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.
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