活性粉末混凝土冲击压缩性能及本构关系

Dynamic compressive properties and constitutive model of reactive powder concrete

为了克服传统活性粉末混凝土(RPC)须高温蒸养的缺点,采用粒化高炉矿渣代替部分水泥制备出免蒸养RPC,利用直径为80 mm的霍普金森压杆试验系统(SHPB)对免蒸养RPC进行冲击压缩试验研究,探究率效应对免蒸养RPC动态力学性能的影响规律,建立动态本构模型.结果表明:在10~290s^(-1)的应变率范围内,免蒸养RPC的峰值应力、峰值应变和冲击韧性表现出明显的率敏感性,而弹性模量在不同应变率下基本保持不变.改进型ZW-T黏弹性本构模型和基于Weibull分布的模型均能对免蒸养RPC的动态应力-应变曲线进行较好的描述,基于Weibull分布的模型所含参数相对较少,根据模型中各参数与应变率之间的关系可以对不同应变率下的应力-应变曲线进行预测.

The granulated blast furnace slag was used to replace part of cement to prepare steam free reactive powder concrete(RPC),in order to overcome the disadvantage of traditional reactive powder concrete(RPC)that needs high temperature steam curing.The impact compression experiment of steam free RPC was carried out by using split Hopkinson pressure bar system(SHPB)with diameter of 80 mm,the influence of rate effect on the dynamic mechanical properties of steam free RPC was explored at the same time,and the dynamic constitutive model was established based on the experimental results.Results show that in the strain rate range of 10~290s^(-1),the peak stress,the peak strain and the impact toughness of the steam free RPC show obvious rate sensitivity,while the elastic modulus remains unchanged under different strain rates.On the aspect of constitutive model,both the improved ZW-T viscoelastic constitutive model and the Weibull distribution-based model can well describe the dynamic stressstrain curve of steam free RPC.Due to the relatively fewer parameters Weibull distribution-based model contains,the stress-strain curve under different strain rates can be predicted based on the known relationship between parameters and strain rate in the model.