the effects of SAPs on larger pores (>10 μm), the results show that although larger SAPs result in larger average porosity, the total porosity is effectively reduced, particularly in samples incorporating 400 μm SAP. The compressive strength of cement paste, even after 28 days, is slightly reduced following the introduction of SAPs. However, the strength of concrete, due to the naturally occurring pores eliminating the negative effects of the pores produced by SAPs, is significantly increased following the introduction of SAPs, especially 400 µm SAP.
• Development of metakaolin-based geopolymer for selenium oxyanions uptake through in-situ ettringite formation
  Xiaobo Niu; Yogarajah Elakneswaran; Raudhatul Islam Chaerun; Chuwei Fang; Naoki Hiroyoshi; John L. Provis; Tsutomu Sato
  Separation and Purification Technology, 324, 124530, 124530, Elsevier BV, Nov. 2023
  Scientific journal
• N-methyldiethanolamine (MDEA) as an effective CO2 absorbent for direct air capture (DAC) in cement-based materials
  Kirushnapillai Kopitha; Yogarajah Elakneswaran; Ryoma Kitagaki; Ryosuke Saito; Masato Tsujino; Akira Nishida; Hisanori Senboku; Naoki Hiroyoshi
  Chemical Engineering Journal, 475, 146067, 146067, Elsevier BV, Nov. 2023
  Scientific journal
• Fluid-fluid interfacial properties during low salinity waterflooding
  Yongqiang Chen; Javad Shokri; Vahid Niasar; Mohamed Mehana; Colin D. Wood; Yogarajah Elakneswaran; Juju Zhao
  Journal of Molecular Liquids, 390, 123142, 123142, Elsevier BV, Nov. 2023
  Scientific journal
• Proposing a Finite Element-based Multi-stage Model to Predict the Mechanical Properties of Cement Paste
  NanoWorld Journal, 9, United Scientific Group, 22 Sep. 2023
  Scientific journal
• Role of pH and cations on emulsion formation and stability of crude oils
  Xingjuan Hao; Yogarajah Elakneswaran; Sadia Afrin; Mai Shimokawara; Yoshitake Kato; Ryuta Kitamura; Naoki Hiroyoshi
  Geoenergy Science and Engineering, 227, 211905, 211905, Elsevier BV, Aug. 2023
  Scientific journal
• A Pretreatment of Refractory Gold Ores Containing Sulfide Minerals to Improve Gold Leaching by Ammonium Thiosulfate: A Model Experiment Using Gold Powder and Arsenic-Bearing Sulfide Minerals
  Takunda Joseph Mhandu; Ilhwan Park; Sanghee Jeon; Sohta Hamatsu; Yogarajah Elakneswaran; Mayumi Ito; Naoki Hiroyoshi
  Metals, 13, 8, 1357, 1357, MDPI AG, 28 Jul. 2023
  Scientific journal, The use of thiosulfate to extract gold from refractory ores is promising because of its non-toxicity and high selectivity. Sulfide minerals (i.e., pyrite, arsenopyrite, chalcopyrite), major gold carriers in refractory gold ores, however, hinder gold extraction due to the high consumption of a lixiviant. In this study, a new method to improve gold extraction from sulfide bearing gold ores is proposed based on the model experiments using a mixture of gold powder and arsenopyrite-bearing sulfide (HAsBS) ore. The effects of HAsBS ore on gold leaching in ammonium thiosulfate solutions were investigated, and it was found that gold extraction in the presence of HAsBS ore was suppressed because of the unwanted decomposition of thiosulfate on the surface of sulfide minerals. To improve gold extraction in the presence of the sulfide minerals, this study investigated the effects of the pretreatment of HAsBS ore using ammonium solutions containing cupric ions and confirmed that HAsBS ore was oxidized in the pretreatment and its surface was covered by the oxidation products. As a result, thiosulfate consumption was minimized in the subsequent gold leaching step using ammonium thiosulfate, resulting in an improvement in gold extraction from 10% to 79%.
• Selective Cementation of Gold Using an Iron Oxide and Zero-Valent Aluminum Galvanic System from Gold–Copper Ammoniacal Thiosulfate Solutions
  Joshua Zoleta; Sanghee Jeon; Akuru Kuze; Nako Okada; Ilhwan Park; Mayumi Ito; Yogarajah Elakneswaran; Naoki Hiroyoshi
  Metals, 13, 7, 1289, 1289, MDPI AG, 18 Jul. 2023
  Scientific journal, Ammonium thiosulfate leaching is a promising alternative to the conventional cyanide method for extracting gold from ores. However, strategies for recovering gold from the leachate are less commercially used due to its low affinity to gold. The present study investigated the recovery of gold from the leachate using iron oxides (hematite, Fe2O3 or magnetite, Fe3O4). Cementation experiments were conducted by mixing 0.15 g of aluminum powder as an electron donor and 0.15 g of an electron mediator (activated carbon, hematite, or magnetite) in 10 mL of ammonium thiosulfate leachate containing 100 mg/L gold ions and 10 mM cupric ions for 24 h at 25 °C. The results of the solution analysis showed that when activated carbon (AC) was used, the gold was recovered together with copper (recoveries were 99.99% for gold and copper). However, selective gold recovery was observed when iron oxides were used, where the gold and copper recoveries were 89.7% and 21% for hematite and 85.9% and 15.4% for magnetite, respectively. An electrochemical experiment was also conducted to determine the galvanic interaction between the electron donor and electron mediator in a conventional electrochemical setup (hematite/magnetite–Al as the working electrode, Pt as the counter electrode, Ag/AgCl as the reference electrode) in a gold–thiosulfate medium. Cyclic voltammetry showed a gold reduction “shoulder-like” peak at −1.0 V using hematite/Al and magnetite/Al electrodes. Chronoamperometry was conducted and operated at a constant voltage (−1.0 V) determined during cyclic voltammetry and further analyzed using SEM-EDX. The results of the SEM-EDX analysis for the cementation products and electrochemical experiments confirmed that the gold was selectively deposited on the iron oxide surface as an electron mediator.
