Use of self-hardening slurry for trench cutoff wall: A review

Abstract

Landfilling is still the most commonly adopted means for disposal of industrial and municipal solid wastes in the world. However, contaminants from these untreated wastes may spread out with lapse of time and pollute soil and groundwater nearby, which can destroy ecological environment and threaten human's health. Thus, the encapsulation technology is usually applied for preventing spreading of the contaminants. Self-hardening slurry is prevalently used to form cutoff wall as vertical barriers for the control of horizontal migration of contaminants at those sites, due to its technological efficiency, easy operation and handling over other vertical barrier materials. This study comprehensively reviewed and assessed key properties of four types of self-hardening slurry, namely, cement-bentonite (CB) slurry, slag-cement-bentonite (SCB) slurry, fly ash–cement-bentonite (FCB) slurry and Impermix slurry. Emphasis has been put on unconfined compressive strength (UCS), permeability coefficient and chemical compatibility, which characterize the overall performances of these slurries. Apart from conventional factors, some hidden factors, such as cast-into position, depth and confining pressure, water table and scale effect etc., affecting the performance of self-hardening slurries were simultaneously investigated to shed light on the limitations and perspectives in the application of these materials.