高韧性纤维增强水泥基复合材料的收缩变形

Shrinkage distortion of fiber-reinforced high-ductility cementitious composites

通过试验研究了砂灰比、水灰比、纤维种类和减缩剂对高韧性纤维增强水泥基复合材料(ECC)收缩变形的影响.结果表明:随着砂灰比的增大,ECC收缩应变值逐渐减小;随着水灰比的增大,ECC收缩应变值逐渐增大;国产PVA纤维对控制ECC早期收缩变形有较明显的效果,而日本产的高弹性模量PVA纤维对控制ECC后期收缩变形效果显著;水灰比为0.40时,混杂纤维对控制ECC收缩变形的效用比单独掺入国产PVA或日本产PVA好;水灰比为0.40时,掺入减缩剂可使ECC收缩应变约减少200×10-6,可见减缩剂控制ECC收缩变形效果显著.

The effects of sand-to-cementitious materials ratio （S/C）, water-to-cementitious materials ratio （W/C）, fiber species and using a reduction additive on the shrinkage distortion of fiber-reinforced high-ductility cementitious composites （ECC） were investigated. Experimental results show that the shrinkage strain of ECC reduces with increasing S/C and enlarges with increasing W/C. Chinese PVA fibers effectively control the early stage shrinkage distortion of ECC, but Japanese PVA fibers of high Young’s modulus have great effect on the final stage shrinkage distortion of ECC. Hybrid fibers can better control the shrinkage distortion of ECC than Chinese or Japanese PVA fibers separately when the W/C is 0.40. The shrinkage strain probably reduces 200×10^-6 by using a reduction additive, and the reduction additive can also effectively control the shrinkage distortion of ECC at the W/C of 0.40.