Recycling of phosphogypsum and red mud in low carbon and green cementitious materials for vertical barrier

MgO activated slag and bentonite (MASB) slurry is a new and promising vertical barrier material along with excellent performances. Some solid wastes, such as phosphogypsum (PG), red mud (RM), fly ash and so on, show a positive effect on the performances of alkali activated slag. However, few studies focus on the recycling of these solid wastes in the system of MgO activated slag. The purpose of this paper is to study the incorporation of phosphogypsum and red mud on the mechanical property, permeability and hydration process of MASB slurry. The results showed that the addition of PG could significantly improve the mechanical strength and anti-permeability of the MASB slurry at early age (7 days), where the unconfined compressive strength (UCS) increased from 793.1 kPa to 1395.7 kPa and the permeability coefficient declined from 16.1 × 10