Method for Stabilization and Solidification of a Lead-Contaminated Clayey Soil Using AAM Derived from Copper and Steel Slag

Lead-contaminated soils can be harmful to human health and the ecosystem. This paper investigates an approach for stabilization and solidification (S/S) of a lead-contaminated clayey soil using alkali-activated materials (AAMs) prepared by a combination of copper and steel slag. Regarding the limited environmental impact of AAMs in comparison with traditional cements, they have gained substantial attention to be used for S/S of contaminated soils. This study investigates the mechanical and chemical characteristics of clay specimens stabilized by AAMs under different lead concentrations, employing copper slag, steel slag, and their combinations as a hybrid binder. Two curing conditions, called ambient and oven, are considered, with curing durations ranging from 1 to 90 days. In addition to the uniaxial compressive strength (UCS) test, the toxicity characteristic leaching procedure (TCLP) is employed to evaluate the AAMs’ mechanical and chemical performance to remediate contaminated clayey soil. The results indicated that the curing condition significantly influences the compressive strength of stabilized soil, with ambient-cured samples showing continuous strength development. The hybrid binder, combining copper and steel slags, exhibits enhanced strength and denser AAM-derived formation than single binders. Lead leaching is effectively reduced, meeting the boundary values defined by current standards, especially with copper slag. This study introduces an eco-friendly and sustainable method for managing industrial by-products while addressing lead contamination. It presents a promising alternative to traditional methods, contributing to circular economy goals and addressing environmental concerns associated with cement production. This research develops the understanding of S/S mechanisms by AAM, offering insights for sustainable soil remediation approaches for heavy metal–contaminated cohesive soils.