高强混凝土的自收缩试验研究

Experimental Study on Autogenous Shrinkage of HighStrength Concrete

论述了混凝土自收缩产生的机理、高强混凝土自收缩的特点及其危害性。在对比和分析国内外自收缩测定方法的基础上，建立了较为科学的自收缩测定方法。针对高强混凝土自收缩大，而且集中在早期发生的特点，本文还介绍了掺用粉煤灰通过改善高强混凝土的硬化速度而降低高强混凝土早期自收缩的探索性试验结果。初步试验表明：随着粉煤灰掺量的增加，高强混凝土的自收缩减小，并有“滞后效应”；粉煤灰掺量超过２０％后，降低自收缩的效果并不明显。

This paper discusses the mechanism of autogenous shrinkage of concrete,the characteristics and disadvantage of autogenous shrinkage of highstrength concrete.A new measuring method for autogenous shrinkage was established on the basis of the analysis of other existing methods.Fly ash was blended to reduce the large autogenous shrinkage of highstrength concrete,especially at early ages,through the improvement of hardening speed.Preliminary experimental results show the decrease of autogenous shrinkage of highstrength concrete and a lagging effect with the increase of fly ash content.However,the effect of reducing autogenous shrinkage by incorporating fly ash became insignificant after its addition was over 20 percent of total binder content.