Adição de Resíduo de Polimento de Pisos de Concreto em Matrizes Cimentícias

Abstract

In the present work, the cementitious matrices behavior incorporating concrete floor polishing waste (CPFW) was studied. The waste, that is initially generated as a sludge, was oven dried at 65ºC until mass constancy for subsequent physical-chemical characterization. For this study, an experimental program was adopted. Pastes and mortars incorporating 4%, 6%, 8%, 10% and 12% (in relation to cement mass) of CFPW were produced and tested. Pastes samples were used for thermogravimetric (TG), scanning electron microscope (SEM) and X-Ray diffraction (XRD) analysis. Mortars mixtures were characterized at fresh and hardened states by flow table, compression and splitting tests, and immersion water absorption. CFPW was also characterized in terms of its chemical composition and morphology, using X-Ray Fluorescence (XRF) technique, SEM and TG. XRF of CFPW powder indicated siliceous and aluminous materials low concentrations in sample, indicating no pozzolanic activity of the waste. High concentration of calcium oxide (41%) in the sample confirmed the occurrence of CFPW carbonation, due to the chemical reactions of the hydrated phases with CO2 in the atmosphere. SEM images identified calcite and aragonite presence in the pastes containing CFPW, which are calcium carbonate polymorphs. These compounds formation in the cementitious matrices contributes to the immersion water absorption reduction and improves the mechanical performance of mixtures, since they promote the pores filling (filler effect) and accelerate the hydration rates of cement compounds. XRD patterns showed that the CFPW incorporation in cementitious matrices induced the carboaluminates formation, as hemicarbonate.