含硫酸盐类固废对硅酸盐水泥水化影响研究

Effects of Sulfate-Containing Solid Wastes on Hydration of Portland Cement

本文研究了不同种类的含硫酸盐固废对硅酸盐水泥水化的影响,测试了含硫酸盐固废水泥力学性能、凝结时间、线性膨胀率随SO_(3)含量变化的规律,采用化学结合水、XRD和SEM等测试手段揭示了不同含硫酸盐固废对硅酸盐水泥水化的影响机理。结果表明,随SO_(3)含量增加,含硫酸盐固废水泥胶砂抗折强度和抗压强度均先增大后减小,初凝时间和终凝时间均呈增加趋势并在SO_(3)含量达到一定值后增加速度放缓,线性膨胀率均不断增大。由于不同的含硫酸盐固废的硫酸盐存在形式不同,硫酸盐溶出的速率也有差别,与水泥中铝酸三钙反应生成钙矾石(或单硫型水化硫铝酸钙)的速率和数量也不同,相同龄期下的水化程度也不同,因此不同的含硫酸盐固废对水泥力学性能、凝结时间和线性膨胀率等性能的影响存在一定差异。

In this paper,the effects of different kinds of sulfate-containing solid wastes on the hydration of Portland cement were studied.The mechanical properties,setting time and linear expansion rate of cement mixed with different kinds of sulfate-containing solid wastes were tested with the change of SO_(3)content.The influence mechanism of different sulfate-containing solid wastes on the hydration of Portland cement was revealed by means of chemical bound water,XRD and SEM.The results show that with the increase of SO_(3)content,the flexural strength and compressive strength of cement mortar containing sulfate solid waste increase first and then decrease.The initial setting time and final setting time show an increasing trend,and the increase rate slows down after the SO_(3)content reaching a certain value.The linear expansion rate continues to increase.The linear expansion rate of cement mixed with various kinds of sulfate-containing solid wastes shows an increasing trend.Due to the different forms of sulfate in different sulfate-containing solid wastes,the dissolution rate of different types of sulfate is also different.The rate and quantity of ettringite(or monosulfoaluminate hydrated)formed by the reaction with tricalcium aluminate in cement are also different,and the degree of hydration at the same age is also different.Therefore,different sulfate-containing solid wastes have different effects on the mechanical properties,setting time and linear expansion rate of cement.