Durability of concrete containing gypsum powder recycled from waste drywalls combined with high content of fly ash as supplementary cementing materials

Abstract

To address the negative contribution of cement production on global carbon emissions, this study aims to reduce the cement content typically required in concrete using partial replacement by gypsum powder recycled from waste drywalls (15%) and fly ash (50%), by weight. The durability of concrete cylinders made of the mixture was evaluated by testing the cylinders in compression after exposure to various environmental conditions for 1000-, 3000- and 5000 hours. A total of 45 specimens under five exposure conditions were considered. The conditions included: dry, submerged in fresh water, submerged in seawater, and two groups rotated weekly between dry and submerged in either fresh water or seawater. Overall, specimens in both freshwater and seawater conditions after 5000 hrs showed strength higher than control specimens. Results indicate that the strength of the concrete specimens containing recycled gypsum powder and fly ash was not adversely affected by exposure to the conditions.