POTENTIAL USE OF TROPICAL LANDFILL LEACHATE IN MANUFACTURING PORTLAND CEMENT CONCRETE

Abstract

Landfills are known sources of environmental contamination through the formation of leachate, which is a contaminated aqueous effluent produced when water percolates through the waste in landfills. Previous research has shown that landfills pose a direct threat to water resources and health in Trinidad and Tobago (T&T), and that there is the need to find efficient ways to manage landfill leachate. A recent study showed that landfill leachate was able to be used in the production of sand-lime products. As Portland Cement Concrete (PCC) is a common construction material used within the Caribbean, it is being proposed that tropical landfill leachate can be utilised in the making of concrete products. Treated (TL) and Untreated (UTL) tropical landfill leachate at 25%, 50%, 75% and 100% were used as a replacement of water in making concrete cubes. Compressive strength of those cubes was then measured against the controls at 3, 7, 14, 21 and 28 days. Cube samples were then analysed for hydrated products using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). The concrete cubes made with UTL produced similar and even greater compressive strengths than cubes made with TL and the controls. It is postulated that the higher content of sodium, calcium and solids in the leachate could have possibly contributed to the higher compressive strength. This study is the first of its kind to use leachate in concrete and supports the possibility that tropical landfill leachate can serve as a replacement of water in the making of concrete products.