掺花岗岩石粉砂浆自收缩性能演变规律研究

Autogenous Shrinkage Performance Evolution Law of Mortar Mixed with Granite Powder

为提高花岗岩石粉利用率,在分析粉磨时间对花岗岩石粉颗粒特征影响规律的基础上,系统研究了花岗岩石粉掺量及粉磨时间对砂浆自收缩性能的影响规律,并采用灰熵法分析了影响掺花岗岩石粉砂浆自收缩性能的主要因素,最后采用微观测试方法揭示花岗岩石粉对砂浆自收缩性能的影响机理。结果表明:随着粉磨时间增加,石粉颗粒细度逐渐增大,粒径小于10μm的颗粒含量增多,粒径大于40μm的颗粒含量降低,掺花岗岩石粉砂浆自收缩变形逐渐增大;随着花岗岩石粉掺量增加,砂浆自收缩变形呈先增大后减小的趋势;适当减小粒径小于20μm的花岗岩石粉颗粒含量,有利于提高掺花岗岩石粉砂浆的自收缩活性指数;花岗岩石粉主要通过影响砂浆内部水化产物种类及数量,进而影响砂浆自收缩变形规律。

In order to improve the utilization rate of granite powder,based on the analysis of the influence of grinding time on particle characteristics of granite powder,the influences of granite powder dosage and grinding time on autogenous shrinkage performance of mortar were systematically studied.The main factors affecting the self shrinkage performance of mortar with granite powder were analyzed using grey entropy method.Finally,microscopic testing methods were used to reveal the mechanism of the influence of granite powder on self shrinkage performance of mortar.The result show that with the increase of grinding time,the fineness of stone powder particles gradually increases,the content of particles with a particle size less than 10μm increases,the content of particles with a particle size greater than 40μm decreases,and the self-contraction deformation of granite-doped stone powder mortar gradually increases.With the increase of granite powder content,the self shrinkage deformation of mortar shows a pattern of increasing first and then decreasing.Appropriately reducing the dosage of granite powder particles with particle size less than 20μm is beneficial for improving the self shrinkage activity index of mortar mixed with granite powder.The granite powder mainly affects the type and quantity of hydration products inside mortar,thereby affecting its self shrinkage deformation law.