Novel understanding of calcium silicate hydrate from dilute hydration

• Published in: Cement and concrete research Vol. 99; pp. 95 - 105
• Main Authors: Zhang, Lina, Yamauchi, Kazuo, Li, Zongjin, Zhang, Xixiang, Ma, Hongyan, Ge, Shenguang
• Format: Journal Article
• Language: English
• Published: Elmsford Elsevier Ltd 01.09.2017; Elsevier BV
• Subjects: C-S-H; C3S hydration; Calcium; Calcium silicate hydrate; Calcium silicates; Cement; Clusters; Composition; Crystal structure; Crystallinity; Crystallization; Dilution; Dissolution; Foils; Hydration; Migration; NMR; Nuclear magnetic resonance; Scanning electron microscopy; Silicon; Slaked lime; Structure; Studies; Tricalcium silicate; C-S-H; Composition; C3S hydration; Crystallinity; Structure
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2017.04.016

The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10 was conducted for tricalcium silicate (C3S) to interpret long-term hydration process and investigate the formation, structure and properties of C-S-H. Based on results from XRD, IR, SEM, NMR and so forth, loose and dense clusters of C-S-H with analogous C/S ratio were obtained along with the corresponding chemical formulae proposed as Ca5Si4O13∙6.2H2O. Crystalline structure inside C-S-H was observed by TEM, which was allocated at the foil-like proportion as well as the edge of wrinkles of the product. The long-term hydration process of C3S in dilute suspension could be sketchily described as migration of calcium hydroxide and in-situ growth of C-S-H with equilibrium silicon in aqueous solution relatively constant and calcium varied.