不同养护温度下高强高性能混凝土早龄期自收缩特性

Behavior of autogenous shrinkage of high strength-performance concrete at early ages under different curing temperatures

以水胶比分别为0.30、0.40和0.50的混凝土为对象,采用改进的测量方法实验评价了5、20、35℃等3种养护温度对高强高性能混凝土自收缩的影响。结果表明,养护温度越高,自收缩增长越快,其值越大,且水胶比越低、龄期越早表现得越显著。抗压强度和弹性模量受养护温度的影响也大致符合同一规律。高强高性能混凝土早龄期自收缩的温度依存性是胶凝材料的水化反应和自干燥的强温度相关性的表现。

In this paper,with 3 kinds of mixture proportions whose water-binder ratio are 0.30,0.40 and 0.50, and 3 kinds of curing temperatures at 5,20 and 35 ℃,the effects of curing temperature on autogenous shrinkage of high strength/performance concrete are experimentally investigated based on an improved testing method. The results show that the higher the. curing temperature,the faster the increasing rate and the higher magnitude of autogenous shrinkage, especially at earlier ages and for mixtures with a lower water-binder ratio. A similar characteristic is existed on compressive strength and elastic modulus. Temperature dependence of autogenous shrinkage indirectly reflects interplay between cement hydration and self-desiccation in terms of environmental temperature and/or concrete temperature.