Experimental Studies to Investigate Efficacies of Granite Porphyry Powder as Homologous Manufactured Sand Substitute

Stone powder and others waste powder causes serious harm to the environment, society, ecosystem and human well-being, applying it to concrete is a path of green and effective. In this study, a series of tests was carried out on manufactured sand concrete with different granite porphyry powder contents. The results showed that when the stone powder content was lower than 8%, the cracking resistance, compressive strength, chloride ion permeability resistance, and sulfate attack resistance of the concrete were significantly improved with an increase in the stone powder content. Although the early shrinkage rate of the concrete also increased with the increase in the stone powder content, the increase rate was slow. At the microstructure level, an appropriate amount of stone powder exhibited the ?filling effect" and "nucleation effect," which were conducive to the improvement of the concrete mechanical properties and durability. However, with an in-crease in the stone powder content, the early shrinkage of the concrete increased sharply when the stone powder content exceeded 8%, and the crack resistance, compressive strength, and chloride ion permeability resistance of the concrete decreased. At this time, the stone powder had a "diversified effect" on the microstructure of the concrete, and the existence of a large amount of stone powder was not conducive to the development of certain properties of the concrete. It is feasible to prepare concrete by replacing manufactured sand with an appropriate amount of stone powder and others waste powder, which can not only improve the performance of concrete, but also save cost, energy, avoid manpower and material consumption in waste powder disposal. The research conclusion shows that the allowable value of the stone powder content can be appropriately increased according to the actual application in concrete, which is an efficient, green disposal path for stone powder and other waste powder.