改性废旧橡胶粉对水泥胶砂性能的影响

Effect of Modified Rubber Powder on Performances of Cement Mortar

关键词:  改性胶粉  水泥胶砂  CH含量  界面过渡区形貌  孔隙结构

Key words:  modified rubber powder  cement mortar  CH content  interface transition zone morphology  pore structure

摘要:

为了探究改性废旧橡胶粉（简称改性胶粉）对水泥胶砂性能的影响及作用机理,利用四因素三水平正交试验研究了改性胶粉掺入顺序、粒径、掺量及改性方法对水泥胶砂性能的影响,通过极差分析确定了最佳条件组合;通过热重分析、扫描电子显微镜、压汞试验研究了改性胶粉水泥胶砂CH含量、界面过渡区形貌及孔隙的变化.结果表明：掺加改性胶粉可以降低水泥胶砂中CH的发育程度、界面过渡区的厚度以及凝胶孔体积,从而提升其干缩性能和韧性;掺加改性胶粉以后,水泥胶砂的水化进程减缓,大孔体积增大,力学性能降低;采用化学改性的301μm胶粉,以1%掺量按后掺入的顺序掺入水泥胶砂后,其综合性能最好.

Abstract:

In order to explore the effect of modified rubber powder on performances of cement mortar and its mechanism, four factors i.e. mixing order, particle size, modified rubber powder content and modification method, and their three levels of orthogonal experiment were used. The performances of cement mortar in different conditions were test. The optimal combination of conditions was determined through range analysis. Thermogravimetric analysis, scanning electron microscope and mercury injection tests were used to measure the CH content, interfacial transition zone morphology and pore structure. The test results showed that adding modified rubber powder could reduce CH content, interface transition zone thickness and gel pore volume of cement mortar and improve its drying shrinkage and toughness. However, the adding modified rubber powder could slow down the hydration process and increase the macropore volume of cement mortar, which reduce its strength slightly. So, it was found that the performances of cement mortar with the 1% chemical modification of 301μm powder using after mixed order were the best.