Leaching and microstructural properties of lead contaminated kaolin stabilized by GGBS-MgO in semi-dynamic leaching tests

Wu, H.-L., Jin, F. , Bo, Y.-L., Du, Y.-J. and Zheng, J.-X. (2018) Leaching and microstructural properties of lead contaminated kaolin stabilized by GGBS-MgO in semi-dynamic leaching tests. Construction and Building Materials, 172, pp. 626-634. (doi:10.1016/j.conbuildmat.2018.03.164)

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Abstract

Ground granulated blast furnace slag (GGBS) is widely used to stabilize soils due to its environmental and economic merits. The strength and durability of reactive MgO activated GGBS (GGBS-MgO) stabilized lead (Pb)-contaminated soils have been explored by previous studies. However, the effects of simulated acid rain (SAR) on the leachability and micro-properties of GGBS-MgO stabilized Pb-contaminated soils are hardly investigated. This research studies the leachability and microstructural properties of GGBS-MgO stabilized Pb-contaminated kaolin clay exposed to SAR with initial pH values of 2.0, 4.0 and 7.0. A series of tests are performed including the semi-dynamic leaching tests using SAR as the extraction liquid, acid neutralization capacity (ANC), mercury intrusion porosimetry (MIP), and X-ray diffraction (XRD) tests. The results demonstrate that as the SAR pH decreases from 7.0 to 4.0, the Pb cumulative fraction leached (CFL) and observed diffusion coefficient (Dobs) increases significantly whereas the leachate pH decreases. Meanwhile, increasing the GGBS-MgO content from 12% to 18% results in the decrease of CFL and Dobs. Further decreasing the SAR pH to 2.0 results in the dissolution-controlled leaching mechanism regardless of the binder dosage. The differences in the leaching properties under different pH conditions are interpreted based on the cemented soil acid buffering capacity, hydration products and pore size distributions obtained from the ANC, MIP, and XRD tests, respectively.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Jin, Dr Fei
Authors: Wu, H.-L., Jin, F., Bo, Y.-L., Du, Y.-J., and Zheng, J.-X.
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Journal Name:Construction and Building Materials
Publisher:Elsevier
ISSN:0950-0618
ISSN (Online):1879-0526
Published Online:05 April 2018
Copyright Holders:Copyright © 2018 Elsevier
First Published:First published in Construction and Building Materials 172:626-634
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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