• Zonal Isolation Material for Low-Temperature Shallow-Depth Application: Evaluation of Early Properties Development
  Madhan Nur Agista; Mahmoud Khalifeh; Arild Saasen; Elakneswaran Yogarajah
  SPE Journal, 1, 13, Society of Petroleum Engineers (SPE), 01 Jul. 2023
  Scientific journal, Summary
  
  Shallow-depth cementing presents unique challenges due to its low temperature and low pore pressure characteristic. The curing process of the cementitious material is typically prolonged at low temperatures resulting in a delayed curing process. The use of a low-density slurry to mitigate low pore pressure introduces another challenge, as it leads to a reduction in the final compressive strength. On the other hand, the operation requires the material to develop enough strength swiftly to be able to efficiently continue the next drilling operation. In addition, the presence of flow zones such as shallow gas and shallow water flow increases the complexity of the cementing process. There have been many developments in cementitious materials for shallow-depth cementing such as rapid-hardening cement and gas tight cement. However, there is little research focusing on the performance evaluation of each material at low-temperature conditions. This paper aims to present a thorough material evaluation for low-temperature shallow-depth cementing. The incorporated materials are American Petroleum Institute (API) Class G cement, rapid-hardening cement, gas tight cement, and geopolymer. Geopolymer is included to evaluate its potential as the green alternative to Portland-based cement. The sets of characterization were conducted during the liquid, gel, and solid phases. The samples were prepared under wide-ranging low temperatures and typical bottomhole pressures for shallow sections. The result shows different performances of each material and its behavior under low temperatures such as prolonged strength development and low reactivity, which necessitates further development of these materials.
• A systematic review and assessment of concrete strength prediction models
  Mylvaganam Nithurshan; Yogarajah Elakneswaran
  Case Studies in Construction Materials, 18, e01830, e01830, Elsevier BV, Jul. 2023
  Scientific journal
• Network Degradation Assessed by Evolved Gas Analysis–Mass Spectrometry Combined with Principal Component Analysis (EGA–MS–PCA): A Case of Thermo-Oxidized Epoxy/Amine Network
  Takato Ishida; Ryoma Kitagaki; Yogarajah Elakneswaran; Junji Mizukado; Hideyuki Shinzawa; Hiroaki Sato; Hideaki Hagihara; Ryota Watanabe
  Macromolecules, 56, 3, 883, 891, 18 Jan. 2023
  English, Scientific journal
• Promoting CO₂ Fixation in Existing Concrete Structure Using Amine
  Saito R.; Elakneswaran Y.; Tsujino M.; Kitagaki R.
  Concrete Journal, 61, 9, 854, 858, Japan Concrete Institute, 2023
  Japanese
• Numerical Simulation of Chloride Ion Ingression in Mortar Incorporating the Effect of ITZ Using an Integrated COMSOL-IPHREEQC Framework
  Siventhirarajah Krishnya; Yogarajah Elakneswaran; Yuya Yoda; Ryoma Kitagaki
  RILEM Bookseries, 43, 686, 696, 2023
  In book
• Effect of Carbonation on Microstructure of Cement Pastes with Different Water-to-Cement Ratios
  K. Kopitha; S. Krishnya; Y. Elakneswaran; R. Kitagaki; Y. Yoda; M. Tsujino; A. Nishida
  Lecture Notes in Civil Engineering, 362 LNCE, 149, 159, 2023
  International conference proceedings
• Investigating the hydration characteristics of a new composite cementitious binder containing of slag and calcite
  Chuang Li; Siventhirarajah Krishnya; Masataka Ogino; Eiji Owaki; Yogarajah Elakneswaran
  Construction and Building Materials, 361, 129629, 129629, Elsevier BV, Dec. 2022
  Scientific journal
• Coupling of a Reservoir Simulator with Geochemistry for Chemical Enhanced Oil Recovery
  Angelo Kennedy Lino Limaluka; Yogarajah Elakneswaran
  Day 4 Thu, November 03, 2022, SPE, 31 Oct. 2022
  International conference proceedings, Abstract
  
  Chemical enhanced oil recovery (CEOR) techniques are some of the most effective and economical tertiary oil extraction processes. As a key tool for the recovery performance evaluation, reservoir simulation plays an instrumental role in the expansion of the field application of CEOR. However, their framework models essentially the physical aspect of the recovery process. The significant influence of geochemical interactions on the recovery performance remains largely unintegrated. In this study, MATLAB Reservoir Simulation Toolbox (MRST) was coupled with PHREEQC for improved modeling and simulation of polymer flooding and low salinity water flooding (LSWF). The MRST’s polymer model was extended for multi-phase chemical transport by the addition of chemical species in wells boundary conditions, and phase relative permeabilities were modified to account for the wettability alteration effect of the flooding process. In validation, the coupled model showed a good match against PHREEQC in a simulation of a single-phase carbonate core low salinity water flooding (LSWF). It also validated well in the case of matching high salinity experimental results. A demonstrative application of the coupled model in the simulation of LSWF showed 27% maximum incremental oil recovery with a 3.3 mean water-oil ratio (WOR). Furthermore, combining LSWF with polymer flooding achieved the same recovery potential but with much lower water production (0.2 WOR) and doubled production period. These results preliminarily indicate that polymer flooding and LSWF could be combined for at least 27% additional original oil in place (OOIP) recovery with no more than 1 WOR in carbonate reservoirs. However, as this recovery performance evaluation was done in 1D, further work on the coupled model includes improving it for multi-dimensional application.
