Atomistic modelling of crystal structures of Friedel's salts Ca2Al(OH)6(Cl,CO3,OH)·mH2O: Its relation to chloride binding
Artikel i vetenskaplig tidskrift, 2025

The diffusion of chloride critically affects the durability of reinforced concrete in exposure environments. Hydrocalumite-like (AFm) phases can bind chlorides to form Friedel's salts, retarding chloride ingress. However, the stability and structural parameters of Friedel's salts with mixed-anion interlayers are not fully understood. First principles computation was performed to provide the energy-minimum crystal structures for Friedel's salt and AFm phases with various substitutions and water contents. It shows that the mixing of Cl− and OH− significantly changes the lattice parameters. However, the mixing of 1/2CO32− and Cl− anion presents little effect on structural parameter. It is energetically favourable and hardly measurable by XRD but decreases chloride binding capacity. The interlayer hydroxide ions show considerable flexibility in terms of occupied sites, which may be a key factor for the stability of AFm phases. The modelling results align with the the structural changes of Friedel's salts reported in previous experiments.

Chloride binding

First principles computation

Friedel's salts

AFm

Författare

Liming Huang

Chalmers, Arkitektur och samhällsbyggnadsteknik, Byggnadsteknologi

Erik Bialik

Molecules in Motion

Arezou Baba Ahmadi

Chalmers, Arkitektur och samhällsbyggnadsteknik, Byggnadsteknologi

Cement and Concrete Research

0008-8846 (ISSN)

Vol. 191 107821

Ämneskategorier (SSIF 2025)

Fysikalisk kemi

DOI

10.1016/j.cemconres.2025.107821

Mer information

Senast uppdaterat

2025-03-07