Micromechanical properties of calcium silicate hydrates and ettringite: Preliminary study on the single and mixed products

N Wang and HX Zhong and XG Xu and L Yang and WQ Zhang and ZB Lei and J Liu and FZ Wang and YL Deng and JH Lu, JOURNAL OF BUILDING ENGINEERING, 111, 113282 (2025).

DOI: 10.1016/j.jobe.2025.113282

The hydration of high-ferrite cement (HFC) involves complex interactions among four minerals, leading to the formation of Aluminum-containing calcium silicate hydrates (CASH) and ironcontaining ettringite (AFt-Fe). To investigate the interaction mechanisms between Al/Fe and hydrates, as well as their effects on micromechanical properties, CSH/CASH and AFt/AFt-Fe were synthesized and analyzed in terms of crystal structure, micromorphology, and pore size distribution. The incorporation of Al and Fe increases the elastic modulus of CSH and AFt, respectively. However, the mixture of CASH and AFt-Fe exhibits a lower elastic modulus than either component alone. Molecular dynamics (MD) simulations further elucidated the effects of Al and Fe on the structure of hydrates and their interactions with surrounding particles. Aluminum did not alter the fundamental structure of CSH but increased the elastic modulus through Al-O bonds, which are longer than Si-O bonds and easier to form cross-linking points between layers. The enhanced elastic modulus for the incorporation of Fe into AFt was from the disordered water molecules in crystal structure, which promoted hydrogen bond network formation. This work illuminates the significance of Al and Fe on in the microscopic mechanical properties of cement.

Return to Publications page