微珠对新型板式轨道用自密实混凝土工作性能的影响

通过混凝土扩展度、坍落度、扩展时间T_(500)、水泥净浆黏度等试验方法,研究微珠对CRTSⅢ型板自密实混凝土工作性的作用机理。结果表明,适宜的微珠掺量能够显著改善混凝土工作性,当微珠掺量为1. 5%时混凝土工作性最佳,T_(500)从14 s降低到5 s,J环的障碍高差BJ值从30 mm降低到17 mm。水泥净浆黏度试验及混凝土工作性试验结果表明,微珠的作用机理是通过降低混凝土黏度从而降低T_(500)的值,但微珠会提高混凝土的屈服应力,不利于混凝土扩展度的提高,因而本文对CRTSⅢ型板自密实混凝土的配制及选材具有理论指导的意义。

Effect of microbeads on performance of self-compacting concrete used in new slab tracks

This paper studies the mechanism of microbeads on the CRTS III self-compacting concrete using test methods including the concrete expansion,slump,T500,cement paste viscosity,etc.The results show that the proper amount of microbeads can significantly improve the workability of concrete.When the content of microbeads is 1.5%,the workability of concrete is the best,T500 decreases from 14 s to 5 s,and BJ decreases from 30 mm to 17 mm.The results of cement paste viscosity test and concrete workability test show that the action mechanism of microbeads is to reduce the value of the expansion time T500 by reducing the viscosity of concrete.However,microbeads can improve the yield stress of concrete,which is not conducive to the increase of concrete expansion.The research result has theoretically guiding significance for the preparation and material selection of CRTS III self-compacting concrete.