Caracterização de Argamassas à base de cimento Portland e cinza de casca de arroz oriunda da queima com e sem controle de temparatura

Abstract

Using the wastes as alternative materials has proved satisfactory according to some surveys. The Rice Husk Ash (RHA) is a plant residue that causes environmetal impact, being a meterial that has great potential to be used in the construction industry in the production of mortar and concrete by presenting high contente of sílica (SiO2) amorphous that can be used as pozzolan. The municipality of Alegrete/RS has as main economic activity the rice planting, which generates large amounts of waste volumes from rice husk ash, coming to own beneficiation process. In order to contribute for reducing this waste in the environment, this paper seeks to verify the feasibility of incorporating the Rice Husk Ash (RHA) as a partial replacement of cment in mortat production. RHA was used whit controlled burning, industrially produced by a company basedin town, and residual coming from a rice processing company in town, eithout any burn controls. The characterization of the RHA was performed by testing loss on ignition test, laser granulometric analysis, X-ray, diffraction analysis, X-ray fluorescence sprectrometry, density and pozzolanic activity index, according to NBR 12653/1922. To analyze the mortars in the fresh state, it were used consistency index and heat release curve of hydratation tests. For the hardened state of mortars were performed tests like compressive strenth, Mercury intrusion porosimetry, absorption, voids and scanning eléctron microscopy. To prepare the samples, the ratio of 1:3 was adopted as a reference: the water/binder of 0.21 by replacing cement in proportions of 10%, 15% and 20% for 2 types or RHA and 1 type of sílica. The results obtained were satisfactory in the mechanical performance of mortars, concluding that the use or RHA for this application is technically feasible, also contributing to provide a less final destination to the waste in the environment.