Evaluation of sand-clay-anionic polyacrylamide blends for alternative compacted clay landfill liner design

In this project, an innovative low hydraulic conductivity material for landfill cover and liner construction was studied. The material is a blend of natural clayey soil from Comodoro Rivadavia city (Chubut province, Argentina) mixed with fine uniform sand and anionic polyacrylamide (APAM). The research emphasizes understanding the influence of APAM addition on the soil water retention capacity (SWRC), unsaturated hydraulic conductivity, and swelling behavior. APAM is a super absorbent polymer that swells when immersed in water. SWRC was evaluated through the filter paper method. The unsaturated hydraulic conductivity and swelling behavior were determined using two fluids: distilled water and brine (C = 2 M). Results showed that APAM addition reduced the blends' microporosity, increased the water retention capacity, and reduced the hydraulic conductivity of the system. These promising results encourage further research on these blends' behavior to determine the most efficient blend formulation to enhance its hydro-mechanical performance and its chemical compatibility with landfill leachates for cover and low hydraulic conductivity liner layer construction.