Lawrence Berkeley National Laboratory
A high-pressure X-ray diffraction study of the crystalline phases in calcium aluminate cement paste
- Author(s): Geng, Guoqing
- Li, Jiaqi
- Zhou, Yang
- Liu, Lin
- Yan, Jinyuan
- Kunz, Martin
- Monteiro, Paulo JM
- et al.
Published Web Locationhttps://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=+A+high-pressure+X-ray+diffraction+study+of+the+crystalline+phases+in+calcium+aluminate+cement+paste&btnG=#d=gs_cit&u=%2Fscholar%3Fq%3Dinfo%3AKxX6EBBsv7cJ%3Ascholar.google.com%2F%26output%3Dcite%26scirp%3D0%26hl%3Den
© 2018 Elsevier Ltd Calcium aluminate cement (CAC) has wide application in civil engineering and castable refractory materials. The main binding phases of hardened CAC paste, CaO·Al 2 O 3 ·10H 2 O (CAH 10 ), inevitably converts to 2CaO·Al 2 O 3 ·8H 2 O (C 2 AH 8 ), 3CaO·Al 2 O 3 ·6H 2 O (C 3 AH 6 ) and Al(OH) 3 (AH 3 ), leading to a significant change in the mechanical properties of the CAC matrix. This work investigates the mechanical properties of the main crystalline components in hydrated and/or converted CAC systems, using synchrotron-radiation-based high-pressure X-ray diffraction. The anisotropic deformations of CaAl 2 O 4 (CA), CAH 10 and C 3 AH 6 along each crystallographic direction are investigated, along with their bulk moduli. The density-driven stiffening hypothesis is validated for the studied phases and other cement-based minerals. An atom-scale topological analysis is proposed to explain the unusually high stiffness of CAH 10 . The results provide fundamental information to understand the mechanical properties of single cement-based phases at molecular level, and enable predicting the changing mechanical properties of converted CAC matrix using homogenization models.