Mechanical, hydraulic, and chemical behavior of steel slag-amended loessical silt–bentonite liners

Abstract

Liners are engineered layers of low hydraulic conductivity designed to isolate solid, semisolid, or liquid wastes from the environment. Most common materials for liners construction are natural soils amended with bentonite to achieve the low hydraulic conductivity specified by current regulations. This work evaluates the potential reuse of steel slag to improve the performance of landfill liners. We evaluate the effect of adding slag to soil on its mechanical and reactive properties when compacted. Used soil is a loessical silt from the center of Argentina which is frequently used for the construction of bottom liners. The effect of slag content and curing time on the unconfined compression strength of slag–silt mixtures is assessed. Obtained values are incorporated in contaminant transport models to evaluate the transport of metal ions present in leachate through landfill barriers. Results show that the retention of metal ions within a compacted barrier amended with steel slag is mainly associated with the increase of the pH of the barrier material.