混凝土湿度和干缩变形及应力特性的细观模型分析

基于扩散理论的混凝土非线性湿度理论和干缩应力的有限元数值计算方法，将混凝土视为砂浆和骨料所组成的多相复合材料，对比数值计算，探讨了各相材料湿度特性差异对混凝土细观和宏观湿度特性、干缩变形和干缩应力的影响，认为只有考虑了这种材料特性差异的细观模型和计算方法才能得到较符合真实情况的混凝土湿度、干缩和干缩应力的分布规律，有助于更好地理解和诊断混凝土早期和后期裂缝产生的机理、启裂点位置和防止方法。所采用的细观研究方法也适用于混凝土温度应力和自生体积变形致裂问题的研究。

Analysis of concrete moisture dry shrinkage and stress based on mesoscopical model

Based on non-linear moisture of diffusion theory and numerical FEM calculation method for dry shrinkage stress, concrete is assumed to be a three-phase material composite including matrices, aggregates and aggregate-matrix interfaces. The macroscopical and mesoscopical moisture properties of concrete composite depend on the relevant characteristics of the different phases. Numerical results of the dry shrinkage and stress related are compared when the difference of material characteristics between matrices and aggregates has been considered or not. The distributions of moisture, drying shrinkage and dry stress are obtained more reasonably and realistically by using the mesoscopical model and calculation method considering the different characteristics of the material phases. It is benefited for us to understand the cracking mechanism, location of the initial cracking and the suitable measures for preventing cracks occurring at early and later ages. Besides, the present mesoscopical study is also suitable to study crack phenomenon induced by other reasons such as thermal load and autogenous shrinkage.