Study of water treatment sludge incorporation into interlocking concrete pavers

ABSTRACT The sludge generated in the water treatment plants is the result of several operations that aim the adequacy of water to the legal standards of potability. Although there are alternatives for water treatment sludge, the usual final disposal solutions, as direct discharge into watercourses, still represent large impacts and overload the systems involved. The present paper aims to evaluate the technical viability of the incorporation of sludge from water treatment plants into interlocking concrete pavers. The influence of sludge moisture on the concrete behavior was also evaluated. Interlocking concrete pavers with cement mass contents of 2.5%, 5.0% and 7.5% of sludge at its natural moisture and 5.0% of dried sludge were evaluated by tests of compression strength, tensile strength by flexion, voids index, water absorption and density. The results showed that contents of up to 5.0% of addition do not generate significant changes in the properties of the concrete. Therefore, it would be possible to add sludge from water treatment plants in on interlocking concrete pavers, since limited to low levels. The incorporation of industrial waste into building materials is a viable alternative to minimize the environmental liabilities resulting from processes of production and treatment of other materials.