Chloride binding in cement paste with calcined Mg-Al-CO3 LDH (CLDH) under different conditions

Geng, J, Pan, C, Wang, Y ORCID: https://orcid.org/0000-0003-4375-303X, Chen, W and Zhu, Y 2020, 'Chloride binding in cement paste with calcined Mg-Al-CO3 LDH (CLDH) under different conditions' , Construction and Building Materials , p. 121678.

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Abstract

The chloride binding capacity of cement paste with Mg-Al CLDH, obtained through calcining a commercial LDH, is investigated under different chloride concentration, environmental temperature, and concrete pore solution alkalinity conditions. The transformation mechanism of Mg-Al CLDH to Mg-Al-Cl LDH is mainly explored by means of X-ray diffraction (XRD) , Fourier-transform infrared spectroscopy (FT-IR) and Differential thermogravimetric analysis (DTG). There appears to be a threshold chloride concentration of 1.0 mol/L for Mg-Al CLDH (6% incorporation) effectively enhancing the chloride binding capacity of cement paste. Both lowering and raising (>38 °C) the environmental temperature is disadvantage to the transformation of Mg-Al CLDH to Mg-Al-Cl LDH in cement paste, and the amount of bound chloride at different curing temperatures follows as 38 °C > 50 °C ≈ 20 °C > 3 °C. Higher pore solution alkalinity is also adverse to both of the formation of Friedel’s salt and the rehydration of CLDH. With increasing pH from 12.5 to 13.5, the improvement of Mg-Al CLDH on the chloride binding capacity of cement paste became weaker. Mg-Al CLDH improves the chloride binding capacity of cement paste is not only related to the excellent anions exchanging ability of it , but also related to the promotion of Friedel’s salt formation of it.

Item Type: Article
Schools: Schools > School of Computing, Science and Engineering > Salford Innovation Research Centre
Journal or Publication Title: Construction and Building Materials
Publisher: Elsevier
ISSN: 0950-0618
Related URLs:
Funders: Natural Science Foundation of Zhejiang Province, Natural Science Foundation of China, Public welfare foundation of Ningbo city, Natural Science Foundation of Ningbo City
Depositing User: Y Wang
Date Deposited: 08 Dec 2020 10:26
Last Modified: 05 Jan 2021 13:30
URI: http://usir.salford.ac.uk/id/eprint/59041

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