Effect of limestone powder on mechanical properties and microstructure of phosphogypsum

Abstract

In order to enhance the large-scale and high-quality application of limestone powder (LP) and phosphogypsum in the construction industry. Therefore, this paper mainly studies the effect of LP on the physical and mechanical properties of phosphogypsum-based composites, and clear the mechanism of action from the micro level. Based on the results, the conclusions were as follows: LP has the effect of reducing the standard consistency water requirement and shortening the setting time of fresh phosphogypsum-based composites slurry; LP can increase the bulk density and reduce 24-hour water absorption of hardened phosphogypsum-based composites matrix; In addition, the strength of the matrix increases first and then decreases with the increase in the amount of LP and the recommended amount of LP is 5%-10%. Microscopic tests have shown that when the amount of LP is less than 10%, it can effectively reduce the porosity, refine the pore size, and play the role of a dense hardened matrix. In addition, the appropriate amount of LP particles can be adsorbed on the surface of dihydrate crystals, increasing the bonding force between the crystals, which is conducive to increasing the strength of the composite matrix.