Experimental Study On Preparation And Mechanical Properties Of Basalt-polypropylene Hybrid Fiber Concrete With High Durability

The South China Sea islands have high temperature,high humidity and high salinity marine environment that endanger the safety and durability of island building structures seriously.Therefore,as for the infrastructure construction in China's South Island,the most important issue it has to confront is how to develop building materials with high durability.Combined with the harsh marine environment of the South China Sea and the particularity of the lack of building materials,the high durability of concrete was regarded as the main goal.This paper prepared high durability concrete which are applicable for the extreme marine environment through the test and theoretical research,further on,it studied the physical-mechanical properties of concrete with high durability systematically.Through the orthogonal test,this paper researched how the admixture and basaltpolypropylene hybrid fibers affect their resistance to chloride ion permeability,compressive strength and construction performance of C30,C40 and C50 concrete.The effects of basalt fiber and polypropylene fiber on the mechanical properties of C30,C40 and C50 concrete were studied by changing the content of basalt fiber and polypropylene fiber.The result shows that the appropriate amount of mixed fiber can improve the compressive strength of concrete,the flexural strength and splitting strength better,but it has little effect on the elastic modulus.The enhancement effect of basalt fiber on the mechanical properties of concrete is better than poly Propylene fiber.Hydration characteristics of high concerte were studied by means of TG-DSC and XRD,whose results show that the incorporation of the admixture effectively reduces the Ca(OH)2 content in the concrete and promotes the degree of hydration of cement;The distribution of fibers in concrete was intuitively described and their impact on highdurability concrete were analyzed through scanning electron microscopy(SEM).The effect of fiber on the pore structure of high durability concrete was studied by mercury intrusion method,the results show that the addition of fiber can improve the pore size distribution of high durability concrete,an appropriate amount of mixed fiber content can improve the fractal dimension of pore volume of high durability concrete.