• Retention mechanism of cesium in chabazite embedded into metakaolin-based alkali activated materials
  Raudhatul Islam Chaerun; Natatsawas Soonthornwiphat; Kanako Toda; Kazuma Kuroda; Xiaobo Niu; Ryosuke Kikuchi; Tsubasa Otake; Yogarajah Elakneswaran; John L. Provis; Tsutomu Sato
  Journal of Hazardous Materials, 440, 129732, 129732, Elsevier BV, Oct. 2022
  Scientific journal
• In-situ infrared cure monitoring combined with two-trace two-dimensional (2T2D) correlation analysis to elucidate the matrix–filler interaction of nanocomposites: Case of thermosetting urethane/silica nanospheres
  Takato Ishida; Ryota Watanabe; Hideyuki Shinzawa; Junji Mizukado; Hideaki Hagihara; Ryoma Kitagaki; Yogarajah Elakneswaran
  Polymer Testing, 112, 107587, 107587, Aug. 2022
  English, Scientific journal
• Adsorption behaviour of simulant radionuclide cations and anions in metakaolin-based geopolymer
  Xiaobo Niu; Yogarajah Elakneswaran; Chaerun Raudhatul Islam; John L. Provis; Tsutomu Sato
  Journal of Hazardous Materials, 429, 128373, 128373, Elsevier BV, May 2022
  Scientific journal
• Evaluating the Effect of Carbonate Impurities on Wettability Alteration Using a Geochemical Model
  Xingjuan Hao; Moataz Abu-Al-Saud; Subhash Ayirala; Yogarajah Elakneswaran
  Day 3 Wed, April 27, 2022, SPE, 18 Apr. 2022
  International conference proceedings, Abstract
  
  Wettability alteration considered as the principal mechanism has attracted more attention for low salinity waterflooding effect. It was significantly affected by electrokinetic interactions, which occurred at the interfaces of rock/brine and crude oil/brine. The mineral impurities of natural carbonate releasing ions have an important impact on the electrokinetics, which could lead to wettability shift subsequently. In this study, the effect of dolomite and anhydrite as the main impurities in natural carbonate, which caused wettability alteration, was evaluated using triple-layer surface complexation and thermodynamic equilibrium models coupled with extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The electrokinetics of crude oil and carbonate in brines were predicted by the triple-layer surface complexation model (TLM) based on zeta potential, while thermodynamic equilibrium model was mainly used for analyzing the carbonate impurities on wettability alteration. The equilibrium constants of reactions were determined by successfully fitting the calculated zeta potentials with measured ones for crude oil and carbonate in different solutions, which were validated for zeta potential prediction in smartwater. The disjoining pressure results show that there is a repulsion between crude oil and carbonate in Na2SO4 brine (Brine3) or smartwater (Brine4) equilibrating with calcite when comparing to that in MgCl2 (Brine1) and CaCl2 (Brine2), indicating the water-wet condition caused by the presence of sulphate ions. Moreover, the equilibrium of carbonate impurities with smartwater increases the repulsion between oil and carbonate. When the sulphate ion concentration in the adjusted smartwater exceeds a certain value, the effect of carbonate impurities on wettability alteration is not significant. Finally, the influence of smartwater pH on the interaction between oil and carbonate was evaluated with or without considering the equilibrium of carbonate impurities.
• Modelling the Impact of Surface Charge on Wettability Alteration in Low Salinity Waterflooding
  Yogarajah Elakneswaran
  Day 2 Tue, April 26, 2022, SPE, 18 Apr. 2022
  International conference proceedings, Abstract
  
  The wettability alteration is the most prominent mechanism for a favorable effect of low salinity water flooding in enhanced oil recovery. It has been accepted that the surface charge at crude oil/brine and rock/brine interfaces significantly influences the interaction of the crude oil with rock surface and thus wettability changes. In this study, the interface characteristics were coupled with a solute transport model to simulate low salinity waterflooding in carbonate and sandstone reservoirs. The ionic transport and two- phase flow of oil and water equations were solved and coupled with IPhreeqc for geochemical calculations. The dissolution and precipitation of minerals were considered thorough thermodynamic equilibrium reactions in IPhreeqc. In addition, a triple layer surface complexation model was employed in IPhreeqc to predict electrokinetic properties of crude oil/brine and rock/brine interfaces. The wettability alteration was calculated based the adsorbed polar components of crude oil on minerals’ surface, which changes the relative permeability. The coupled model able to predict the spatiotemporal variation of ionic profiles, surface and zeta potentials, dissolution and precipitation of minerals, total disjoining pressure, and wettability index in addition to oil recovery for the injection of brines. The validity of the coupled model results was tested against PHREEQC in a single-phase flow without the presence of oil. Moreover, the modelling results were compared with the published experimental data for a single-phase flow in carbonate cores. A very good agreement between experimental data and modelling results was obtained. Furthermore, the coupled model was applied to predict ionic concentration, pH profile, and oil recovery in both carbonate and sandstone cores and verified with experimental data. The modelling results reproduce well the experimental data, suggesting that model captures the geochemical and interface reactions. Finally, the coupled model can be used to optimize brine composition for improved oil recovery in carbonate and sandstone reservoirs.
