Improving sulfate attack resistance of concrete by using calcined Mg-Al-CO3 LDHs: Adsorption behavior and mechanism
Article
Article Title | Improving sulfate attack resistance of concrete by using calcined Mg-Al-CO3 LDHs: Adsorption behavior and mechanism |
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ERA Journal ID | 3470 |
Article Category | Article |
Authors | Guo, Liang (Author), Wu, Yueyue (Author), Duan, Ping (Author) and Zhang, Zuhua (Author) |
Journal Title | Construction and Building Materials |
Journal Citation | 232, pp. 1-11 |
Article Number | 117256 |
Number of Pages | 11 |
Year | 2020 |
Publisher | Elsevier |
Place of Publication | Netherlands |
ISSN | 0950-0618 |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.conbuildmat.2019.117256 |
Web Address (URL) | https://www.sciencedirect.com/science/article/pii/S0950061819327084 |
Abstract | In this work, the impact of layered double hydroxides (LDHs) on sulfate attack resistance of concrete was explored. Replacement level of cement by calcined Mg-Al CO3 LDHs was 2%. Mechanism of ion exchange and memory effects of LDHs has been revealed from structure evolution and adsorption behavior aspects of LDHs in aqueous solution. The efficiency of calcined LDHs in sulfate attack resistance was also assessed in terms of microstructure and compressive strength loss of concrete. The experimental results show that structure regeneration of calcined LDHs can be achieved based on memory effect and ion adsorption after mixing with solution. Calcined LDHs presents high sulfate ion adsorption capacity ascribes to the availability of large amounts of vacancy between the layers. The optimal dosage of calcined LDHs for achieving high uptake efficiency of sulfate ion surpasses 3.0 g/L. Langmuir isotherm suits more to describe the adsorption of sulfate ion on calcined LDHs compared with Freundlich model. Thermodynamic parameters calculation indicates the endothermic behavior (the maximum value is obtained at 40 °C) and spontaneous nature of sulfate ion adsorption on the calcined LDHs. Calcined LDHs exhibits improving effect on pore refinement. Calcined LDHs improves concrete strength and therefore enhances sulfate attack resistance especially at longer exposure days. |
Keywords | Layered double hydroxides; Sulfate attack; Adsorption; Compressive strength |
ANZSRC Field of Research 2020 | 400505. Construction materials |
Byline Affiliations | China University of Geosciences, China |
Centre for Future Materials | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q5863/improving-sulfate-attack-resistance-of-concrete-by-using-calcined-mg-al-co3-ldhs-adsorption-behavior-and-mechanism
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