Numerical Simulation Analysis Of Impact Resistance Performance Of Rubber Concrete

As an environmentally-friendly green material,rubberised concrete,which has the characteristics of large deformation capacity,high damping,good energy dissipation and good crack resistance,has attracted extensive attention and research in the civil engineering discipline.However,due to the addition of rubber crumbs,the strength and modulus of the concrete decrease significantly,which hinders the extensive application of this material in practical engineering.Therefore,here are relatively few researches on the dynamic compression performance of rubberised concrete,especially the dynamic strength of rubberised concrete under high strain rates.At the same time,the feasibility of rubberised concrete in practical structure is still lack of corresponding research.Currently,the applications of rubberised concrete are mainly limited to the non-load bearing structures and structural components,such as playground pavements,tracks,road pavements and non-load bearing partition walls,etc.Owing to the characteristics of good deformation,low modulus and good energy absorption capacities,research efforts have been devoted to investigating the possibility of using rubberised concrete to construct high-way road barriers.However,it is a general lack of understandings of the dynamic material properties of rubberised concrete and the impact resistance of rubberised concrete structures.Therefore,for better design of rubberised concrete barrier to resist vehicle impact,it is deemed necessary to research on the dynamic material properties and impact performance of rubberised concrete.This paper adopts numerical simulation method to systematically investigate the dynamic material properties and impact resistance of rubberised concrete under high strain rate,which provided a basis for the application of rubberised concrete material in the field of antidetonation and impact resistance,including the following contents:A meso-scale model of rubberised concrete considering aggregates and rubber crumbs is established based on the available experimental results.The mechanical properties of rubberised concrete under different strain rates were studied by numerical simulation.The meso-scale model was verified against both quasi-static compressive testing data and Split Hopkinson Pressure Bar(SHPB)dynamic testing data.Using the verified numerical model,the dynamic properties of rubberised concrete with various rubber content(0% ? 30%)under different strain rates were studied.The results show that rubberised concrete is a strain rate sensitive material and the strain rate sensitivity of rubberised concrete increases with the increase of rubber crumb.Based on intensive numerical simulation data,empirical functions of DIFs are derived as a function of strain rate and rubber content to predict the dynamic strength of rubberised concrete.The research is then extended to predict rubberised concrete structures subjected to impact loads.Based on the current design specification of concrete rigid barriers and the requirements for the safety performance of barriers,rubberised concrete is applied to highway roadside barriers.The numerical models of two grades(A-grade and SS-grade)F-type normal concrete barriers and rubberised concrete barriers are established.By establishing the numerical model of vehicle—barriers collision,and comparing the rubberised concrete barriers with the normal concrete barriers,the redirective performance,containment performance and buffering performance of normal concrete barrier and rubberised concrete barrier are examined and compared,and the anti-collision and antiimpact effect of rubberised concrete barriers is discussed,which provides relevant basis and new ideas for the feasibility of rubberised concrete as roadside barriers.The results show that the rubberised concrete barrier could reduce the impact force,acceleration and the damage of the vehicle significantly,which indicate that compared with the normal concrete barriers,they can more effectively protect the drivers and passengers in the collision.The results demonstrate the great application potentials of this green material for constructing roadside barriers and structures.