• Delayed Absorption Superabsorbent Polymer for Strength Development in Concrete
  Yuka Morinaga; Yuya Akao; Daisuke Fukuda; Yogarajah Elakneswaran
  Materials, 15, 8, 2727, 2727, MDPI AG, 07 Apr. 2022
  Scientific journal
• Thermal aging of acrylic-urethane network: Kinetic modeling and end-of-life criteria combined with mechanical properties
  Takato Ishida; Emmanuel Richaud; Matthieu Gervais; Alain Gaudy; Ryoma Kitagaki; Hideaki Hagihara; Yogarajah Elakneswaran
  Progress in Organic Coatings, 163, 106654, 106654, Feb. 2022
  English, Scientific journal
• Modeling of hydration products and strength development for high-volume fly ash binders
  Siventhirarajah Krishnya; Charith Herath; Yogarajah Elakneswaran; Chamila Gunasekara; David W. Law; Sujeeva Setunge
  Construction and Building Materials, 320, 126228, 126228, Elsevier BV, Feb. 2022
  Scientific journal
• Proposing a three-phase model for predicting the mechanical properties of mortar and concrete
  Siventhirarajah Krishnya; Yogarajah Elakneswaran; Yuya Yoda
  Materials Today Communications, 29, 102858, 102858, Elsevier BV, Dec. 2021
  Scientific journal
• Influence of carbonate impurities on smartwater effect: Evaluation of wettability alteration process by geochemical simulation
  Xingjuan Hao; Moataz Abu-Al-Saud; Subhash Ayirala; Yogarajah Elakneswaran
  JOURNAL OF MOLECULAR LIQUIDS, 340, Oct. 2021
  English, Scientific journal
• Electrostatic properties of C–S–H and C-A-S-H for predicting calcium and chloride adsorption
  Satoshi Yoshida; Yogarajah Elakneswaran; Toyoharu Nawa
  Cement and Concrete Composites, 121, 104109, 104109, Aug. 2021
  English, Scientific journal
• Hydration of ferrite-rich Portland cement: Evaluation of Fe-hydrates and Fe uptake in calcium-silicate-hydrates
  Natsumi Noguchi; Krishnya Siventhirarajah; Takashi Chabayashi; Hiroyoshi Kato; Toyoharu Nawa; Yogarajah Elakneswaran
  CONSTRUCTION AND BUILDING MATERIALS, 288, Jun. 2021
  English, Scientific journal
• Role of moisture in photo-ageing -macromolecular architecture evolution of acrylic-urethane network
  Takato Ishida; Ryoma Kitagaki; Hideaki Hagihara; Yogarajah Elakneswaran
  Polymer Testing, 96, 107123, 107123, Apr. 2021
  English, Scientific journal
• Effect of Electrokinetics and Thermodynamic Equilibrium on Low-Salinity Water Flooding for Enhanced Oil Recovery in Sandstone Reservoirs
  Yogarajah Elakneswaran; Amir Ubaidah; Miku Takeya; Mai Shimokawara; Hirofumi Okano
  ACS OMEGA, 6, 5, 3727, 3735, Feb. 2021
  English, Scientific journal
• Durability of Slag-Blended Cementitious Materials Interacts with High Concentration of Sodium Sulphate
  Yogarajah Elakneswaran; Chuang Li; Tomohiro Kajio; Eiji Owaki; Masataka Ogino; Toyoharu Nawa
  RILEM Bookseries, 32, 39, 48, Springer Science and Business Media B.V., 2021
  English, In book
• A two-stage model for the prediction of mechanical properties of cement paste
  Siventhirarajah Krishnya; Yuya Yoda; Yogarajah Elakneswaran
  CEMENT & CONCRETE COMPOSITES, 115, Jan. 2021
  English, Scientific journal
• Durability of slag-blended cement due to U-phase instability in sulphate environment
  Yogarajah Elakneswaran; Chuang Li; Tomohiro Kajio; Eiji Owaki; Masataka Ogino; Toyoharu Nawa
  MATERIALS AND STRUCTURES, 53, 6, Dec. 2020
  English, Scientific journal
• Detecting pH and Ca2+ increase during low salinity waterflooding in carbonate reservoirs: Implications for wettability alteration process
  Yongqiang Chen; Amir Ubaidah; Yogarajah Elakneswaran; Vahid J. Niasar; Quan Xie
  Journal of Molecular Liquids, 317, 114003, 114003, Elsevier BV, Nov. 2020
  Scientific journal
• Intrinsic Differences on the Photodegradation Mechanisms between Pigmented and Non-Pigmented Coatings Determined by Multi-Scale Analysis
  T. Ishida; R. Kitagaki; H. Hagihara; Y. Elakneswaran
  XV International Conference on Durability of Building Materials and Components. eBook of Proceedings, CIMNE, Oct. 2020, [Peer-reviewed]
  English, International conference proceedings
• Encapsulation of Sr-loaded titanate spent adsorbents in potassium aluminosilicate geopolymer
  Natatsawas Soonthornwiphat; Yutaro Kobayashi; Kanako Toda; Kazuma Kuroda; Chaerun Raudhatul Islam; Tsubasa Otake; Yogarajah Elakneswaran; John L. Provis; Tsutomu Sato
  JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 57, 10, 1181, 1188, Oct. 2020
  English, Scientific journal
• A study of molecular architectural dynamics of crosslinked urethane during photo-aging by two-dimensional infrared correlation spectroscopy
  Takato Ishida; Ryoma Kitagaki; Ryota Watanabe; Hideaki Hagihara; Yogarajah Elakneswaran; Hideyuki Shinzawa
  POLYMER DEGRADATION AND STABILITY, 179, 109242, 109242, Sep. 2020
  English, Scientific journal
