Experimental Study On Mechanical Property And Durability Of Alkali-resistant Chopped Basalt Fiber Reinforced Concrete

Basalt fiber is a natural inorganic fiber with excellent mechanical properties,low price,and natural compatibility with germanium.At present,the application of basalt fiber to cement-based materials has become a research hotspot,but the alkali resistance problem of basalt fiber has become a controversial topic.Studying the alkali resistance of basalt fiber and its influence on the mechanics and durability of concrete has great significance for promoting the application of this fiber in concrete engineering.Firstly,this article studied the alkali resistance of fibers.This paper simulates the hydration and alkaline environment of concrete,and ordinary basalt fiber(BF)and alkali-resistant basalt fiber(ABF)are immersed in 20°C and 1 mol / L NaOH solution for 28 days respectively to measure the mass loss rate and mechanical properties at each age.It is concluded that after 28 days,the mass loss rate of BF is as high as 25.4%,while that of ABF is only 7.2%.The strong retention rate of BF is only 63.0%,while that of ABF is still 95.1%.The elongation rate of BF is stable at 1.99%,while that of ABF is stable at 2.83%.Secondly,this paper studies the influence of BF and ABF on the mechanical properties of concrete,and based on the optimal content of ABF,optimizes the mix ratio by adding fly ash.The influence of ABF and polyvinyl alcohol fiber(PVAF)on the mechanical properties of concrete was studied based on the optimal amount of fly ash.The results show that the mechanical properties of concrete mixed with BF decrease,while the incorporation of ABF significantly increases the strength of concrete.ABF,the best dosage of which is 0.1%,makes the compressive,flexural,and tensile strengths of concrete for 28 days increase by 2.5%,17.2%,and 12.1%,respectively.The best amount of fly ash is 15%.When the blend ratio of ABF and PVA fiber is 1:1,the hybrid fiber has the best effect on improving the mechanical properties of concrete.Finally,the influence of BF,ABF and the hybrid fiber of ABF and PVAF on the durability of concrete was studied.The result is that BF significantly reduces the durability of the concrete,while ABF significantly improves the durability of the concrete.Compared with single-doped ABF,the hybrid fiber blended with PVAF and ABF can further improve the durability of concrete.Both Concrete with fly ash and ABF(ABFRC-F)and concrete with fly ash and hybrid fibers(ABFRC-FH)have good durability and are suitable for harsh environments.