Study On Performance Of Salt Erosionfor The High Strength And Hybrid Fiber Reinforced Self-compacting Concrete

This paper mainly studies the C60 high strength fiber reinforced self-compacting concrete sulfate corrosion. Three kinds of sodium sulfate solution concentration are 5%、10% 、 15%, selecting the long-term immersion test method studies the change of the compressive strength and splitting tensile strength of the ordinary high-strength self-compacting concrete without the fiber,the polypropylene fiber’s content of 0.06%、0.09%、0.15%,the basalt fiber’s content of 0.05%、0.10%、0.12% seven groups which are firstly placed in clear water after standard curing 28 days, then respectively in three different corrosion solution concentration of 30 days、60 days、90 days、120days.The test calculates the compressive corrosion coefficient K value, and selects the K value as evaluation standard. By the electron microscope test analyzes the self-compacting concrete’s microscopic structure after corrosion, from two aspects of macroscopic and microscopic complete the research on the properties of self-compacting concrete sulfate corrosion. This paper mainly completes the following studies:(1) The mixed fiber effectively improves the mechanical properties of self-compacting concrete. These two kinds fiber on the compressive strength of high strength self-compacting concrete improvement effect are all more significant; Basalt fiber’s effect on the improvement of the splitting tensile strength is more significant than polypropylene fiber; Dosage of the polypropylene fiber PF3 group(content 0.15%), basalt fiber BF3 group(content 0.12%) increase the compressive strength most obviously.(2) The mixed fiber has played an important role in enhancing and toughening the high strength self-compacting concrete. In the concrete specimen damage, the damage form of fiber high-strength self-compacting concrete has certain ductility comparing with the unmixed with fiber high-strength self-compacting concrete damage form, fiber mixed in a certain extent, improves the brittle failure of high-strength self-compacting concrete.(3) The mixed fiber effectively improves the sulfate corrosion of high strength self-compacting concrete. Different fiber content and solution concentration have different impacts on the sulfate corrosion of the high-strength self-compacting concrete, polypropylene fiber PF2, basalt fiber BF2 group in 10% solution improve the compressive strength most obviously; Polypropylene fiber PF3, basalt fiber BF3 group in 5% solution of corrosion improve the tensile strength most obviously; The stress corrosion coefficient K value of the fiber high-strength self-compacting concrete is higher, the resistance to sulfate corrosion performance is better.(4) By electron microscopy test observes the structure of the high strength self-compacting concrete specimen, finding that the mixed fiber can make the internal structure of concrete more closely, and delay the crack development; Observing the specimen eroded by sodium sulfate solution finds that specimens in 5% solution corrosion, 30 days internal corrosion has a small amount of ettringite, corrosion exist within 120 days has pores; By 10% solution corrosion specimens, there is a lot of internal needle and columnar AFt, and the expansion of internal force generated by the ettringite formation is the main reason of the destruction of the concrete.