THE HYDROCHLORIC ACID EFFECTS ON MODIFIED CEMENT WITH NEW COMBINATIONS BASED ON CALCINED DAM'S MUD AND NATURAL POZZOLAN

Reducing the amount of clinker in the cement industry using Supplementary Cementitious Materials (SCMs) is one of the solutions developed by researchers in our field to respect environmental requirements. In the same context, the present work aims to test the feasibility of new combinations using two Algerian SCMs and evaluate their behavior while exposed to hydrochloric acid. To concretize this objective, we fabricated a control mortar (based on cement CEMI) and nine other mortars containing modified cement by a binary and ternary mixtures of Portland Cement CEMI, Calcined Mud of Chorfa Dam, and Natural Pozzolans. All these mixtures were tested at fresh state for consistency and setting time of pastes and at hardened state for apparent density measure, water absorption, and compressive strength of mortars. After that, the ten of them were immersed in hydrochloric acid (HCl) 5% during fifteen weeks (105 days). Then they were examined for mass loss, volume loss, density decrease (apparent density), and visual appearance. The results obtained in most tests showed that the mixtures containing SCMs, especially the ternary mixtures, are realizable, economical, and more advantageous compared to the control mortar with higher water demand and a better behavior after compression and HCl attacks. In the end, we propose the mortars containing ternary mixtures with rates of 10% and 20% to develop new formulations with high performance.