Experimental Study On Dynamic Mechanical Properties Of PVA Fiber Rubber Concrete Under The Influence Of Multiple Factors

In recent years,the generation of a large amount of waste rubber has gradually enriched the research on rubber concrete,and the continuous updating and iteration of science and technology has also enabled more high-tech products to be applied to engineering construction.Metal fiber,inorganic nonmetal fiber,synthetic fiber or natural organic fiber are added into concrete as toughening materials in synergy with elastic rubber,which continuously improves the performance of concrete materials.At the same time,concrete is often affected by impact load,temperature load,environmental factors and other factors in engineering construction.Therefore,it is very important to evaluate the bearing capacity of building materials under the influence of multiple factors.In this paper,four factors and three levels of orthogonal test were designed with rubber particle size(a),rubber particle substitution rate(b),PVA fiber length(c)and PVA fiber content(d)as factors,in order to find the optimal proportion of PVA fiber rubber concrete in this test,and the concrete under this proportion was treated by high temperature and solution erosion,and three kinds of impact pressures were selected for SHPB impact test.The main research results are as follows:(1)the results of orthogonal test show that the optimum proportion of PVA fiber rubber concrete is A3B1C3D2,that is,the rubber particle size(a)is 3-6mm,the rubber particle substitution rate(b)is 5%,the PVA fiber length(c)is 18mm,and the PVA fiber content(d)is 1.2kg/m3.(2)By analyzing the dynamic mechanical properties,it can be seen that the dynamic mechanical properties of PVA fiber rubber concrete soaked in clear water,NaCl and Na2SO4 solution,with the increase of temperature and impact air pressure,show the trend of first decreasing,then increasing and decreasing respectively.However,the dynamic mechanical properties of specimens immersed in NaCl+Na2SO4 solution decrease with the increase of temperature and impact pressure.(3)By analyzing the dynamic mechanical properties,it can be seen that the dynamic mechanical properties of PVA fiber rubber concrete soaked in clear water,NaCl and Na2SO4 solution,with the increase of temperature and impact air pressure,show the trend of first decreasing,then increasing and decreasing respectively.However,the dynamic mechanical properties of specimens immersed in NaCl+Na2SO4 solution decrease with the increase of temperature and impact pressure.(4)Micro-analysis shows that salt solution erosion can increase the porosity of the specimen to a certain extent,which leads to PVA fibers and rubber particles being pulled out from the inside of the matrix,thus reducing its mechanical properties.On the other hand,Na2SO4 solution reacts with PVA fiber rubber concrete to produce calcium sulfate dihydrate,which can effectively delay the development of cracks in concrete matrix.However,under the action of NaCl+Na2SO4 composite solution,this reaction does not obviously enhance the mechanical properties.Figure[50];Table[27]reference[98]...