Utilização de resíduos da construção civil para correção granulométrica do solo de Dourados-MS para a fabricação de tijolos de solo-cimento

Abstract

Soil-cement bricks result from the homogeneous mixture of soil, cement and water,compacted by pressing and cured in the shade. As described in NBR 10833:2012, the soil suitable for the manufacture of soil-cement bricks needs to be 100% passant in the 4.75 mm sieve and from 10 to 50% passing in the 0.075 mm sieve, that is, the soil must have a maximum of 50% fines (silt + clay). The soil of Dourados-MS does not have adequate granulometry for the manufacture of cement soil bricks, being necessary the granulometric correction of the same for this purpose. In view of the above, the objective of this work was to perform mixtures of soil and Civil Construction Residues (RCC), in different proportions to correct the granulometry of the soil of Dourados-MS and to use the mixtures of soil and RCC for the manufacture of soil-cement bricks and to evaluate which mixtures of soil and RCC provide specimens with resistance to compression and water absorption suitable for use. Through the algebraic process, to determine the granulometric correction of the soil, it was verified that it was necessary, at least, 47% of CCR in the mixture, by mass, of soil and RCC to perform the granulometric correction of the soil of Dourados-MS. For the particle size correction, three mixtures of soil and CCR were performed, with 50, 60 and 70% of CCR. For each soil and RCC mixture, 15 specimens of soil cement bricks were molded in a manual press, using the trace, in volume, of 1:8 (cement: soil mixture and RCC). After pressing, the specimens were stacked in a place with a flat surface and protected from solar radiation and wind incidence, covered with a black plastic tarp and moistened during the first seven days of curing. After 28 days of curing, ten specimens were randomly selected and submitted to dimensional analysis, simple compression and water absorption. The three mixtures of soil and RCC were adequate to correct the soil granulometry of Dourados-MS for the manufacture of cement soil bricks, however, only the specimens from the soil mixture with 50% of RCC presented compressive strength higher than 2 MPa, being the only one to meet the compressive strength required in NBR 8491:2012, already with regard to water absorption, all treatments presented water absorption of the order of 21%, and the aforementioned standard requires that the water absorption is less than 20%.