Effect of High-Calcium Fly Ash on Activity Index and Hydration Process of Phosphorous Slag Powders

Effect of the dosage of high-calcium fly ash and fineness of phosphorous slag powders on activity index of phosphorous slag powders was explored. The hydration samples of phosphorous slag powders with high-calcium fly ash content were analyzed using XRD, DSC-TG and SEM. The results showed that activity index of phosphorous slag powders increased and then decreased with the dosage of high-calcium fly ash increasing. When the dosages of high-calcium fly ash were 15%-20%, activity indexes of phosphorous slag powders were above 1. With fineness of phosphorous slag powders increasing with ranges from 370 to 440 m2·kg-1, activity indexes of phosphorous slag powders increased with ranges from 1.028 to 1.174. High-calcium fly ash accelerated the hydration reaction of phosphorous slag powders, and promoted the increase in the strength of phosphorous slag powders glue-sand.