活性粉末混凝土抗压力学性能及指标取值

Compressive Mechanical Properties and Indexes of Reactive Powder Concrete

基于最紧密堆积原则进行活性粉末混凝土(RPC)配合比设计,对RPC在热水养护制度下的抗压强度和变形性能进行试验研究,建立了RPC立方体抗压强度计算模型.结果表明:RPC立方体试件沿加载端向下产生纵向裂缝,棱柱体试件的破坏形态包括剪切型和楔子型;RPC二次与首次抗压强度的比值约为0.80,轴心与立方体抗压强度的比值与普通混凝土基本相同;RPC抗压强度和弹性模量随着水胶比的增大而减小,随着钢纤维体积分数和硅灰掺量的增大而增大,所建立的强度计算模型准确性较好.将RPC划分为10个强度等级,确定了不同等级RPC的抗压强度平均值和变异系数,建立了轴心抗压强度、弹性模量和峰值应变的表达式,最终提出了不同强度等级RPC的抗压力学性能指标建议取值.

Mix proportion of reactive powder concrete(RPC)was designed according to densest packing principle.The compression strength and deformation performance of RPC specimens under hot water curing were experimentally analyzed,and the calculation model for RPC cube compressive strength was established.Test results show that longitudinal cracks beginning from the loading end appear on the cube specimens.Shear failure and wedge-shaped failure are shown for prism specimens.The ratio between secondary and primary cube compressive strength is 0.80,and the relation of axial and cube compressive strength is basically the same as that of conventional concrete.The compressive strength and elasticity modulus of RPC decrease with the increase of water-binder ratio,while they increase with the increase of the volume fraction of steel fiber and mass ratio of silicon powder.The established model has better accuracy for calculating the compressive strength and can be suggested for practical design.Furthermore,the cube compressive strength of RPC is classified into 10grades,and the mean value and variable coefficient of compressive strength for all grades have been obtained.The expressions of axial compressive strength,elasticity modulus and peak strain are then established,on which the compressive mechanical property indexes can be determined for different grades of concrete.