Análise comparativa do potencial de utilização de resíduo de mineração em argamassa autonivelante.

Abstract

The mining sector is of paramount importance to Brazil, as it promotes job creation and economic growth in the country. On the other hand, it is one of the sectors that most pollute the environment, causing numerous problems in the social and environmental spheres. On the other hand, civil construction is one of the sectors that most consume natural resources and, for this reason, studies aiming at incorporating the tailings of the mining industry in construction materials have been expanding, as well as studies regarding the increase in productivity in construction sites, which is the case of self-levelling mortars, due to its high fluidity and capacity to model itself according to the substrate to which it will be laid. With this in mind, this work aims to study the effects of incorporating quartz powder mining residue into self-leveling mortars, partially replacing the fine aggregate in percentages of 15%, 30% and 50%, with curing ages of 7, 14 and 28 days. In order to carry out the study, the physical characterization of the sand, quartz and cement was first carried out through the tests of granulometry, specific and unitary mass and fineness modulus. Then, the traces and the percentage of the superplasticizer additive and viscosity modifier were defined, chosen from the bibliography study, and the mini-slump test was performed in the fresh state, thus obtaining the optimum mortar dosage. Subsequently, tests were carried out in the hardened state of resistance to compression, absorption and specific gravity. The results showed that the increase in the percentage of quartz powder was directly proportional to the compressive strength and inversely proportional to the water absorption, that is, the 50% replacement self-levelling mortar obtained greater compressive strength and consequently lower water absorption , when compared to the conventional one. According to the apparent density test in the hardened state, the higher the percentage of substitution, the heavier the mortar was, a fact explained by the difference in unit mass of sand and quartz powder, the residue being heavier than natural sand. Thus, according to NBR 13,281, the self-leveling mortar with 50% replacement of natural sand by the residue is classified as P6, that is, high-strength mortars and all were classified as M6, mortars greater than 1800 Kg / cm³.