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Cl− adsorption and intercalated ions release processes during LDHs are highly intricate phenomena. In this study, ion exchange performance of LDHs with specific cation interlayers and intercalated anions (CaAl–NO 3 -LDHs, CaAl–NO 2 -LDHs, CaFeAl–NO 3 -LDHs and CaFeAl–NO 2 -LDHs) were extensively investigated. The results indicate that in the presence of low chloride concentration, the intercalated anions are prematurely released due to partial dissolution of LDHs in neutral deionized water and ion exchange with OH− in alkaline simulated concrete pore solution. Therefore, Cl− adsorption of LDHs and release process of intercalated anions in LDHs are not completely synchronized. Compared to partial LDHs dissolution, the accelerating effect of OH− exchange on intercalated anion release in simulated concrete pore solution is more pronounced. Further, higher stability of LDHs in testing solutions is mainly corresponding to higher binding energy between intercalation ions and cation interlayers, thus saturated Cl− adsorption content of NO 3 -LDHs with high binding energy is higher than NO 2 -LDHs with low binding energy, and saturated Cl− adsorption content of CaAl-LDHs with high binding energy is higher than CaFeAl-LDHs with low binding energy in testing solutions. • Introducing Fe into cationic interlayers reduces the stability of the formed LDHs. • LDHs are partially dissolved in deionized water to maintain high alkalinity. • Intercalated anions in LDHs exchange with OH− to form OH-LDHs in SCP solution. • Asynchronous Cl− adsorption and intercalated anions release exist in solutions. • Higher E B prohibits LDHs dissolution and OH− exchange, improving Cl− adsorption. [ABSTRACT FROM AUTHOR]

The mechanical properties, phase evolution, microstructure development and (re)hydration properties of limestone calcined clay cement (LC3) paste and mortar were investigated to understand their thermal stability under moderate temperatures (100–400 °C). The residual compressive strengths of LC3 and Portland cement (PC) mortars kept constant or slightly increased from ambient to 300 °C, and sharply dropped at 400 °C. At 100 °C, monocarboaluminate (Mc) and ettringite (AFt) converted into hemicarboaluminate (Hc) and monosulfate (Ms), and caused partial dehydroxylation of C-(A)-S-H. As the temperature increased, at 200–300 °C, due to the decomposition of large fraction of hydration products, macroscopic cracks and microstructure damage occurred. At 400 °C, the mean chain length (MCL) of C-(A)-S-H gel decreased, accompanied by the shift of Si and Al-coordination number and the formation of active sites. Under water saturation conditions, the microstructure showed self-repairing performance. [ABSTRACT FROM AUTHOR]