关键词: 加压预湿;轻骨料混凝土;孔隙结构;抗冻性

Abstract: For reducing the engineering routine 1 h normal pressure pre-wet time, the 1.5 MPa pressure pre-wetting method was adopted and compared with the method of normal pressure pre-wetting.The difference of water absorption rate and pore structure between shale and fly ash and effect of different water absorption rate of fly ash and shale on the frost resistance of the HPP fiber lightweight aggregate concrete was studied under different way of pre-wetting.The research shows that, under 1.5 MPa and normal pressure,water absorption rate difference of shale is big,but fly ash is small.Internal pore of the shale is small and mostly closed,the total porosity is larger,connection to external of the fly ash pore is good.Frost resistance of shale lightweight aggregate concrete is better than that of the fly ash, frost resistance of HPP fiber lightweight aggregate concrete is remarkably well under normal pressure.Number of lightweight aggregate concrete frost resistance can reach more than 225 times under 1.5 MPa pressure.

Key words: pressurized pre-wetting;lightweight aggregate concrete;pore structure;frost resistance