Cutoff wall is one of the most effective technologies for the soil and groundwater contamination control. However, conventional backfill consisting of ordinary portland cement (OPC) inevitably deteriorate under mechanical, chemical, and environmental stresses. The damage of cut-off walls can undermine their mechanical properties and durability, impacting their serviceability and reliability. This paper proposed an innovative geopolymer cutoff wall backfill (GCWB) that is composed of fly ash (FA), sodium silicate (Na2SiO3) and sand. On this basis, bentonite with different content was further added to improve the durability, thus forming geopolymer-bentonite cutoff wall backfill (GBCWB). The hydraulic conductivity of GBCWB were tested, then the optimal material ratio was determined. In order to evaluate the durability of GBCWB in dry-wet cycle test, the microstructural characteristics were assessed by Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS). The overall performance proved that GBCWB is promising to be used in contamination control.
9th International Congress on Environmental Geotechnics (ICEG2023)
Contaminant Fate and Transport