• Effects of a New Type of Shrinkage-Reducing Agent on Concrete Properties
  Mari Masanaga; Tsuyoshi Hirata; Hirokatsu Kawakami; Yuka Morinaga; Toyoharu Nawa; Yogarajah Elakneswaran
  MATERIALS, 13, 13, 3018, 3018, Jul. 2020
  English, Scientific journal
• Crude oil/brine/rock interface in low salinity waterflooding: Experiments, triple-layer surface complexation model, and DLVO theory
  Miku Takeya; Amir Ubaidah; Mai Shimokawara; Hirofumi Okano; Toyoharu Nawa; Yogarajah Elakneswaran
  JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING, 188, 106913, 106913, May 2020
  English, Scientific journal
• Integrated geochemical modelling of low salinity waterflooding for enhanced oil recovery in carbonate reservoir
  Yogarajah Elakneswaran; Miku Takeya; Amir Ubaidah; Mai Shimokawara; Hirofumi Okano; Toyoharu Nawa
  International Petroleum Technology Conference 2020, IPTC 2020, International Petroleum Technology Conference (IPTC), 2020
  English, International conference proceedings
• Adsorption / desorption phenomenon of crude oil to rock surface in low salinity waterflooding
  Mai Shimokawara; Miku Takeya; Chiaki Otomo; Yasuyuki Mino; Elakneswaran Yogarajah; Toyoharu Nawa
  International Petroleum Technology Conference 2020, IPTC 2020, International Petroleum Technology Conference (IPTC), 2020
  English, International conference proceedings
• Challenges in prediction of significant structural changes during photochemical "degelation" of acrylic-urethane network
  Takato Ishida; Ryoma Kitagaki; Hideaki Hagihara; Yogarajah Elakneswaran
  POLYMER, 186, 122035, 122035, Jan. 2020
  English, Scientific journal
• Effect of Acid Number on the Electrokinetic Properties of Crude Oil during Low-Salinity Waterflooding
  Miku Takeya; Mai Shimokawara; Yogarajah Elakneswaran; Hirofumi Okano; Toyoharu Nawa
  ENERGY & FUELS, 33, 5, 4211, 4218, May 2019, [Peer-reviewed]
  English, Scientific journal
• Characteristics of Ferrite-Rich Portland Cement: Comparison With Ordinary Portland Cement
  Yogarajah Elakneswaran; Natsumi Noguchi; Kazuki Matumoto; Yuka Morinaga; Takashi Chabayashi; Hiroyoshi Kato; Toyoharu Nawa
  FRONTIERS IN MATERIALS, 6, 97, May 2019, [Peer-reviewed]
  English, Scientific journal
• The effect of seeding of synthesized C-S-H with different C/S on early hydration reaction of alite
  Yumetoki Abe; Yuka Morinaga; Toyoharu Nawa; Yogarajah Elakneswaran
  Sustainable Construction Materials and Technologies, 2, International Committee of the SCMT conferences, 2019
  English, International conference proceedings
• Influence of Carbonated Water-rock Interactions on Enhanced Oil Recovery in Carbonate Reservoirs: Experimental Investigation and Geochemical Modeling
  Mai Shimokawara; Elakneswaran Yogarajah; Toyoharu Nawa; Satoru Takahashi
  JOURNAL OF THE JAPAN PETROLEUM INSTITUTE, 62, 1, 19, 27, 2019, [Peer-reviewed]
  English, Scientific journal
• Predicting the electrokinetic properties of the crude oil/brine interface for enhanced oil recovery in low salinity water flooding
  Miku Takeya; Mai Shimokawara; Yogarajah Elakneswaran; Toyoharu Nawa; Satoru Takahashi
  FUEL, 235, 822, 831, Jan. 2019, [Peer-reviewed]
  English, Scientific journal
• Modelling Long-Term Durability Performance of Cementitious Materials under Sodium Sulphate Interaction
  Yogarajah Elakneswaran; Eiji Owaki; Toyoharu Nawa
  APPLIED SCIENCES-BASEL, 8, 12, 2597, Dec. 2018, [Peer-reviewed]
  English, Scientific journal
• Influence of portlandite on Pyrex glass dissolution and the formation of alkali-silica chemical reaction products
  Natsumi Noguchi; Yuka Morinaga; Tomohiro Kajio; Elakneswaran Yogarajah; Toyoharu Nawa
  JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 101, 10, 4549, 4559, Oct. 2018, [Peer-reviewed]
  English, Scientific journal
• Influence of Surface Electrical Properties of C-S-H on Chloride Binding in Slag-Blended Cementitious Materials
  Elakneswaran Yogarajah; Toyoharu Nawa; Kiyofumi Kurumisawa
  JOURNAL OF MATERIALS IN CIVIL ENGINEERING, 30, 5, 1, May 2018, [Peer-reviewed]
  English, Scientific journal
• Impact of portlandite on alkali-silica reaction of pyrex glass and blastfurnace slag aggregate
  N. Noguchi; T. Kajio; Y. Morinaga; Y. Elakneswaran; T. Nawa; T. Ayan
  6th International Conference on Durability of Concrete Structures, ICDCS 2018, 267, 272, 2018
  International conference proceedings
• The Impact of Tortuosity on Chloride Ion Diffusion in Slag-Blended Cementitious Materials
  Akira Hatanaka; Yogarajah Elakneswaran; Kiyofumi Kurumisawa; Toyoharu Nawa
  JOURNAL OF ADVANCED CONCRETE TECHNOLOGY, 15, 8, 426, 439, Aug. 2017
  English, Scientific journal
• Carbon dioxide saturated water injection for EOR in carbonate reservoir
