Preparation and properties of alkali-activated cement containing phosphorous slag and fly ash

Abstract

Phosphorous slag is an industrial waste which potentially pollutes environments. The aim of the present work is to use phosphorous slag as a raw material to produce alkali-activated cement. The influence of mix proportion of phosphorous slag and fly ash, alkali content and modulus of water glass on the properties of alkali-activated phosphorous slag and fly ash cement (AA-PS-FA-C) was studied. The results show that AA-PS-FA-C with normal setting performance and desirable mechanical properties can be prepared using water glass as the activator. Changing the fly ash content in the range of 0 - 40 wt. % has only a small influence on the setting time of AA-PS-FA-C. The strengths significantly decrease when the fly ash content exceeds 30 wt. %. The carbonation resistance of AA-PS-FA-C is similar to that of ordinary Portland cement (OPC), while the frost resistance is much better. The hardened paste of AA-PS-FA-C is much more compact than OPC paste.