The University of Tokyo · Engineering
Professor Tetsuya Ishida's research lab specializes in the multi-scale modeling and experimental analysis of cement-based materials, focusing on the durability and long-term performance of concrete under various environmental conditions. The lab investigates key degradation mechanisms such as carbonation and chloride ingress, with particular emphasis on the coupled thermo-hydro-mechanical-chemical (THMC) processes that govern these phenomena. By integrating advanced computational modeling with experimental techniques like XRD, mercury intrusion porosimetry, and pore solution extraction, the lab develops predictive frameworks for assessing the evolution of microstructure and chemical composition in cementitious materials. Their work aims to establish unified, physics-based models that accurately simulate carbonation and ion binding behavior under diverse curing and environmental conditions.
Figures are computed from collected data and may differ slightly.
本研究は, 種々の環境作用を受ける構造物中のセメント硬化体のpH変動, 組織の変性を, 時間軸と共に追跡する一般化手法の確立を目指したものである. ここでは特に, 二酸化炭素の侵入に伴うpH低下の評価を主たる対象とし, 二酸化炭素の移動・平衡, 反応に関与する物質の解離・イオン平衡, 炭酸化反応に対してモデル化を行った. また, 各現象の数量化に用いる空隙構造, 内部水分状態, 水和生成物量・種類等は, 熱力学モデルと連成解析システムによって得た. 提案手法により, 異なる養生条件, 環境条件及び配合に対して, 炭酸化進行現象が統一した枠組みで追跡可能になった.
In order to predict the chemo-physical process of carbonation, a finite element based computational method is implemented based upon multi-phase/scale governing equations of moisture and flux of both heat and carbon dioxide. Influencing parameters of carbonation involving reaction rate, CO2 diffusivity and the reduction of porosity are discussed. It is found that such modeling can accurately show high nonlinearity among carbonation reaction, pore structure development and moisture distribution i
The authors experimentally studied the chloride binding capacity of mortar specimens made with various combinations of Portland cement, blast furnace slag, and pozzolans. In the experiment, a pore liquid extraction method, chloride titration test, a quantitative analysis of Friedel's salt based on the XRD method, and a mercury intrusion porosimetry test were conducted in order to measure chloride ions, adsorbed chlorides on the pore wall, and solid-phase chlorides (Friedel's salt), separately. I
A carbonation model based on thermo-hygro physics is presented in this paper. Reaction of C-S-H gel was newly added to the existing model as well as calcium hydroxide reaction, and a micro-pore structure model for carbonated concrete was improved by considering volume change and surface-area increase of hydrated products. The proposed model coupled with moisture equilibrium/transport gives reasonable predictions for carbonation progresses under low and high CO2 concentrations in a unified manner
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