Experimental Study On Mechanical Properties Of Basalt Fiber Nano-concrete After High Temperature

Compared with traditional concrete,fiber nano-concrete has the characteristics of high pull strength,good crack resistance and strong toughness,and it is a new type of composite material,which can improve the refractability,low temperature resistance and durability of traditional concrete to a certain extent.This paper mainly studies the effects of basalt fiber doping,nano-SiO₂ doping and temperature changes on the cube pressure strength,cracking pull strength,axis pressure strength and fold strength of basalt fiber nano-concrete before and after high temperature,It provides a certain theoretical reference for the research and engineering application of basalt fiber nano-concrete in the future.The main elements of the study are as follows:（1）The effects of different basalt fiber doping and different nano-SiO₂ doping on the pressure resistance strength,cracking and pull strength,axis pressure strength and fold strength of basalt fiber nano-concrete cubes were studied.The study found that compounding the appropriate amount of basalt fiber and the appropriate amount of nano-SiO₂ had an effect on the aesthetic performance of basalt fiber nano-concrete.（2）In the high temperature test,with the increase of temperature,the cube pressure strength of each group of concrete increases first and then decreases,and the cube pressure strength of each group of concrete reaches its peak at 400℃,and then decreases gradually.The cracking resistance,shaft pressure resistance and folding strength are gradually decreased with the increase of temperature.（3）The addition of basalt fibers improved the mechanical characteristics of basalt fiber nano-concrete after high temperature,and the amount of basalt fiber at 0.1%increased relatively significantly for its cube pressure resistance,axis pressure resistance and folding strength,and when the temperature reached 800℃,the increase was 28.3%,17.2%and 17.2%,respectively.The amount of basalt fiber with a doping of 0.15%increased its cracking and pull strength by a relatively significant amount,when the temperature reached 800℃,the concrete without basalt fiber increased by 13.5%.（4）The addition of nano-SiO₂ improves the mechanical properties of basalt fiber nano-concrete after high temperature,when the nano-SiO₂ doping is 1.0%,the trend of cube pressure resistance,shaft pressure resistance and anti-fold strength after high temperature of basalt fiber nano-concrete is relatively obvious.Nano-SiO₂,which is 1.5%doped,is relatively good for increasing the cracking resistance of basalt fiber nano-concrete after high temperature,at 800℃,the concrete without nano-SiO₂ was increased by 16.2%.（5）The fitting curves of relative cube compressive strength,relative splitting tensile strength,relative axial compressive strength,relative flexural strength and temperature of each group of concrete are established,which can provide reference for further study of mechanical properties of basalt fiber nano concrete after high temperature.