Utilization of artificial lightweight aggregate and unground rice husk ash as internal curing agents to modify performance of super-sulfated cement mortar

Abstract

This study attempts to utilize cold-bonded fly ash based artificial lightweight aggregate (ALWA) and retrieved unground rice husk ash (URHA) as internal curing (IC) agents for improving performance of typical super-sulfaed cement (SSC) mortar fabricated with ternary mixture of 85% slag, 10% gypsum, and only 5% blended Portland cement (PCB). The ALWA partially replacing fine aggregate (FA) at four values of 25, 50, 75, and 100 vol.% was used. For evaluating impact of using hybrid addition of IC agents on performances of SSC mortars, the ALWA amount after being optimized was partially replaced by URHA at four levels of 25, 50, 75, and 100 vol.%. Experimental results showed that, ALWA partially replacing FA up to 50 vol.% led to the SSC mortars with remarkably increased workability and uncompromised impacts on the strengths and durability. Addition of URHA partially replacing ALWA significantly improved the fresh properties and flexural strength but it negatively impacted the durability performances of the resultant SSC mortars in terms of increased water absorption, decreased UPV, and increased drying shrinkage.