Estudo comparativo do potencial pozolanico de adições argilo-minerais disponíveis no amazonas e porto velho, utilizando as técnicas de termogravimetria, difração de raios-x e teste de cal saturada

Abstract

One of the proposals to reduce impacts to the environment is the use of renewable resources in addition to recycling of materials, reuse and recovery of waste. These measures entail the controlled use of raw materials in the production process of the industries, and reuse of final disposal materials that may be included again in the production chain, mainly in the civil construction sector. The use of residues and by-products, materials rich in aluminum and silicon with pozzolanic potential, by partially replacing cement enhance the properties of the cement material and can contribute to the preservation of natural resources as well as reduce energy consumption and control gas emissions pollutant. In this way, the present research proposes a comparative analysis of five different mineral additions in some regions of Amazonia, in Amazonas and Rondônia: there are four types of calcined clays, and the sludge ash of a water treatment plant (ETA) to characterize them for pozzolanic reactivity. A proposal to monitor hydration reactions by partial substitution in cement paste with 40% and 50% substitution rates of metacaulinite (ceramic and metacaulinite) and sludge ash in the mass of cement, with the presence of chemical additives to act in workability. The methodology of physical and chemical characterization made use of laser granulometry, X-ray fluorescence, X-ray diffraction, thermogravimetric analysis (TG / DTG) and saturated lime test. Reactivity was evaluated in the hydration process of the pozzolanic materials observing the effects of pozzolanic reactivity in relation to portlandite consumption at 28 days. All the materials studied showed pozzolanic potential, decreasing calcium hydroxide (CH), confirming that the 50% content of pozzolan from the burning of kaolin reduced the content of calcium hydroxide (Ca(OH)2) free in the cement matrix to approximately zero. 28 days. In the saturated lime test there was confirmation of the pozzolanic activity by the mineral additions in the reduction of Ca (OH)2, with percentages of reduction from 73% to 98% in 1 day of analysis, at 7 days the CH reductions reached 88% and at 28 days the pozzolans remained reactive with reduction between 30% and 65%, the metakaolin and ash of the ETA sludge showed to be more reactive with respect to the ceramic residues, corroborating with TG / DTG analyzes, but RC1 in 1 day of analysis had percentage of reduction of 98% same percentage of metacaulim.