Evaluation of Accumulated Damage in Reinforced Concrete at Early Age

钢筋混凝土早期累积损伤的评估

• 批准号: 01850107
• 负责人: OZAWA Kazumasa
• 金额: $ 4.35万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B).
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01850107/
• 关键词: Hydration,; Temperature-dependency,; Activation energy,; Accumulated damage; Water movement,; Drying shrinkage,; Durability,; Early-age concrete; 非線形温度解析; 硬化収縮; 沈下ひびわれ; 水和反応; 引張剛性; Hydration,; Temperature-dependency,; Activation energy,; Accumulated damage; Water movement,; Drying shrinkage,; Durability,; Early-age concrete; 非線形温度解析; 硬化収縮; 沈下ひびわれ; 水和反応; 引張剛性

The objective of this study is to evaluate the accumulated damage and micro fracture in concrete caused by hardening and drying shrinkage, heat and water transfer and external stress at early age, and to develop the new system for evaluating the time-dependent performance for durability of concrete structures.1. Time-dependent and path-dependent hydration of cementThe evaluation method for activation energy of cement in concrete was developed. The model for path-dependent hydration of cement at any temperature and any any age was proposed.2. Activation energy and mix proportionIt was clarified that the activation energy representing temperature dependency of cement is controlled by the dispersion of cement in concrete. General relationship between mix proportion and activation energy was successively proposed.3. Evaluation of accumulated damageEvaluation method of accumulated damage caused by hardening and drying shrinkage and segregation in cover concrete around reinforcing bars was proposed with use of tension-stiffness of concrete. Resistance to the damage was also successively evaluated by average tensile strength, average tensile plastic deformation and bond deterioration.4. Water movement and drying shrinkage in concreteModel for predicting water movement in concrete at fresh state and after being hardened was proposed, which affects the damage and micro fracture in concrete. Relationship between water movement by drying and shrinkage in concrete was clarified based on the micro-structure of concrete.

这项研究的目的是评估由硬化和干燥收缩，热量和水分转移以及早期的外部压力引起的混凝土中的累积损伤和微断裂，并开发了新的系统，以评估混凝土结构持续性的时间依赖性性能。1。开发了水泥的评估方法的时间依赖性和路径依赖性水合作用水泥化学方法。提出了水泥在任何温度和任何年龄段的水泥水合的模型。2。激活能和混合比例阐明了代表水泥温度依赖性的活化能由水泥在混凝土中的分散体控制。混合比例和激活能量之间的一般关系连续提出。3。通过使用混凝土的张力 - 状态，提出了盖覆盖混凝土覆盖混凝土中的累积损伤方法的累积损害评估方法。还通过平均拉伸强度，平均拉伸塑性变形和粘结恶化对损伤的抵抗力也依次评估。4。提出了混凝土模型中的水运动和干燥收缩，以预测新鲜状态下混凝土的水运动，并提出硬化后，这会影响混凝土中的损伤和微断裂。根据混凝土的微结构，阐明了通过干燥和收缩来通过干燥和收缩的水之间的关系。