Seepage water quality of a soil treated with alkali-activated cement at room temperature

Modern societies are great producers of waste because of their energy and natural resource needs. Many of these wastes are disposed of in landfills, which require a significantly sized area of soil and special geotechnical conditions. The reaction between alumina-silicate and an aqueous alkali hydroxide and silicate solution produces an alkali-activated cement (AAC). The use of AAC, an inorganic material with a chemical structure of polymeric Si–O–Al bonds, can promote the stabilisation and immobilisation of a wide variety of waste sources containing hazardous materials. The purpose of this study is to evaluate the effect of curing conditions on the resistance and permeability and in the quality of the seepage water generated over time in transport infrastructure platforms built with soil stabilised with AAC. The strength results show that the material meets the requirements for use in building low-cost roads. Permeability tests of AAC samples show a relatively low permeability (between 10⁻⁸ and 10⁻⁷ m/s), a positive factor for environmental and geotechnical considerations. However, this permeability still results in significant leachate water with quality and contaminant issues, particularly in chromium (Cr), cadmium (Cd), aluminium (Al), sodium and silicon (Si), and high pH.