Adsorption Characteristics of Recycled Sand Derived from Waste Concrete
In order to solve the problem of rapid loss of concrete workability caused by high adsorption of recycled sand,six kinds of recycled sands of C20~C60 were used as objects.The pore structure characteristics of recycled sand were tested by mercury intrusion and low-temperature liquid nitrogen adsorption methods,and the physical composition of recycled sand was tested by X-ray diffraction(XRD).The adsorption law of recycled sand on water,methylene blue,and superplasticizer was explored.The results show that the water absorption rate of recycled sand decreases with the increase of strength grade of waste concrete materials,which is closely related to pore structure.The adsorption of recycled sand on methylene blue decreases with the decrease of clay mineral content,and there is no significant correlation with pore structure.The adsorption of recycled sand on superplasticizer is affected by both pore structure and clay mineral,but mainly depends on clay mineral content.