A high-pressure X-ray diffraction study of the crystalline phases in calcium aluminate cement paste

作者：Geng, Guoqing^*; Li, Jiaqi; Zhou, Yang; Liu, Lin; Yan, Jinyuan; Kunz, Martin; Monteiro, Paulo J. M.

来源：Cement and Concrete Research, 2018, 108: 38-45.

DOI：10.1016/j.cemconres.2018.03.004

• Calcium aluminate cement (D)
• Mechanical properties (B)
• High-pressure X-ray diffraction
• Crystal structure (B)

Calcium aluminate cement (CAC) has wide application in civil engineering and castable refractory materials. The main binding phases of hardened CAC paste, CaO center dot Al2O3 center dot 10H(2)O (CAH(10)), inevitably converts to 2CaO center dot Al2O3 center dot 8H(2)O (C(2)AH(8)), 3CaO center dot Al2O3 center dot 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 CaAl2O4 (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.

• 出版日期2018-6
• 单位河海大学; 东南大学