成型压力对200 MPa级活性粉末混凝土抗压强度和微观结构的影响

摘要

For exploring the variation of compressive strength of RPC in various molding pressures,effect of molding pressure,initial pressing time and curing conditions on compressive strength of RPC were studied.The porosity and microstructure of products were mea-sured by MIP and SEM.Results showed that,the density of gel binder and interface adhesion between binder and aggregates were signifi-cantly improved by extremely litter molding pressure,thus improving the compressive strength of RPC.It's appropriate for the improvement of compressive strength that the initial pressing time should be 1-2 hours before initial setting time.High temperature curing condition could significantly increase the compressive strength of RPC,but it would be weaken the enhancement effect by molding pressure on com-pressive strength of RPC.%为阐明不同成型压力下粉煤灰微珠活性粉末混凝土抗压强度的变化规律，分别研究了不同成型压力、起始施压时间及不同养护方式等对活性粉末混凝土抗压强度的影响，并采用压汞、SEM研究了产物的孔隙率和微观结构。结果表明：在RPC成型过程中施加微小压力能显著提高RPC凝胶产物密实度和基体-骨料界面黏结程度，进而大幅提高其抗压强度。起始施压时间宜为RPC初凝前1~2 h，过早或过晚施压均不利于RPC抗压强度的发展。高温养护可大幅提高RPC的抗压强度，但会削弱成型压力对RPC抗压强度的增强效果。