  Mai Shimokawara; Elakneswaran Yogarajah; Toyoharu Nawa; Satoru Takahashi
  Society of Petroleum Engineers - SPE Abu Dhabi International Petroleum Exhibition and Conference 2017, 2017-, Society of Petroleum Engineers, 2017
  English, International conference proceedings
• THE ROLE OF PORTLANDITE ON THE HYDRATION OF C₃A
  Tomohiro KAJIO; Yuka MORINAGA; Yogarajah ELAKNESWARAN; Toyoharu NAWA
  Cement Science and Concrete Technology, 71, 1, 40, 47, Japan Cement Association, 2017
  Scientific journal
• Hydration study of slag-blended cement based on thermodynamic considerations
  Yogarajah Elakneswaran; Eiji Owaki; Shigeyoshi Miyahara; Masataka Ogino; Tsuyoshi Maruya; Toyoharu Nawa
  CONSTRUCTION AND BUILDING MATERIALS, 124, 615, 625, Oct. 2016, [Peer-reviewed]
  English, Scientific journal
• Chemical degradation of cementitious materials in various sulfate environments: Experimental results and model prediction
  Y. Elakneswaran; T. Ishida
  Life-Cycle of Structural Systems: Design, Assessment, Maintenance and Management - Proceedings of the 4th International Symposium on Life-Cycle Civil Engineering, IALCCE 2014, 1655, 1662, 2015
  International conference proceedings
• Development and Verification of an Integrated Physicochemical and Geochemical Modelling Framework for Performance Assessment of Cement-Based Materials
  Yogarajah Elakneswaran; Tetsuya Ishida
  JOURNAL OF ADVANCED CONCRETE TECHNOLOGY, 12, 4, 111, 126, Apr. 2014
  English, Scientific journal
• Durability of cementitious materials under combined sulphate attack and leaching: Development and application of a coupled physicochemical and geochemical model
  Yogarajah Elakneswaran; Tetsuya Ishida
  Sustainable Construction Materials and Technologies, 2013-August, 2013
  International conference proceedings
• Multi-ion transport model in cement materials considering surface charge of hydrates
  T. Nawa; T. Goda; Y. Elakneswaran
  Proceedings of the 3rd International Conference on the Durability of Concrete Structures, ICDCS 2012, Hokkaido University Press, 2012
  English, International conference proceedings
• ESTIMATION OF SILANOL SITE DENSITY OF SYNTHESIZED C-S-H
  IWASA Akihito; GODA Tadashi; NAWA Toyoharu; ELAKNESWARAN Yogarajah
  Cement Science and Concrete Technology, 65, 1, 54, 60, Japan Cement Association, 2011
  Japanese, Chloride induced steel corrosion is the greatest durability problem in the reinforced concrete structures exposed to marine environment. Therefore, it is important to elucidate the mechanism of chloride transport into cementitious materials. Both ion-ion and ion-solid interactions are influencing on the chloride transport into cementitious materials. Chloride can interact with cement hydrates chemically as well as physically. The electrostatic interaction of chloride on the surface of calcium silicate hydrate（C-S-H）, the main hydration product of cementitious materials, can be considered as the physical adsorption. It has been proved that the physical adsorption of chloride on C-S-H dominates its transport into matured cement paste. However, the surface electrical properties of C-S-H have not properly determined yet. Thus, the main purpose of this study is to determine the amount of surface site on C-S-H and its associated equilibrium constants. The objectives are achieved through experimental and modeling techniques. A two-layer surface complexation model was used to determine the surface site density of C-S-H（with Ca/Si of 0.6, 0.83 and 1.0）and the equilibrium constant values for dissociation of silanol sites and adsorption of calcium on silanol sites. The parameters are derived by fitting the titration and calcium adsorption experimental data to the model results. It can be inferred that the estimated parameters in this study will provide insight into the prediction of adsorption and diffusion of not only chloride but also other ions in cementitious materials.
• Ion-cement hydrate interactions govern multi-ionic transport model for cementitious materials
  Elakneswaran Y.; Iwasa A.; Nawa T.; Sato T.; Kurumisawa K.
  Cement and Concrete Research, 40, 12, 1756, 1765, Elsevier, 2010
  English, 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 multi-component 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.
• Electrokinetic potential of hydrated cement in relation to adsorption of chlorides
  Y. Elakneswaran; T. Nawa; K. Kurumisawa
  CEMENT AND CONCRETE RESEARCH, 39, 4, 340, 344, Apr. 2009
  English, Scientific journal
• Zeta potential study of paste blends with slag
  Y. Elakneswaran; T. Nawa; K. Kurumisawa
  CEMENT & CONCRETE COMPOSITES, 31, 1, 72, 76, Jan. 2009
  English, Scientific journal
