Properties of sustainable concrete containing demolished concrete and tile waste powders.

This study investigates the combined use of concrete demolished waste powder (CDWP) and tile waste powder (TWP) as partial replacements for cement (0 to 15%) and fine aggregate (0 to 30%) in concrete. The concrete fresh properties, hardened properties and microstructural analysis were evaluated. Results show that CDWP and TWP reduce workability due to their rough and angular nature. The optimum replacement levels (5% CDWP and 10% TWP) improve fresh density and enhance mechanical strength through pozzolanic activity and improved interfacial transition zone (ITZ). However, higher replacement levels adversely affect workability and microstructure which leads to reduced strength. A strong correlations were observed between fresh properties and hardened properties. Furthermore, the SEM analysis confirms that improved microstructure is observed at lower replacement levels (5% CDWP and 10% TWP) and weak microstructure at higher levels.