Experimental Study On Material Properties Of Manufactured-sand Concrete In Seasonally Frozen Region

Nowadays the natural sand are relatively scarce resources,the use of manufactured-sand instead of natural sand as a fine aggregate in concrete will become a trend in the future.In this paper,the optimum proportion and durability of C30,C40 and C50 manufactured-sand concrete for bridges are studied.At the same time,the working performance,mechanical property and durability of concrete for cement pavement are tested.For C30,C40 and C50 manufactured-sand concrete for bridges,this article confirmed the optimum proportion that conform the requirement of working performance and strength for pump concrete by using an orthogonal test method that study the influence of water and cementitious material ratio,dosage of cementitious materials,fly ash content and sand coarse aggregate ratio for working performance and compressive strength of manufactured-sand concrete,and tests the frost resistance and impermeability of the manufactured-sand concrete formulated with the optimum proportion,and compare with the river sand concrete formulated with the same mixing ratio.The test results show that the frost resistance and impermeability of the manufactured-sand concrete are higher than the river sand concrete.For the flexural 5.0 concrete for cement pavement,this paper studied the influence of the substitution rate of manufactured-sand,water and cementitious material ratio and fly ash content for working performance,mechanical property and durability of concrete.It was found that the concrete slump gradually decreases,the compressive strength and the flexural strength gradually increase,and the wear resistance increases with the increase of the replacement rate of the manufacturedsand.As the water and cementitious material ratio increases,the concrete slump and working performance increase,the compressive strength,flexural strength and wear resistance gradually decrease.With the increase of fly ash content,the concrete slump increases gradually,but the influence of compressive strength,flexural strength and wear resistance is not obvious.Under the same mixing ratio,the frost resistance and impermeability of the manufactured-sand concrete are better than the river sand concrete.