Resumo:
Self-compacting concrete, SCC, is practically a new concrete that has peculiar characteristics
of fluidity and viscosity. To acquire such properties, it uses in its composition, mineral
additions, fine materials, which, in large part, are industrial waste and, therefore, a sustainable
material. Although the use of waste foundry sand (WFS) in concrete is already widespread,
there is a gap regarding the waste foundry exhaust sand (WFES) and its influence on the
reinforcement and, thus, producing a concrete that meets the prerogatives of compressive
strength, durability, longer useful life and sustainability. In this research, the marble and granite
processing waste residue, MGPW, was used as a mineral addition to improve the mixture
viscosity, and waste foundry exhaust sand (WFES) as a partial substitute (10%, 20%, 30%, 40
% and 50%) of natural sand. Foundry Exhaust Sand makes up the WFSs, which correspond, on
average, to 80% of the waste generated in the foundry industry. The influence of materials on
concrete rheology, strength and durability was evaluated. Rheological parameters were tested
by empirical methods. Mechanical properties were evaluated by compressive strength and
splitting tensile strength. As indicators of durability, the tests of water absorption by immersion
and capillarity, resistance to sulfates and acids attacks, bulk electrical resistivity, chloride
permeability and corrosion potential were used. In fresh state, all mixtures presented fluidity
and viscosity characteristics required by brazilian standard for SCC. As for compressive
strength, all mixtures were classified as high strength. Mixtures showed good resistance to acid
and sulphate attacks, low absorption by immersion in water and by capillarity. Very low
permeability to chloride ions and high electrical resistivity, indicates the mixtures showed a
negligible probability of corrosion and in the corrosion potential test the probability varied
between uncertain and low. These results indicated that SCC with MGPW and FES has lower
permeability to harmful agents and, consequently, greater durability when compared to
reference concrete. All properties were improved with 30% of FES waste, although good results
were obtained with up to 40%. In this sense, the use of these waste brings environmental
benefits that translate into both the reduction of waste deposited in landfills and the reduction
in the extraction of natural sand. the results show that the wastes, WFES and MGPW, can be
used without affecting the concrete durability.