• INFLUENCE OF ELECTROLYTES ON SURFACE CHARGE DENSITY OF PASTES
  ELAKNESWARAN Yogarajah; NAWA Toyoharu; KURUMISAWA Kiyofumi; HAYASHI Ami
  セメント・コンクリート論文集, 61, 108, 114, 20 Feb. 2008
  English
• 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, [Peer-reviewed]
  English, International conference proceedings
• Surface Charge of Hardened Cement Paste Determined by Membrane Potential
  Yogarajah Elakneswaran; Toyoharu Nawa; Kiyofumi Kurumisawa; Koji Fushimi
  Cement Science and Concrete Technology, 60, 111, 117, 2006, [Peer-reviewed]
  English, Scientific journal

• CO₂を注入したアミン溶液を練混ぜ水に用いたモルタルの特性評価
  武部幹太; エラクネス ヨガラジャ; 北垣亮馬; 齊藤亮介, セメント技術大会講演要旨(CD-ROM), 79th, 2025
• 高炉スラグ微粉末を用いたアミンによる炭酸化促進及びスラグセメントペーストの特性評価
  武部幹太; エラクネス ヨガラジャ; 北垣亮馬; 齊藤亮介, コンクリート工学年次論文集(CD-ROM), 47, 2025
• Exploring the Limit of Low-Salinity Waterflooding in a Carbonate Reservoir with Low Total Acid Number Oil
  T. Uetani; M. Takeya; Y. Elakneswaran, APOGCE 2024, 14, 11 Oct. 2024
  Abstract
  
  This paper presents a workflow for designing the optimal injection brine composition for an offshore carbonate reservoir. The crude oil from this reservoir has a very low total acid number (0.01 mg KOH/g), leading to the expectation that injecting diluted seawater would not be an effective enhanced oil recovery (EOR) fluid. To address this, we designed a water composition that maximizes electrostatic repulsion (total disjoining pressure) at the oil-rock interface. This was achieved by combining two surface complexation models (oil-water and calcite-water interfaces), tuned to represent the reservoir conditions, with the extended DLVO theory. The total disjoining pressure was calculated for more than 30 different brine compositions, and we selected the one that demonstrated the highest value. The optimized injection brine, termed ‘repulsive’ water, was then evaluated in the laboratory for its oil recovery performance. Both spontaneous imbibition tests and coreflooding tests showed limited success with the repulsive water, yielding additional oil recovery factors of only 1-2%. We believe that the poor oil recovery results from insufficient repulsion at the oil-rock interface. Greater repulsion would be necessary for improved oil recovery, but this was not achieved within the scope of this study. Additionally, injecting diluted seawater (by fifty times) also failed to yield promising oil recovery results. Based on these findings, we conclude that low-salinity waterflooding is not a viable EOR option for the studied carbonate reservoir., SPE
• 高炉スラグに対するアミンを用いたCO₂固定化の検証
  武部幹太; エラクネス ヨガラジャ; 北垣亮馬; 依田侑也, セメント技術大会講演要旨(CD-ROM), 78th, 2024
• DAC Coating Technology: Direct Air Capture and Corrosion Prevention in Concrete Structures
  Keiichi Yano; Ryosuke Saito; Yuya Yoda; Masato Tsujino; Akira Nishida; Yogarajah Elakneswaran; Hisanori Senboku; Masatoshi Sakairi; Koji Fushimi; Ryoma Kitagaki, SSRN Electronic Journal, 2024
  Elsevier BV
• アミンを活用した鉄筋コンクリートに対するCO₂固定促進手法—Promoting CO₂ Fixation for Reinforced Concrete Using Amine—小特集 脱炭素・資源循環・自然共生
  齊藤 亮介; 矢野 慧一; 依田 侑也; 辻埜 真人; 西田 朗; エラクネスワラン ヨガラジャ; 仙北 久典; 坂入 正敏; 伏見 公志; 北垣 亮馬, 清水建設研究報告, 101, 7, 14, Dec. 2023
  東京 : 清水建設技術研究所, Japanese
• アミンを利用した既設コンクリートに対するCO₂固定促進手法—特集 ふるくてあたらしい中性化/炭酸化の新展開 ; 既存構造物での検討
  齊藤 亮介; エラクネス ヨガラジャ; 辻埜 真人; 北垣 亮馬, コンクリート工学, 61, 9, 854, 858, Sep. 2023
  東京 : 日本コンクリート工学会, Japanese
• 水分が光劣化挙動に与える影響-架橋ウレタンのマルチスケール劣化解析-
  石田崇人; 北垣亮馬; ELAKNESWARAN Yogarajah; 萩原英昭, マテリアルライフ学会研究発表会,特別講演会予稿集, 31st, 2020
• エマルジョンとナノ粒子による高炉スラグ硬化体の初期強度・耐凍害性の改善
  名和豊春; 胡桃澤清文; ELAKNESWARAN Y.; 佐川孝広; 西祐宜, 環境助成研究成果 概要集 第38回・2017年度分:11件 第39回・2018年度分:23件 令和2年度, 2020
• 汚染水処理から発生する使用済み合成ゼオライト及びチタン酸塩の長期保管における固化マトリックスとしてのジオポリマーの適用性
  戸田賀奈子; SOONTHRONWIPHAT Natatsawas; TWO Hnin Wint Wint; 小林佑太朗; 黒田知眞; 森永祐加; 胡桃澤清文; YOGARAJAH Elakneswaran; 杉山隆文; KE Xinyuan; PROVIS John; 佐藤努, 日本原子力研究開発機構JAEA-Review(Web), 2018-017, 2018
• Physical, chemical, and mineralogical characteristics of blast furnace slag on durability of concrete
  Elakneswaran Yogarajah; Toyoharu Nawa; Toshifumi Igarashi, THE THIRD INTERNATIONAL CONFERENCE ON SUSTAINABLE INFRASTRUCTURE AND BUILT ENVIRONMENT (SIBE 2017), 147, 2018, [Peer-reviewed]
  English
• Ca(OH)₂溶液におけるモンモリロナイトの溶解速度—pHおよびC‐S‐H生成の影響—
  木嶋達也; 中林亮; YOGARAJAH Elakneswaran; 小田治恵; 大竹翼; 佐藤努; 米田哲朗, 日本原子力学会秋の大会予稿集(CD−ROM), 2012, ROMBUNNO.B50, 622, 03 Sep. 2012
  Ca(OH)2溶液におけるモンモリロナイトの溶解速度をフロースルー実験により算出した。溶解速度に対するpHの影響は先行研究で明らかにされているNaOH溶液におけるものと同様であった。一方、pHやCa濃度の条件によっては二次生成物としてC-S-Hが生成することが認められた。C-S-Hの生成がモンモリロナイトの溶解速度にどのような影響を与えるかを地球科学モデリングによって評価した。, Atomic Energy Society of Japan, Japanese
• Prediction of ionic adsorption and multi–ionic transport in cementitious materials
  Elakneswaran Yogarajah; Nawa Toyoharu; Sato Tsutomu; Kurumisawa Kiyofumi; Iwasa Akihito, Proceedings of Annual / Fall Meetings of Atomic Energy Society of Japan, 2010, 0, 836, 836, 2010
