Thermally Modified EPS Material And Its Lightweight Concrete Physical And Mechanical Properties

With the development of economy,the development of traditional concrete is gradually restricted.Expanded Polystyrene?EPS?is a light-weight polymer with light weight,heat insulation,sound insulation,shock resistance,water resistance,thermal insulation,and strong shock resistance.After recycling and modifying waste EPS,it is used as aggregate to prepare lightweight concrete,which not only reduces resource consumption,but also reduces its pollution to the environment.Based on this,this article selects four EPS materials with different densities?10kg/m³,15kg/m³,20kg/m³,25kg/m³?to carry out research in the following aspects:The EPS materials with different densities were thermally modified to test their changes in compressive strength,volume,and micro-morphology at different modification temperatures.The results show that as the temperature increases,the volume of EPS material gradually decreases,the strength gradually increases,and the microscopic pore size gradually decreases.The specific performance is that under different residence time conditions,for the same modification temperature and different density EPS materials,the modified volume shows a positive correlation with the density,that is,V_25K>V_20K>V_15K>V_10K;Among them,in the range of 110¹20?,the volume change rate is large,about 80%,after exceeding 120?,the volume change is within 5%;for EPS materials with a density of10K,125?is the maximum strength point.As the temperature continues to increase,the film-like micropores on the surface of the EPS material continue to melt.The pores with original pore walls<1?m and pore diameters of 60-120?m are thermally shrunk to 120°C.The small pores of 10-30?m,this honeycomb structure is an important reason for the improvement of mechanical properties of EPS materials after high temperature modification.Through orthogonal experiments,EPS modified concrete blocks with different volume fractions were prepared by using the thermally modified EPS as aggregate,and the compressive strength,water absorption and micro-morphology of the interface transition zone under different conditions were tested.The range analysis of the compressive strength test results shows that the primary and secondary relationship of the influencing factors of EPS concrete compressive strength is:temperature>volume fraction>density,that is,compared with density and volume fraction,temperature The effect of intensity is greatest,followed by volume fraction.Through analysis of variance of compressive strength,the results show that the modification temperature of EPS material has a more significant effect on strength,and the density of the material itself has little effect on strength.Through the test of its water absorption,it is found that for the EPS concrete of the same condition,the water absorption increases with the increase of the volume fraction.By testing the micro-morphology of the interface transition zone,the results show that as the density and processing temperature of the EPS material increase,the bonding performance of the EPS concrete interface transition zone is better.In summary,the EPS thermal modification method can significantly increase the compressive strength of concrete as lightweight aggregate,thereby achieving the purpose of lightweight and high strength.