温度-约束共同作用下的混凝土裂缝发展特性分析

Analysis of Concrete Crack Development Characteristics Under Temperature-constraint Interaction

针对混凝土开裂问题,建立了混凝土有限元损伤计算模型,揭示了混凝土浇筑块在不同边界约束条件下的裂缝发展规律,通过对比裂缝特性,选出了最有利于混凝土抗裂性能的边界约束条件。为检测高效抗裂剂的抗裂效果,采用全站扫描仪对混凝土开裂情况进行激光扫描。研究表明:裂缝的特征和发展规律与边界约束条件密切相关,当只有底部约束时,混凝土裂缝的数量较多,但尺寸比较小;当三边约束时,裂缝数量较少,但会形成主裂缝,尺寸较大;当四边均约束时,裂缝数量较多且尺寸较大。因此,通过设置后浇筑带等措施可优化边界约束条件,降低混凝土裂缝数量和尺寸。同时,在混凝土中掺和高效抗裂剂可有效提高混凝土的抗裂性能。

In view of the concrete cracking problem, the finite element calculation model of concrete damage is established, and the crack development law of concrete pouring block under different boundary constraints is revealed. By comparing the crack characteristics, the boundary constraint conditions which are most beneficial to the crack resistance of concrete are selected. To test the anti-cracking effect of high-efficiency anti-cracking agent, laser scanning is carried out on concrete cracking by whole station scanner. The analysis shows that: the characteristics and development law of cracks are closely related to the boundary constraints;when there are only bottom constraints, the concrete crack number is large, but the size is relatively small;when the three sides are constrained, the crack number is less, but the main cracks will be formed, and the size is larger;when the four sides are constrained, the number of cracks is more and the size is larger. Therefore, the boundary constraint conditions can be optimized and the number and size of concrete cracks can be reduced by setting post-pouring-belt and other measures. At the same time, the crack resistance of concrete can be effectively improved by adding high-efficiency anti-cracking agent into concrete.