Reuse of stone slurry waste water in production of ready mix concrete

Abstract

This research investigates the effect of using wastewater from stone slurry waste on concrete properties. The variables of the research are, type of water (tab, stone slurry water, a-with flocculant, b- without flocculant), w/c ratio (0.5, 0.6 , 0.7) , type of tests (slump, compressive , flexural tensile, and absorption), curing time (7,14,28 days) and percent of wastewater replacement as substitute of tab water (30% and 100%). 27 concrete batches were prepared (over 240 samples were prepared). From each concrete batch the following samples were casted: 6 cubes for compressive test, 2 cubes for absorption test after 28 days, one beam (10 cm x 10 cm x 50 cm) for flexural tensile test after 28 days cuing. The experimental data were recorded as the average of two sample tests after each curing age. The test results revealed a decrease in slump of fresh concrete (workability) by using wastewater in substitute of tab water. The results showed that at w/c=0.7 the compressive strength of concrete after 28 day curing didn’t affected significantly at replacement ratio of 30% and 100%. However, at w/c of 0.5 and 0.6 a varying reduction of compressive strength were observed, at different ages and replacement ratios of stone slurry wastewater were observed. Analysis of the tests results showed that, at 20% replacement of tab water with stone slurry wastewater, the range of reduction in compressive strength is within the acceptable range of the ACI code for nontraditional mixing water. For reinforced concrete stone slurry wastewater may be used at w/c =0.7and replacement ratio(30% and 100%) for production of self-compacted concert , low grade concrete or plane concrete .