水胶比和纤维掺量对水工ECC干缩特性的影响

Effect of water binder ratio and fiber content on the drying shrinkage characteristics of hydraulic ECC

摘要

水工ECC是基于水工建筑物的抗裂需求与技术特点，将ECC应用于水工工程的重大尝试。配制了水工ECC材料，并保持拌合物扩散度相当，测试分析了水胶比和纤维掺量对水工ECC干缩特性的影响。研究表明，水工ECC的干缩变形主要发生在7 d龄期内，28 d龄期时干缩率趋于稳定；增大水胶比时，用水量略有增加，胶凝材料用量随之减小，此外，砂子用量增加，水工ECC的干缩率减小；PVA纤维有利于阻碍水分散失，抵消毛细孔负压，增加PVA纤维掺量，水工ECC的干缩率有所减小；砂子最大粒径越小，水工ECC的干缩率越大。

Abstract

Hydraulic ECC is a major attempt to apply ECC to hydraulic engineering based on the crack resistance requirements and technical characteristics of hydraulic structures. Hydraulic ECC materials with similar diffusivity are prepared, and the effect of water binder ratio and fiber content on the drying shrinkage characteristics is analyzed. The results shows that the drying shrinkage deformation of hydraulic ECC mainly occurs within 7 d age, and the shrinkage rate tends to be stable at the 28 d age. Besides, when increasing the water binder ratio, the water quantity increases slightly while the amount of cementitious material decreases, in addition, the amount of sand increases, as a result, the drying shrinkage of hydraulic ECC decreases. Moreover, PVA fibers are conducive to hinder water loss and offset the negative pressure of capillary pores, therefore, with the increase of PVA fiber content, the drying shrinkage of hydraulic ECC decreases. Furthermore, the smaller the maximum particle size of sand, the greater the drying shrinkage of hydraulic ECC.

关键词

水工ECC / 干缩特性 / 水胶比 / PVA纤维 / 砂子粒径

Key words

hydraulic ECC / drying shrinkage / water-binder ratio / PVA fiber / sand particle size

基金资助

安徽省引江济淮集团有限公司科技资助项目(YJJH-ZT-ZX-20210408381)