Study On Properties Of Coal Gangue Coarse Aggregate Concrete

Coal gangue is the solid waste produced in the process of coal mining and washing.It is one sort of the industrial waste minerals,which possess both the heaviestemissions and the largest storage of industrial abandoned mineral each year in recent China.Its production and stacking pollutes the environment,occupies the land,causes disasters and brings about huge economic losses.Therefore,it is urgent to realize the recycling of coal gangue.At present,to produce concrete by coal gangue is an effective way to realize the reproduction of coal gangue.Through the method of combining the experiment and theoretical analysis,this paper studied the influence on the working performance,mechanical properties and durability by replacing the coarse aggregate in concrete with coal gangue,and got reasonable analyzation for the mechanism of action of coal gangue.1.Through the concrete performance test comes the conclusion that the slump and fluidity of concrete decreases with the increasing replacement rate of coal gangue.2.Through the concrete mechanical performance test comes the conclusion:(1)When the curing period is 7 days,the mechanical properties(compressive strength,splitting tensile strength and static elastic modulus)of coal gangue coarse aggregate concrete are similar to that of ordinary concrete,and the mechanical properties of partial coal gangue replacement rate concrete are better than that of ordinary concrete.(2)When the curing period is 28 days,the mechanical properties of the concrete decreases with the increasing replacement rate of coal gangue.When the water cement ratio is 0.40 and 0.45,the compressive strength of concrete is concentrated between 38.10MPa~49.30 MPa and 35.25MPa~42.70 MPa,the splitting tensile strength is concentrated between 2.90MPa~3.48 MPa and 2.67MPa~3.04 MPa,the static elastic modulus is concentrated between 3.05×104MPa~3.57×104MPa and3.04×104MPa~3.43×104MPa;(3)When the curing period is 60 days,the mechanical properties of the concrete decreases with the increasing replacement rate of coal gangue.When the water cement ratio is 0.40 and 0.45,the compressive strength of concrete is concentrated between 38.45MPa~54.90 MPa and 37.44MPa~48.94 MPa,the splitting tensile strength isconcentrated between 3.10 MPa~3.77 MPa and 2.70MPa~3.33 MPa,the static elastic modulus is concentrated between 3.15×104MPa~3.76×104MPa and 3.13×104MPa~3.66×104MPa.3.Through the durability test comes the conclusion that the impermeability and antifreeze performance of concrete decreases with the increasing replacement rate of coal gangue.When the water cement ratio is 0.40 and 0.45,the relative permeability coefficients of concrete are respectively concentrated between 1.41 × 10-7cm / h ~ 4.39 × 10-7cm / h and 2.01× 10-7cm / h~4.67 × 10-7cm / h;When the water cement ratio is 0.4 and 0.45,the freezing and thawing times of ordinary concrete are more than 300 times,and the coal gangue concrete replacement rate is at 20%,40% and 60%,80%,100%,its freezing and thawing times are concentrated between 200~250 times and 150~200 times.