含粗骨料超高性能混凝土力学性能研究

Study on Mechanical Properties of Ultra High Performance Concrete with Coarse Aggregate

针对超高性能混凝土(UHPC)胶凝材料用量大,前期成本高等问题,通过在UHPC体系中掺入粗骨料,用河砂代替石英砂,成功制备了具有优异力学性能的含粗骨料UHPC,并通过试验研究了粗骨料掺量以及钢纤维几何参数对含粗骨料UHPC力学性能的影响.结果表明:随着粗骨料掺量的增加(0~800kg/m3),UHPC抗压强度先增加后下降,静力受压弹性模量几乎呈线性增加;粗骨料掺量为0~400kg/m3时,UHPC抗弯拉强度和初裂强度变化较小,粗骨料掺量为400~800kg/m3时,UHPC抗弯拉强度和初裂强度明显下降;随着粗骨料掺量的增加(0~800kg/m3),UHPC弯拉荷载-挠度曲线变化明显,弯曲韧性明显下降,但均存在应变硬化过程;随着钢纤维长度增加,UHPC的抗压强度、抗弯拉强度以及弯曲韧性均增加,但是静力受压弹性模量和初裂强度变化较小.

flexural toughness decreased obviously,but a strain-hardening process was observed.With the length of steel fiber,the compressive strength,flexural strength and flexural but the static compression modulus and initial crack strength o fU H P C changed little.Abstract:Due to the problems of large amount of cementitious material and high cost of Ultra High Performance Concrete(U H PC)#the U H PC system was mixed with coarse aggregate and river sand instead of quartz sand,and the preparation of U H PC with coarse aggregate is successful resulting in excellent mechanical properties.Meanwhile,the effects of the coarse aggregate content and geometric parameters of the steel fiber on the mechanical properties of the U H PC with coarse aggregate were studied.The results showed that,with the increase of coarse aggregate content(0#800 kg/m3),the compressive strength of U H PC increased firstly and then decreased,the elastic modulus increased almost linearly.When the content of coarse aggregate was in 0#4 0 0 kg/m3,the flexural strength and initial crack strength of U H PC changed little,while when the content of coarse aggregate was 400#800 kg/m3,the flexural strength and initial crack strength of U H PC decreased obviously.With the increase of aggregate(0?800 kg/m3),the flexural load-deflection curve of U H PC was obviously changed,and the