CUED Publications database

Cement-fly ash stabilisation/solidification of contaminated soil: Performance properties and initiation of operating envelopes

Kogbara, RB and Al-Tabbaa, A and Yi, Y and Stegemann, JA (2013) Cement-fly ash stabilisation/solidification of contaminated soil: Performance properties and initiation of operating envelopes. Applied Geochemistry, 33. pp. 64-75. ISSN 0883-2927

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Abstract

This study was aimed at evaluating the mechanical and pH-dependent leaching performance of a mixed contaminated soil treated with a mixture of Portland cement (CEMI) and pulverised fuel ash (PFA). It also sought to develop operating envelopes, which define the range(s) of operating variables that result in acceptable performance. A real site soil with low contaminant concentrations, spiked with 3000mg/kg each of Cd, Cu, Pb, Ni and Zn, and 10,000mg/kg of diesel, was treated with one part CEMI and four parts PFA (CEMI:PFA=1:4) using different binder and water contents. The performance was assessed over time using unconfined compressive strength (UCS), hydraulic conductivity, acid neutralisation capacity (ANC) and pH-dependent leachability of contaminants. With binder dosages ranging from 5% to 20% and water contents ranging from 14% to 21% dry weight, the 28-day UCS was up to 500kPa and hydraulic conductivity was around 10-8m/s. With leachant pH extremes of 7.2 and 0.85, leachability of the contaminants was in the range: 0.02-3500mg/kg for Cd, 0.35-1550mg/kg for Cu, 0.03-92mg/kg for Pb, 0.01-3300mg/kg for Ni, 0.02-4010mg/kg for Zn, and 7-4884mg/kg for total petroleum hydrocarbons (TPHs), over time. Design charts were produced from the results of the study, which show the water and/or binder proportions that could be used to achieve relevant performance criteria. The charts would be useful for the scale-up and design of stabilisation/solidification (S/S) treatment of similar soil types impacted with the same types of contaminants. © 2013 Elsevier Ltd.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div D > Geotechnical and Environmental
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 12:14
Last Modified: 08 Dec 2014 02:19
DOI: 10.1016/j.apgeochem.2013.02.001