Feasibility studies of using harvested rainwater in concrete mixtures

This study investigates the mechanical performance of concrete mixed with harvested rainwater collected at the Civil Engineering Laboratory, Universiti Teknologi MARA (UiTM) Shah Alam. In consonance with practices towards sustainable construction and efficient utilisation of water resources, this study aims to assess the suitability of harvested rainwater as an alternative source of mixing water for concrete production. The objectives of this study are to determine the chemical properties of the harvested rainwater, to evaluate the effects of harvested rainwater on the mechanical properties of concrete and to determine the optimum harvested rainwater content for sustainable concrete mixing. The water quality testing was carried out through measurement of pH, total dissolved solids (TDS), sulphate, and chloride in accordance with BS EN 1008:2002. Three water sample mixes were prepared for the concrete mix: 100% tap-water, 100% rainwater, and 50% tap-water mixed with 50% rainwater. Grade M30 concrete was produced and tested for workability by a slump test and for mechanical properties by compressive and flexural strength tests at 7, 14, and 28 days of curing. On the basis of this study, it can be concluded that harvested rainwater is a potential, sustainable and dependable alternative source of water for concrete production, and its utilisation could contribute towards environmental protection and sustainable development of the Malaysian construction sector.