MgO-GGBS Binder–Stabilized/Solidified PAE-Contaminated Soil: Strength and Leachability in Early Stage

Abstract

The MgO granulated ground blast-furnace slag (GGBS) binder, as a novel binder, has gained increasing attention in recent decades in stabilization/solidification (S/S) to treat contaminated soils. In this study, the physical strength and leaching performance of an MgO-GGBS (MG) binder was examined and compared with (PC) portland cement and PC and fly ash (PF) regarding the S/S treatment of dimethyl phthalates (PAE) contaminated soil after 7-day curing. PC, GGBS, fly ash (FA) and MgO were used as binders and the effect of different MG dosages was discussed. The results show that the order of early-stage strength after 7-day curing was: PF<MG<PC, and PAE leachate concentrations was in the order of MG<PC≈PF. The increase in MG dosage can improve the strength of binders and immobilize PAEs, while the increase of initial PAE concentrations (3,000–10,000 mg/kg) can reduce the strength and increase the leaching of PAE. Therefore, the MG binder showed a better performance for the S/S of PAE-contaminated soil than PC and PF binders. The relation between leachability and strength was further explored and is expected to provide guidance for the early-stage strength estimation after the S/S of PAE-contaminated clay soil with the MG binder.