Analysis Of Mechanical Properties Of High Temperature Basalt Fiber Reinforced Concrete Under Load

High-performance concrete is widely used in national defense projects and civil buildings.However,with the frequent occurrence of fires,explosions and other safety accidents,the mechanical properties of concrete have seriously deteriorated,posing a serious threat to people’s property safety.Researchers It is found that adding fibers to concrete can effectively improve its mechanical properties,but it has not systematically analyzed and simulated the change law of concrete strength under different fire conditions.At the same time,its strength change mechanism is not deep enough,and the study of constitutive equations is not enough.thorough.Therefore,this article simulates the changing trend of strength of basalt fiber concrete compared with plain concrete after building fires and explosions.At the same time,it simulates fire and rescue using natural cooling and water cooling,and comprehensively and systematically studies the changes in concrete strength.Trend to provide theoretical and data support for safety assessment of buildings after fire.In this paper,the following researches have been done through high-temperature dynamic and static experiments of high-performance plain concrete and basalt fiber concrete(1)By heating high-performance plain concrete and basalt fiber concrete,analyze the changes in the basic mechanical properties of the concrete after heating(the effect of high temperature on the quality loss of high-performance plain concrete and basalt fiber concrete,and the effect of high temperature on the wave velocity of concrete),and Analyze the difference of the basic physical properties of high-performance plain concrete and basalt fiber concrete with temperature changes.(2)Conduct static compressive experiments on high-temperature high-performance plain concrete and basalt fiber concrete,and use two cooling methods,natural cooling and water cooling,to analyze the compressive strength and peak strain of concrete under static load with temperature.Compare and analyze the change mechanism of concrete static compressive strength after adding basalt fiber to concrete,and compare and analyze the effect of high-temperature concrete on the static compressive strength of concrete under different cooling methods.(3)Based on the HSPB laboratory,the dynamic compression test of high-performance plain concrete and basalt fiber concrete was carried out,and three different loading speeds of 5.8m/s,7.8m/s and 9.8m/s were used to obtain different results.The effect of loading speed on the dynamic compressive strength,peak strain and strain rate of high-performance plain concrete and basalt fiber concrete.Analyze and discuss the mechanism of high temperature on concrete,the changes in dynamic mechanical properties of concrete after adding basalt fiber,based on two cooling methods of water cooling and natural cooling,and discuss the influence of different cooling methods on the dynamic mechanics of concrete.(4)Using SEM electron microscope scanning and XRD mineral analysis to analyze the internal microstructure of high-performance plain concrete and basalt fiber coagulation,analyze the change of concrete strength with temperature from a microscopic point of view,and combine the microscopic and macroscopic,systematic analysis of concrete The intensity changes due to temperature changes.(5)Under the same temperature,the same cooling method,and the same loading rate,the static compressive strength and dynamic compressive strength of basalt fiber concrete are greater than that of high-performance plain concrete.The addition of basalt fiber to concrete can effectively improve the compressive strength of concrete.(6)The compressive strength of high-temperature basalt fiber concrete and high-performance plain concrete after water cooling at the same temperature and the same loading rate is less than the compressive strength of concrete under natural cooling.Water cooling has obvious damage effect on high temperature concrete.