Evaluating hydraulic conductivity of soil-waste mixtures for use in sanitary landfill waterproof barriers

Abstract Soilwaste has become an economically viable and sustainable solution in geotechnical engineering, whereas many industrial tailings, when associated with other materials are able to satisfy the properties required in projects. This study aimed to form incorporated soil mixtures with two types of waste aiming to use them in landfill liners. Six soil-waste mixtures were developed, where the waste quantity and the compaction energy were varied. They were normal (NOR) and modified (MOD). The formulated mixtures were: 0R-NOR, 10LM-NOR, 10AG-NOR, 0R-MOD, 10LM-MOD and 10AG-MOD, where 10LM means an addition of 10% lime-mud and 10AG means an addition of 10% agricultural-gypsum, both in relation to dry soil mass. The mixtures were subjected to the variable load permeability test to verify them in terms of the required liner parameters. It is worth mentioning that both compaction energy and waste addition were able to reduce soil permeability, however, the percentage of material added to the mixture was not sufficient to reach values lower than E-07 cm/s.