Experimental Study On Mechanical Properties And Durability Of Basalt Fiber Slag Powder Concrete

Due to the effects of chloride salt erosion,wet and dry alternation,sulfate attack,seawater scour and carbonization,some of the coastal concrete buildings have a phenomenon of concrete cracking and severe corrosion of steel bars,having a low durability.Improving the durability of concrete has great significance for the development of marine resources and the construction of offshore structures.This paper studies the effects of basalt fiber and slag powder to the mechanical properties and durability of concrete.Firstly,the optimum dosage range of slag powder and basalt fiber is determined by single factor experiment.Secondly,the optimal mix ratio of basalt fiber slag powder concrete is determined through orthogonal test,which regards the slag powder,basalt fiber and high performance water reducer as research object and regards the mechanical properties of concrete as evaluation indexes.Finally,the influence of basalt fiber and slag powder to the performance of the chlorine erosion resistance and anti-freezing of concrete is studied by electric flux test,artificial seawater erosion test,silver nitrate color test and rapid freeze-thaw test.The research results show that the optimum dosage of slag powder is 35%~55%,and the optimum dosage of basalt fiber is 0.1%~0.2%.The optimal mix ratio of basalt fiber slag powder concrete is determined,and that is,the proportion of slag powder is45%,the proportion of water reducer is 1.0%,and the volume proportion of basalt fiber is 0.20%.The electric flux of basalt fiber slag powder concrete is reduced by50.4% compared with ordinary concrete,and the penetration depth of chloride ion is reduced by 55%.When the freeze-thaw cycle is performed 300 times,the mass loss rate is 0.97%,and the relative dynamic elastic modulus is 82.3%.It is known from the test above that adding basalt fiber and slag powder to concrete can improve mechanical properties and durability significantly,and it also has certain guiding significance for the application of offshore concrete.