Influence of Acidic and Alkaline Environments on the Mechanical Properties of Cement Mortars

Abstract

Cement-based materials are exposed to various internal and environmental aggressions of acidic and alkaline nature that may affect their durability. This study investigates the influence of aggressive environments on the mechanical and physical behavior of cement mortars. Mortar specimens (4 × 4 × 16 cm³) were prepared with a water-to-cement (w/c) ratio of 0.5 and cured in water at pH 7 for 28 days. Additional specimens were exposed to sulfuric acid solutions at pH 2, 3.5, and 5, as well as alkaline solutions at pH 11 and 12.5. The findings indicate that mortars deteriorate significantly when exposed to acid. Mass losses can reach 20%, compressive strength losses range from 31% to 47%, and tensile strength losses range from 16% to 34%, depending on the acidity. In contrast, alkaline exposure results in a little expansion, which can raise mass and volume by as much as 2.3%. Both the tensile and compressive strength losses remain below 11% and 16%, respectively. In order to clarify degradation mechanisms and guide the development of more resilient cement-based materials, this study compares the behavior of mortar in extremely acidic and alkaline environments.