再生混凝土动态冲击性能

Dynamic Impact Properties of Recycled Aggregate Concrete

再生混凝土技术实现了建筑资源循环和建筑垃圾治理难的问题。目前再生混凝土在框架节点抗震、装配式建筑、钢混结构等方面应用较为广泛,然而在防护工程方面的研究相对较少。在现有再生混凝土SHPB(split Hopkinson pressure bar)试验基础上,采用动力有限元软件LS-DYNA对再生混凝土的冲击压缩性能进行了数值模拟研究,选用HJC(Holmquist-Johnson-Cook)模型作为再生混凝土的本构模型,根据试验结果标定了本构模型参数,在此基础上进行了拓展工况研究,并建立了再生混凝土动态增加因子(dynamic increase factor,DIF)计算模型。研究结果表明:HJC模型能够较为准确地模拟再生混凝土在高应变率下的动态压缩力学性能;欧洲混凝土委员会推荐的DIF计算模型不适用于再生混凝土,本文建立了新的DIF计算模型;应变率为71.7 s^(-1)时,试件开始出现轻微损伤,应变率达到200 s^(-1)后,试件呈现粉碎性破坏。

Recycled aggregate concrete technology solves the problems of building resource recycling and construction waste management.At present,recycled aggregate concrete is widely used in frame joint seismic resistance,prefabricated buildings,steel-concrete structures and so on,but there are relatively few researches on protection engineering.Based on the existing split Hopkinson pressure bar(SHPB)test results of recycled aggregate concrete,the dynamic finite element software LS-DYNA was uses to carry out a numerical simulation study on the impact compression performance of recycled aggregate concrete.The Holmquist-Johnson-Cook(HJC)model was selected as the constitutive model of concrete materials.The parameters of the constitutive model were calibrated by the test results.Based on this,the working condition expansion study was carried out,and the dynamic increase factor(DIF)calculation model of recycled concrete was established.The research results show these as follows.HJC model can more accurately simulate the dynamic compression mechanical properties of recycled aggregate concrete under high strain rate.The DIF calculation model recommended by European Concrete Council is not suitable for recycled concrete.Thus,a new DIF calculation model was established.When the strain rate is 71.7 s^(-1),the specimen began to show slight damage,and when the strain rate reached 200 s^(-1),the specimen showed crushing failure.