Estudo da influência da incorporação de resíduo de gesso nas características do tijolo solo-cimento

Abstract

This dissertation investigated the use of recycled gypsum waste as a partial replacement for cement in the production of soil-cement composites, focusing on the evaluation of physical-mechanical performance and the environmental feasibility of the proposed solution. The soil used was characterized in terms of particle size distribution, chemical composition, and consistency limits. Portland cement CP V-ARI was selected for its high early strength, suitable for the experimental schedule. Improper disposal of gypsum waste poses a growing environmental concern, particularly due to the potential release of sulfates into soil and water bodies. This study aimed to mitigate such impacts by reusing this waste in soil-cement formulations. The gypsum was dried, ground, and sieved prior to incorporation in varying proportions. The materials were characterized using XRF, XRD, FTIR, and SEM/EDS. Cylindrical specimens were molded with 0%, 10%, 20%, and 40% gypsum replacing cement, and were tested for compressive strength and water absorption after 7 and 28 days of curing. Composites with up to 20% gypsum showed compressive strength of up to 3.87 MPa at 28 days and water absorption below 18%, meeting performance requirements for non-structural applications. In contrast, the 40% gypsum formulation exhibited significant strength reduction and microstructural degradation, with excessive ettringite formation confirmed by XRD and SEM. These findings highlight the need for careful control of gypsum content to ensure composite stability. It is concluded that incorporating up to 20% recycled gypsum is a technically viable, environmentally strategic, and economically feasible solution, capable of converting an environmental liability into a sustainable input for civil construction.