Use of water treatment sludge (WTS) as fine aggregate in concretes: evaluation of physical-mechanical properties

ABSTRACT The present work has an objective to investigate the use of water treatment plant sludge (WTS) as fine aggre-gate in concretes. Were evaluated the effects of different sand replacement levels (2.5%, 5%, 7.5% and 10% by mass) by WTS and the w/c ratio (0.4, 0.5 and 0.6) in physical (bulk density, porosity and water absorption by immersion) and mechanical properties (compressive and splitting tensile strength) at different ages (7, 28 and 91 days). All the collected data were statistically analyzed using analysis of variance (ANOVA). The results showed that, despite the minimization of the properties in comparison with the reference concrete, all concretes showed values of compressive strength greater than 25 MPa at 91 days considering the highest w/c ratio (0.60). Therefore, the WTS can be used in concretes, considering the properties analyzed. In this way, the present study shows that the WTS can be used as fine aggregate in concrete, being a valid and sustainable alternative for use in construction.