Experimental Study On Preparation And Mechanical Properties Of Copper Tailings Reactive Powder Concrete

Reactive Powder Concrete(RPC)has been widely concerned by scholars and engineers at home and abroad in recent years.It has good tensile and compression resistance,and has good flexural cracking resistance.It is a cement-based composite material with excellent comprehensive performance.Its material components include cement,quartz sand,silica fume,steel fiber,superplasticizer,etc.In this thesis,copper tailings,an industrial smelting waste slag,is used to replace the quartz sand component in RPC to prepare copper tailings RPC.The mechanical properties and influencing factors were studied,and the numerical simulation of copper tailings RPC highway anti-collision wall was carried out to reduce the wall thickness and improve its anti-collision performance.The main research contents are as follows :(1)Copper tailings RPC was prepared by replacing the quartz sand component in RPC with copper tailings.The effects of two curing systems of 75℃ and 90℃ high temperature steam curing on the strength of copper tailings RPC and ordinary RPC were studied.The results show that the three strength values of copper tailings RPC are higher than those of ordinary RPC.The high temperature curing can stimulate the pozzolanic activity inside the copper tailings.The three strengths of 90℃ high temperature steam curing are 3.7%,7% and11% higher than those of 75℃ high temperature steam curing,respectively,indicating the feasibility of copper tailings RPC preparation.(2)Through orthogonal test,the effects of water-binder ratio,silica fume content,copper tailings replacement sand content and steel fiber content on the fluidity and mechanical properties of copper tailings RPC were studied,and the best mix ratio was obtained.The results show that the most influential factor on the strength of copper tailings RPC is waterbinder ratio,and the effects of various factors on fluidity and mechanical properties are different.Based on the analysis results of fluidity and mechanical properties of copper slag RPC,the optimal mix ratio of copper slag RPC is obtained.(3)The effects of water-binder ratio,silica fume content,sand replacement amount of copper tailings and steel fiber content on the fluidity and mechanical properties of copper tailings RPC were studied by orthogonal test,and the optimum mix ratio was obtained.The results show that the most influential factor on the strength of copper tailings RPC is waterbinder ratio,and the effects of various factors on fluidity and mechanical properties are different.Based on the analysis results of fluidity and mechanical properties of copper tailings RPC,the optimal mix ratio of copper tailings RPC is cement : silica fume : copper tailings sand replacement : quartz powder : steel fiber : water-binder ratio = 1 : 0.25 :0.5 : 0.37 : 0.018 :0.2.(4)Optimize the design of the anti-collision wall wall,reduce its thickness,design simulation optimization scheme,analyze the best wall wall thickness through ABAQUS software,control the change of collision speed and collision angle,analyze the peak impact force,maximum dynamic displacement and wall damage of copper slag RPC anti-collision wall,and meet the strength requirements.The research shows that the copper slag RPC anticollision wall with 120 mm wall thickness has good impact resistance and saves concrete materials and reduces the preparation cost.