橡胶混凝土的抗裂性能和弯曲变形性能

Cracking-resistance and flexural property of rubberized concrete

通过净浆、砂浆和混凝土3个层面的试验研究,探讨了橡胶混凝土的抗裂性能和弯曲变形特性。根据圆环试件的开裂时间,对3种水灰比(0.3,0.4,0.5)水泥净浆中掺入不同体积含量橡胶颗粒(10%,15%,20%,30%,50%)后的开裂敏感性进行了对比分析。结果表明,在水泥净浆中掺入橡胶颗粒可以显著延缓试件的开裂时间,提高抗裂性,延缓时间随着橡胶颗粒掺量的增加和水灰比的增大而延长。弯曲试验考察了4个橡胶颗粒体积含量(8%,16%,21.4%,32%)砂浆试件和3个橡胶颗粒体积含量(10%,12.5%,15%)混凝土试件的弯曲变形性能。结果表明,含橡胶颗粒的砂浆试件和混凝土试件在弯曲过程中会产生明显的塑性变形,试件不会在承受最大荷载时产生脆性断裂,而是经过较大的塑性变形后延性破坏。与基准试件相比,砂浆试件和混凝土试件破坏时的极限变形值均有大幅度提高。

The cracking-resistance and flexural property of the rubberized concrete were investigated based on the tests of paste, mortar and concrete specimens. The cracking-resistance was evaluated based on the cracking time of a ring specimen, which was prepared by incorporating waste tire rubber particles in the cement paste, and three different water-cement ratios （0.3, 0.4, 0.5） and five different rubber volume fractions（10%, 15%, 20%, 30%, 50%） were used. The results show that the addition of rubber particles delays the cracking time and improves the cracking-resistance of the specimens and the delayed time increases with the increase of the water-cement ratio and the volume fraction of rubber particles. The flexural properties were evaluated based on the bending tests of both mortar and concrete, four rubber volume fractions （8%, 16%, 21. 4%, 32%） were used for mortar and three rubber fractions （10 %, 12.5 %, 15 %） for concrete. The results show that the rubberized mortar and concrete spec- imen exhibited ductile failure and underwent significant deformation before fracture. The ultimate deformations of both mortar and concrete specimen increase substantially compared to the control specimens.