Strength and electrical conductivity characteristics of zinc contaminated soil carbonated/stabilized with GGBS-reactive MgO

In this study, the compound binder of ground granulated blast furnace slag (GGBS)-reactive MgO is used for the carbonization/stabilization treatment of zinc (Zn)-contaminated soil. The unconfined compression and electrical conductivity tests on the carbonated/stabilized Zn-contaminated soil are conducted, and the uncarbonated Zn-contaminated soil after 28-day standard curing is used for comparison. The effects of Zn-ion concentration and binder mixing ratio on the unconfined compressive strength (q_u) of the carbonated/stabilized soils and the conductivity of the pore fluid are investigated. The test results indicate that: (1) When the mixing ratio of curing agent is fixed, the q_u of the carbonated Zn- contaminated soil first increases and then decreases with the increase of Zn ion concentration, while the conductivity increases. (2) When the content of Zn-ion concentration is fixed, the q_u of the carbonated Zn-contaminated soil increases with the increase of reactive MgO content in the binder, but its conductivity decreases slightly. (3) The q_u of the carbonated zinc contaminated soil is higher compared with that of the noncarbonated Zn- contaminated soil (28-day standard curing), but the conductivity is almost the same. This study will provide a new approach for the reuse of industrial wastes and carbon dioxide as well as the low-carbon treatment of Zn-contaminated soil, and be of important significance for accelerating the "carbon peak".