Experimental Study On Sulfate Resistance Of Polypropylene Fiber Fly Ash Concrete

Sulfate attack lowers the strength of concrete,It is easy to cause concrete structure failure.The amount of cement can be reduced by adding proper amount of fly ash in concrete,mechanical strength of reinforced concrete,improving the sulfate resistance of concrete.The amount of polypropylene fiber is 1kg/m3,the content of fly ash is 0,15%and 30%respectively;the erosion states were soaked by natural soaking and wet drying cycles;the basic mechanical properties of polypropylene fiber concrete were 1 month,2 months,3 months,4 months,and 5 months respectively and the time of sulfate attack is mass loss and strength loss at 1d,14d and 28d respectively.The results of the basic mechanical tests under different corrosion states show that the strength of the polypropylene fiber reinforced concrete with sulfate attack is generally decreasing.When the content of fly ash is 15%,in the natural immersion corrosion of sulfate,the strength of polypropylene fiber concrete corroded for 1 month,2 months,3 months,4 months and 5 months was reduced by 2.3%?3.2%?19.4%?13.8%and 25.6%,respectively,compared with that of fly ash concrete;In dry and wet cycles,the specimens decreased by 6.91%?1.50%?2.40%?5.26%and 6.01%,respectively,compared with those without fly ash.The test results are also shown,when the content of fly ash is 15%,the strength of concrete is the largest,that is,the resistance to sulfate attack is the best.Quality and strength loss test results show that,the quality and tensile strength of polypropylene fiber reinforced concrete specimens showed a downward trend,the overall quality of the concrete specimens decreases gradually after erosion,the strength decreases and the durability decreases.When the content of fly ash is 15%,the mass of polypropylene fiber concrete specimens subjected to sulfate attack at 1d,14d and 28d are 2.8655kg?2.38275kg?2.37950kg,respectively,the compressive strength is 60.3MPa?55.7MPa?55.4MPa,the splitting tensile strength is 4.27MPa?3.94MPa and 3.83MPa,respectively,compared with fly ash,the concrete specimens with 0 and 30%content are more strength.Adding fly ash into concrete structure not only increases the strength of the specimen,resistance to sulfate attack will also be enhanced and its durability will be met,energy conservation and environmental protection,provide test data for engineering application.