Study on Portland Cement Pastes Containing Sanitary Ware Ceramic Wastes at Elevated Temperatures

Resistance of Portland cement pastes incorporated 20 wt. % sanitary ware ceramic nano-powder wastes to firing temperatures from 100 up to 600 ℃ was investigated. Results revealed that all physical and mechanical properties were improved and gradually enhanced with firing temperatures, but only up to 400 ℃, and then adversely affected with any further increase of firing temperatures than 400 ℃, i.e. water absorption and total porosity decreased, whereas bulk density was enhanced. Water absorption and total porosity were decreased by 10 and 4 %, respectively, while bulk density was increased by 2.25 %. Furthermore, flexural and compressive strengths were also improved and increased by 1.69 and 1.2 %, respectively. Fourier transform infrared spectra (FT-IR) showed the disappearance of free lime and ettringite on firing. Scanning electron microscopy (SEM) showed that the crystal phase growth of the formed hydration products as a result of both normal hydration and pozzolanic reactions at ambient temperature were developed and modified due to the temperature exposure. The hardened cement pastes can withstand and resist only up to 400 ℃.