硅质机制砂改性剂的机理研究与应用

硅质机制砂由于石粉含量高,石粉吸附减水剂能力强,制备的混凝土工作性较差。通过制备出一种小分子表面活性剂(简称改性剂),来改善硅质机制砂出现的问题。首先分析了机制砂石粉的成分、形貌等特点。比较了掺加改性剂与不掺加改性剂时不同石粉含量的砂浆的扩展度,并应用在两种硅质机制砂混凝土中。最后利用粒度分析、显微粒度图像、SEM、Zeta电位等方法,分析了改性剂的作用机理。实验结果表明:硅质机制砂改性剂可以有效地增加砂浆扩展度,提高混凝土的初始坍落度,减少混凝土的坍落度损失,并且对强度没有太大影响。改性剂主要通过超强分散与吸附络合作用来提高硅质机制砂混凝土的工作性,减少负面影响。

Mechanism Study and Application of the Modifier for Siliceous Machine-made Sand

Because of the high content of stone powder and the ability of stone powder to absorb water reducing agent, the workability of concrete prepared by siliceous machine-made sand is poor. A small molecule surfactant, referred to as modifier, was prepared to improve the occurrence of siliceous sand. Firstly, the composition, morphology and characteristics of machine-made sand powder were analyzed. Then, the expansion degree of mortar of different stone powder with and without the addition of modifier was compared and applied in two kinds of siliceous machine-made sand concrete. Finally, the mechanism of modifier was analyzed by means of particle size analysis, micrograph, SEM and Zeta potential. Experimental results show that the modified agent of siliceous mechanism sand can effectively increase the degree of expansion of concrete mortar which improve the initial slump effectively and reduce slump loss of concrete. And it has little influence on the strength. The modified agent is mainly used to improve the workability of the siliceous mechanism sand concrete by complexation with strong dispersion and adsorption,and reduce the negative influence.