Industrial wastes as alternative mineral addition in Portland cement and as aggregate in coating mortars

Abstract

This paper presents an evaluation study of wastes from pulp and paper as well as construction and demolition industries for application in cement-based materials. The alternative raw materials were used as a source of calcium carbonate (CaCO3) and as pozzolanic material (water-reactive SiO2) in partial replacement of Portland cement. In addition to the hydraulic binder, coating mortars were composed by combining the pulp and paper fluidized bed sand residue with construction and demolition wastes, both added as small aggregates. Rheological and mechanical characterization showed that the waste additions changed the behavior of the cement materials, increasing both the viscosity of the pastes (at constant shear stress or rate). The formation of agglomerates in the cement hydration process made the mortars with additions of residues (lime and ash sludge) have an increase in the mechanical strength of the hardened bodies when compared to the mortar (M0W) prepared only with the residues (fluidized bed sand and C & D) as aggregates.