Abstract

The present study evaluates the influence of the replacement of natural sand for different contents of water treatment sludge (in wet and calcined conditions) on the performance of the concrete considering macro and micro scale analyses. Mixtures substituting 5, 7, and 10% of wet sludge (WS) and 5, 10, and 20% of calcined sludge (CS) were produced. For the macro scale analyses, the specimens were tested by water absorption, compressive and tensile strength, and modulus of elasticity. Carbonation, leaching, microtomography 3D, and SEM were carried out for the micro-scale analyses. From the results obtained, it can be observed that the WS significantly reduces the strength of concrete, not being indicated for applications in structural concrete. The replacement of up to 20% of sand with CS. In addition to increasing the compressive strength of the concrete, increased porosity, water absorption, and carbonation depth requires attention to durability aspects for using this residue in the production of structural and non-structural concretes. Using wastewater treatment sludge can contribute to circularity in the construction industry in line with sustainable development goals. Graphical Abstract: (Figure presented.)