Performance Evaluation of Stabilised/Solidified Contaminated Model Soil Using PC-Based and MgO-Based Binders
The physical and chemical performances of stabilised/solidified contaminated model soil were investigated to reveal the benefit of stabilisation/solidification treatment using novel binders over conventional binders. Different combinations of binders selected from materials including Portland cement (PC), ground granulated blastfurnace slag (GGBS), pulverised fly ash (PFA) and magnesia (MgO) were mixed with contaminated soil, the water/cement (w/c) ratio at 0.5:1 was used in this study. The strength and the leaching properties of these mixes via the unconfined compressive strength (UCS) test and the batch leaching test are presented. The immobilisation degree under different mixes and strength difference under two w/c ratios are discussed. The results show that although less binder dosage was applied in mixes with a w/c ratio at 0.5:1, all these mixes produced higher UCS values than mixes with a w/c ratio at 1:1 (the ratio used in the field taken from previous studies). Moreover, the leachate concentrations of Ni, Cu and Zn in all mixes were far below their drinking water standards at 0.02 mg/l, 2 mg/l and 3 mg/l, respectively. Although most mixes cannot meet the regulative requirement of immobilising Pb, the Pb immobilisation degrees of MgO-based mixes (>99.95%) were found higher than PC-based mixes (98.8%).
KeywordsHeavy metals Strength Stabilisation/solidification MgO Soil remediation
This research is financially supported by the National Natural Science Foundation of China, China (Grant No. 51608113). The second author would like to thank the Killam Trusts of Canada for kindly providing the Izaak Walton Killam Memorial Postdoctoral Fellowship.
- Abunada Z (2015) Innovative soil mix technology constructed permeable reactive barrier for groundwater remediation. PhD thesis, University of CambridgeGoogle Scholar
- Al-Tabbaa A (2013) Reactive magnesia cement, pp 523–543Google Scholar
- BS EN 12457-2 (2002) Characterisation of waste-leaching-compliance test for leaching of granular waste materials and sludges. British Standard, UKGoogle Scholar
- Conner JR (1990) Chemical fixation and solidification of hazardous wastes. Van Nostrand Reinhold, New YorkGoogle Scholar
- Harrison J (2003) The case for and ramifications of blending reactive magnesia with Portland cement. In: 28th conference on our world in concrete and structures, SingaporeGoogle Scholar
- Jin F (2014) Characterisation and performance of reactive MgO-based cements with supplementary cementitious materials. PHD thesis, Cambridge University, UKGoogle Scholar
- The Private Water Supplies Regulations, HMSO, Water England Document No. 3101 (2009)Google Scholar
- Wang F, Al-Tabbaa A (2014) Leachability of 17-year old stabilised/solidified contaminated site soils. In: GeoCongress 2014: geo-characterization and modeling for sustainability, ASCE, Atlanta, GeorgiaGoogle Scholar
- Wang F, Shen Z, Al-Tabbaa A (2018) PC-based and MgO-based binders stabilised/solidified heavy metal contaminated model soil: strength and heavy metal speciation in early stage. https://doi.org/10.1680/jgeot.17.p.194
- Wastewater Technology Centre (1991) Proposed evaluation protocol for cement-based solidified wastes. Report EPS 3/HA/9, Environment CanadaGoogle Scholar
- Wheeler P (1995) Leachate repellent. Ground Eng 28(5):20–22Google Scholar
- Zampetakis T, Yiannoulakis H, Meidani A et al (2014) Use of magnesia cement in industrial waste cementation. In: 34th cement and concrete science conference 2014, University of SheffieldGoogle Scholar