東京大学 · 工学
伊東哲也教授の研究室では、セメントコンクリート材料の長期的な耐久性を予測するため、化学・熱・水分の連成挙動を高精度にモデル化する研究が進められています。特に、二酸化炭素の侵入に伴うpH低下や炭酸化反応の進行、微細な空隙構造の変化を時間経過とともに統合的に解析する数値シミュレーション手法の構築が主な研究テーマです。また、異なる養生条件や建材配合に応じた耐久性の差異を解明し、実用的な設計指針の構築にも貢献しています。
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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