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试验研究发现高性能混凝土容易产生早期收缩裂缝,理解高性能混凝土早期收缩的机理,是改善高性能混凝土早期变形行为的基础。从湿度迁移的微观机理角度考察混凝土干缩变形,进而综合水泥水化热、环境温度场、以及荷载作用的数值仿真理论已经用于分析普通混凝土的早期变形特征。本文模拟分析了高性能混凝土试件在自由收缩条件下的变形和在约束收缩条件下的应力,同时,通过对比高性能混凝土和普通混凝土的收缩变形模型中的参数,分析了这些参数的选取原则。研究表明,数字仿真值在一定程度上可以表征高性能混凝土的实验室试验,计算结果在早龄期(2天以前)与试验数据的差别显示高性能混凝土微观结构发展的复杂性有待深入研究。
Experimental study found that high-performance concrete prone to early shrinkage cracks, early understanding of high-performance concrete shrinkage mechanism is to improve the early deformation of high-performance concrete foundation. From the perspective of microscopic mechanism of moisture transfer, the shrinkage deformation of concrete is investigated, and then the numerical simulation theory of cement hydration heat, ambient temperature field and load is used to analyze the early deformation characteristics of ordinary concrete. In this paper, the deformation of high performance concrete specimens under free shrinkage and the stress under the condition of shrinkage are simulated and analyzed. At the same time, by comparing the parameters in the shrinkage deformation model of high performance concrete and ordinary concrete, the principle of choosing these parameters . The results show that the digital simulation value can characterize the laboratory test of high performance concrete to a certain extent. The difference between the calculated results and the experimental data in the early age (2 days ago) shows the complexity of the development of high performance concrete microstructures needs further study.