Use of concrete sludge waste as substitute of hydrated lime for production of rendering mortars

Abstract

ABSTRACT: Civil construction has been recognized as an activity responsible for major environmental degradation. Therefore, greater sustainability in this sector of the economy can be improved by adopting “clean technologies” to minimize environmental impacts in terms of waste generation and energy and material consumption. Still little studied, the use of concrete sludge waste (CSW) as an alternative material for the production of mortars can be a viable alternative. The purpose of this study is to evaluate the mechanical performance of mortars produced with dry sludge as a total and partial substitute for hydrated lime, evaluating its behavior through tests of consistency, flexural strength and compression, water absorption by capillarity and density. In the fresh state, it was found that the use of CSW has a negative impact on the workability of mortars, especially for replacement rates above 75% by mass. On the other hand, the substitution of hydrated lime, up to 50% by mass, is feasible, presenting mechanical properties equivalent to the mix taken as reference.