Assessing the Performance of Concrete Mixed with Different Water Sources within Small Scale Mining Catchment Areas in Ghana

Abstract

The performance of concrete samples mixed with different water sources, namely: tap water, river, borehole and hand-dug well from small scale mining catchment areas (known as “galamsey” in Ghana) was assessed. Concrete in the “galamsey” areas are being produced with these water sources contaminated by the mining activities. The objective of the study was to assess the performance of concrete mixed and cured with the different water sources. Parameters assessed included compressive and flexural strength, Sulphate attack and Scanning Electron Microscopy (SEM) Analysis. Concrete mixing and casting were in accordance with BS EN 12390-2:2019 while compressive and flexural strength tests were in conformity to BS EN 12390-3:2019 and BS EN 12390-5:2019 respectively. Water parameters tests were conducted in accordance with GS 175-1:2009. Sulphate attack test was conducted based on ASTM C1012:2018.  The results indicate that the compressive strength of concrete from all the water sources (river, hand-dug well and borehole) was about 90% and 70% of the control (tap water) specimens at the 28th and 180th days of curing respectively. It was noted that the concrete produced from the three water sources (borehole, hand-dug well and river) performed poorly against sulphate attack i.e. lost about 35%, 34% and 38% respectively of their compressive strength after 180 days of immersion in MgSO4 solution. Concrete mixed with the river and hand dug well water had lower alkalinity with pH values of 6.5 and 8 respectively. The morphological analyses at different magnifications showed deep and persistent cracks within the concrete mixed with the contaminated water. This study recommends that water from any of the water sources in the “galamsey” areas of Ghana should be treated before using for structural concrete and long term usage.