  Cementitious materials are being used for encapsulation, back filling, and grouting purposes in deep geological repositories of long – lived radioactive waste. The long – term performance of cementitious materials has been investigating for safety disposal of radioactive waste. The durability performance of cementitious materials is mainly determined by resistance to transport of aggressive substances, however remain poorly understood. In this study, a thermodynamic integrated model has been developed to simulate multi-ionic transport in cementitious materials with considering ionic adsorption. The model has been validated against measured experimental data., Atomic Energy Society of Japan, Japanese
• Influence of surface charge on ingress of chloride ion in hardened pastes
  Y. Elakneswaran; T. Nawa; K. Kurumisawa, MATERIALS AND STRUCTURES, 42, 1, 83, 93, Jan. 2009
  English
• An integrated model to predict the relations between electrical double layer properties and chloride ingress in cement - Based materials
  Y. Elakneswaran; T. Nawa; K. Kurumisawa, RILEM Workshop on Long-Term Performance of Cementitious Barriers and Reinforced Concrete in Nuclear Power Plants, NUCPERF 2009, 135, 142, 01 Jan. 2009
• 高炉スラグ微粉末混入ペーストの塩分浸透性と微細構造
  胡桃澤清文; 名和豊春; ELAKNESWARAN Y., コンクリート技術シリーズ, 74, 2007

• 大学院共通授業科目（一般科目）：自然科学・応用科学, 2024年, 修士課程, 大学院共通科目
• 資源生産システム, 2024年, 修士課程, 工学院
• 資源生産システム特論, 2024年, 修士課程, 工学院
• 資源生産システム特論, 2024年, 博士後期課程, 工学院
• 資源化学Ⅰ, 2024年, 学士課程, 工学部
• 資源化学Ⅱ, 2024年, 学士課程, 工学部
• 資源循環システム実験Ⅰ, 2024年, 学士課程, 工学部
• 資源循環システム実験Ⅲ, 2024年, 学士課程, 工学部

• 燃料デブリの除去にむけた頑健で将来性のある閉じ込め剤としてのメタカオリンベースのジオポリマーの技術開発とその仕様
  Nov. 2023 - Mar. 2026
  エラクネス ヨガラジャ、佐藤努, 菊池亮佑, 岡田 尚, 大杉 武史, 佐藤 淳也, 平木 義久
  文部科学省 英知を結集した原子力科学技術・人材育成推進事業（国際協力型廃炉研究プログラム（日英原子力共同研究））, Principal investigator, 23815826
• 高い流動性および陰イオン核種保持性を有するアルカリ刺激材料の探索と様々な放射性廃棄物の安全で効果的な固化
  Nov. 2019 - Mar. 2022
  佐藤 努; エラクネス ヨガラジャ
  文部科学省 英知を結集した原子力科学技術・人材育成推進事業（国際協力型廃炉研究プログラム（日英原子力共同研究））
• Predicting long-term durability performance of cement systems from the nanost ructure and properties of calcium aluminosilicate hydrate (C-A-S-H) gels
  Grants-in-Aid for Scientific Research
  01 Apr. 2018 - 31 Mar. 2021
  Elakneswaran Yogarajah
  The density of the surface groups was determined by analysing the structure of C-S-H and C-A-S-H through 27Al and 29Si MAS NMR. The surface sites of ≡SiOH and ≡AlOH are available in C-A-S-H whereas C-S-H has ≡SiOH groups. The incorporation of aluminium decreases the number of total adsorption sites in C-A-S-H. Furthermore, the site density increased with Ca/(Si+Al). To understand the C-A-S-H/solution interface, a triple-layer surface complexation model was developed and the associated equilibrium constants for deprotonation, calcium, and chloride adsorption were determined by fitting the experimental data of potentiometric titration and zeta potential measurement results. The estimated surface complexation modelling parameters were verified by predicting the experimental data of calcium and chloride adsorption on C-S-H and C-A-S-H.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 18K04297
• 英知を結集した原子力科学技術・人材育成推進事業 汚染水処理で発生する合成ゼオライトと チタン酸塩のセメント固化体の核種封じ込め性能の理解とモデル化 およびその処分システムの提案
  Nov. 2016 - Mar. 2019
  佐藤 努; エラクネス ヨガラジャ
  文部科学省 国家課題対応型研究開発推進事業 英知を結集した原子力科学技術・人材育成推進事業, Coinvestigator not use grants
• Surface chemistry of calcium aluminosilicate hydrate (C-A-S-H) for ions immobilization and transport in low carbon cementitious materials
  Grants-in-Aid for Scientific Research
  01 Apr. 2016 - 31 Mar. 2018
  Yogarajah Elakneswaran
  Alumina-rich supplementary cementitious materials produces aluminium incorporated calcium silicate hydrate, C-A-S-H. The electrostatic properties of the C-A-S-H gel are significantly different from the conventional C-S-H, which may affect the durability performance. This research project focuses on the surface electrical properties mainly surface charge of C-S-H and C-A-S-H. A methodology was proposed to determine the properties from the experimental data and fitting the data to a surface complexation model. Subsequently, the model was verified with experimental data focused on chloride adsorption considering corrosion of reinforcement in concrete. The developed model were coupled with the hydration and reactive transport models to predict the ionic ingress in cementitious materials. The model was verified with experimental data for chloride ingress in slag-blended cementitious materials. The methodology will be applied to C-A-S-H to understand the its structure and the properties.
  Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, 16K18129