Uptake of chloride and carbonate by Mg-Al and Ca-Al layered double hydroxides in simulated pore solutions of alkali-activated slag cement
Year: 2017
Type: article
Abstract: Chloride ingress and carbonation are major causes of degradation of reinforced concrete. To enable prediction of chloride ingress, and thus to improve the durability of structural alkali-activated slag cement (AAS) based concretes, it is necessary to understand the ionic interactions taking place between chlorides, carbonates, and the individual solid phases which comprise AAS. This study focused on two layered double hydroxides (LDH) representing those typically identified as reaction products in AAS: an Mg-Al hydrotalcite-like phase, and an AFm structure (strätlingite), in simulated AAS pore solutions. Surface adsorption and interlayer ion-exchange of chlorides occurred in both LDH phases; however, chloride uptake in hydrotalcite-group structures is governed by surface adsorption, while strätlingite shows the formation of a hydrocalumite-like phase and ion exchange. For both Ca-Al and Mg-Al LDHs, decreased chloride uptakes were observed from solutions with increased [CO32−]/[OH−] ratios, due to the formation of carbonate-containing hydrotalcite and decomposition of AFm phases, respectively.
Source: Cement and Concrete Research
Authors: Xinyuan Ke, Susan A. Bernal, John L. Provis
Institution: University of Sheffield
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,180
Funders: U.S. Department of Energy, Department of Energy and Climate Change, European Commission, University of Sheffield, China Scholarship Council, Engineering and Physical Sciences Research Council, European Research Council, Seventh Framework Programme, H2020 European Research Council, FP7 Ideas: European Research Council
OpenAlex ID: W2619899540