Al Content Effect on Microstructure and Strength in Calcium Aluminosilicate Hydrate Chain Integration

• Published in: Strength of materials Vol. 54; no. 5; pp. 929 - 941
• Main Authors: Zhou, C. S., Tang, Q., Lu, L.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2022; Springer; Springer Nature B.V
• Subjects: Aluminosilicates; Aluminum; Aluminum silicates; Analysis; Calcium ions; Cement paste; Chain branching; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Dynamic structural analysis; Gels; Materials Science; Mechanical properties; Microstructure; Modulus of elasticity; Molecular dynamics; Polymerization; Silicon; Solid Mechanics; Structural models; Trajectory analysis; molecular dynamics simulation; microstructure; Al-doping; calcium aluminosilicate hydrate; elastic modulus
• ISSN: 0039-2316; 1573-9325
• DOI: 10.1007/s11223-022-00469-1

The microstructure and mechanical properties of calcium aluminosilicate hydrate (C-A-S-H) were investigated using CLAYFF force field molecular dynamics simulations. A computational study was conducted to define a structural model for C-A-S-H gels formed in Al-containing cement pastes. A series of amorphous C-A-S-H were constructed randomly starting from the building blocks, including Ca 2+ , Al 3+ , Si 4+ , O 2- , OH - , and H 2 O. Trajectory analysis shows that the polymerization degree of the SiO 4 chain did not change with increasing Al content. Instead, AlO 4 acted as a chain linker to form the Si-O-Al structure and the branching network structure of the C-A-S-H phase. Meanwhile, the integration of Al into C-S-H had little effect on the elastic modulus of C-S-H. Theoretical simulation results are in good agreement with many experimental data and indicate the universal applicability of the stochastic packing C-A-S-H modeling method to describe the microstructure and mechanical properties of C-A-S-H.