Development of lime-pozzolan green binder: The influence of anhydrous gypsum and high ambient temperature curing

Abstract

This study aims to improve the physico-mechanical properties of slaked lime – fly ash (FA) – ceramic waste powder (CWP) pastes through the incorporation of anhydrous gypsum (G) supported by thermal curing. Initially, the lime- FA paste was prepared with a ratio of (30/70 wt) as a reference binder. The FA was partially replaced with 5–25% of CWP material. The substitution of FA by CWP up to 20% exhibited a slight enhancement in the compressive strength at early and later ages of hydration. Adding 10% G provided additional improvements in the compressive strength, capillary water absorption and microstructure; this is confirmed by the thermogravimetric (TGA) and scanning electron microscopy (SEM) analyses. The high ambient temperature curing at 50 ͦC was found to be remarkably useful for improving the compressive strength of the gypsum containing composites at early age. The developed composites showed high solar reflectivity values which recommend for green building rendering applications. Such a kind of binder material could be helpful in reducing the negative impact of traditional Portland cement (PC), decreasing the ceramic waste disposal and contributing to the energy saving approach in building sectors.