Analysis of the influence of mineral coal reject (MCR) in mixed mortars: addition and substitution to Portland cement

ABSTRACT

Due to the environmental problem related to the deposition of residues from the production of mineral coal in Brazil, the objective of this study was to use the residue of mineral coal in the production of mortar as a mineral addition and also as a substitute for Portland cement. For analysis of the physical-mechanical properties of mortars, 5x10 cm specimens were used. Starting from a mortar trace without addition of residue, called reference, to later be used the contents of 10 and 15% for addition, and 20 and 30% for substitution of Portland cement with mineral coal residue. The mortar samples underwent a curing process in a humid chamber and, at 28 days, density tests in the hardened state, water absorption by capillarity, compressive strength and X-ray diffractometry were performed. The results obtained indicated that the mineral coal waste increased the water absorption of mortar by 67% and 100% for the addition of 10 and 15% of coal, respectively. To replace 20 and 30%, the increases in absorption were 133% and 33%, respectively. The mechanical resistance, on the other hand, showed a reduction, for addition of 10 and 15%, of 33% and 42%, respectively. For the replacement of cement by 20 and 30%, a reduction in strength of 35% and 47% was observed.

Keywords
Coal waste; mineral coal; mortar; waste