The effect of cement mortar composition on the pH value

Abstract

Cement-based materials (CBMs) initially start their life at a high pH of about 12.5- 13.5, which is further reduced due to several factors. These include ageing, penetration of moisture, carbonation, chloride ingress, alkali leaching, corrosion, and other biodegradation processes. A less reported factor enhancing the above reduction is incorporation of supplementary cementitious materials (SCMs) as partial replacement of cement due to the consumption of Ca(OH)2 in their pozzolanic reaction. In this study, pH and effect of Ca(OH)2 contents of cement mortars having 50% of fly ash and ground granulated ballast furnace slag were studied up to the age of 150 days. The results obtained strongly indicate that pH is not only dependent on the Ca(OH)2 content in cement mortars as specified in the most previous studies.