高石粉含量水工混凝土干缩与微观结构的试验研究

Experimental Study on Dry Shrinkage and Microstructure of Hydraulic Concrete with High Stone Powder Content

为充分利用石粉资源,试验研究了灰岩人工砂中石粉含量(12%~28%)对水工混凝土干缩的影响,结合SEM、XRD、IR等微观测试技术,研究了石粉含量为15%、20%的水工混凝土的水化产物及其微观结构,探讨了石粉含量对水工混凝土干缩性能影响的微观机理。结果表明,不同石粉含量(12%~28%)的水工混凝土干缩率总体上呈现先增大后减小的趋势;灰岩人工砂中石粉具有活性效应,在一定程度上参与并促进体系的水化反应,改善了水工混凝土的微观结构;未参与水化反应的石粉起填充作用,使水工混凝土平均孔径减小,从而引起混凝土内部毛细管压力增大,使混凝土的干缩率增大。

The paper presents the dry shrinkage of hydraulic concrete with high stone powder containing 12%-28%.In order to ascertain the influence of stone powder content on hydration products and microstructure of the hydraulic concrete with high stone powder content,the relationship among the composition,microstructure and dry shrinkage properties of hydraulic concrete with high stone powder content is systematically studied through X-ray diffraction（XRD）,infrared spectroscopy（IR）,and scanning electron microscope（SEM）.The results shows that dry shrinkage of hydraulic concrete increases first and then decreases.Stone powder participates in the hydration reaction of hydraulic concrete,and increases the amount of hydration products.The filling effect of stone powder decreases the average pore size of concrete,result in the capillary pressure and shrinkage rate of concrete increase.