title: Three-year performance of in-situ mass stabilised contaminated site soils using MgO-bearing binders.
abstract: This paper provides physical and chemical performances of mass stabilised organic and inorganic contaminated site soils using a new group of MgO-bearing binders over 3 years and evaluated the time-dependent performance during the 3 years. This study took place at a contaminated site in Castleford, UK in 2011, where MgO, ground granulated blastfurnace slag (GGBS) and Portland cement (PC) were mixed with the contaminated soils in a dry form using the ALLU mass mixing equipment. Soil cores were retrieved 40-day, 1-year and 3-year after the treatment. The core quality, strength, and the leaching properties were determined via physical observation, unconfined compressive strength (UCS) and batch leaching tests. After 3-year treatment, the UCS values of ALLU mixes were in the range of 50-250kPa; the leachate concentrations of Cd, Pb, Cu and Zn (except Ni) in all mixes were lower than their drinking water standards; and the leachability of total organics was in the range of 10-105mg/L. No apparent degradation of the mass stabilised materials after 3 years' exposure to the field conditions was found. MgO-GGBS blends were found able to provide higher strength and less leachability of contaminants compared to PC and MgO-only mixes in mass stabilised soils.
authors.affiliation: Institute of Geotechnical Engineering, School of Transportation, Southeast University, Nanjing, 210096, China; Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK. Electronic address: 101012020@seu.edu.cn.
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK. Electronic address: fj232@cam.ac.uk.
authors.forename: Fei
authors.initials: F
authors.lastname: Jin
authors.affiliation: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK. Electronic address: zs281@cam.ac.uk.
authors.forename: Zhengtao
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK. Electronic address: aa22@cam.ac.uk.
authors.forename: Abir
authors.initials: A
authors.lastname: Al-Tabbaa
keywords: GGBS; In-situ mass stabilisation; Leachability; MgO; Strength