Mechanical Properties and Leaching Characteristics of Geopolymer-SolidifiedStabilized Lead-Contaminated Soil

Abstract EN

Ordinary Portland cement (OPC) is widely used in the solidification/stabilization of Pb-contaminated soils.

However, many studies have suggested that the high content of Pb would degrade the mechanical properties of OPC-solidified/stabilized soils.

This paper presents a new binder, geopolymer fine aggregate (GFA), composed of ground granulated blast furnace slag, fly ash, CaO, and Na2SiO3.

For comparison, OPC was used as a conventional binder.

Mechanical properties and leaching characteristics are typically used to evaluate the effects of binders on solidified/stabilized soils.

Nevertheless, limited information on the mechanical properties and leaching characteristics of the GFA-solidified/stabilized soils is available.

This study thus investigated the mechanical properties and leaching characteristics of geopolymer-solidified/stabilized Pb-contaminated soil.

Unconfined compressive strength test, permeability test, synthetic precipitation leaching procedure, simplified bioaccessibility extraction, phytoavailability extraction (with diethylene-triamine penta-acetic acid), sequential extraction procedure, mercury intrusion porosimetry, and scanning electron microscopy (SEM) were performed on OPC- and GFA-solidified/stabilized soil.

The results showed that the GFA presented a better effect on the mechanical properties and leachability of the solidified/stabilized soils than the OPC-solidified/stabilized soils.

The GFA-solidified/stabilized soil displayed considerably lower leachability, bioaccessibility, and phytoavailability of Pb and higher mechanical properties and chemical stability than the OPC counterpart.

This study demonstrated that GFA had a better effect than OPC on the solidification/stabilization of Pb-contaminated soils.