掺入钢纤维的活性粉末混凝土早期抗裂性能

Early cracking resistance of reactive powder concrete mixed with steel fiber

为提高活性粉末混凝土(RPC)的早期抗裂性能,从而提高工程的耐久性,降低后期维修成本,提出在RPC中掺入2%的钢纤维,采用约束圆环装置和千分表,用单因素法分析掺入钢纤维对RPC早期约束钢环应变和自由收缩的影响.结果表明,与不掺纤维的RPC相比,在RPC中掺入2%的钢纤维可以明显降低约束钢环应变,并且延缓裂缝出现的时间;掺入钢纤维的RPC的自由收缩应变也有着显著的降低,初期收缩应变发展很快,随后慢慢降低,最后趋于平稳.

In order to enhance the early cracking resistance of Reactive Powder Concrete(RPC),thus improving the durability of the project and reducing the post maintenance cost.In this paper,we propose to incorporate 2%steel fiber in RPC,and the effect of incorporating steel fibers on the early restrained steel ring strain and free shrinkage is investigated by single-factor method using restrained ring devices and micrometers.The result shows that 2%steel fibers in RPC can significantly reduce the restrained steel ring strain and delay the appearance of cracks compared with the RPC without fibers.The free shrinkage strain of RPC with steel fibers also has a remarkable reduction,and the shrinkage develops rapidly at the beginning,then decreases slowly and finally stabilizes.