Nature of Interatomic Bonding in Controlling the Mechanical Properties of Calcium Silicate Hydrates

Journal Article · Wed Mar 09 00:00:00 EST 2016 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/jace.14214· OSTI ID:1400547

Dharmawardhana, Chamila ^[1]; Bakare, Morayo ^[2]; Misra, Anil ^[3]; Ching, Wai‐Yim ^[1]; Bullard, ed., J.

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1. Department of Physics and Astronomy University of Missouri – Kansas City 5110 Rockhill Road Kansas City Missouri 64110
2. Department of Mechanical Engineering University of Missouri – Kansas City 5110 Rockhill Road Kansas City Missouri 64110
3. Department of Civil, Environmental, and Architectural Engineering University of Kansas 1530 W 15^th Street Lawrence Kansas 66045

Calcium silicate hydrate (C–S–H) is the most important phase of hydrated cement gel which is the key material in construction industry. It is well accepted that hardened cement paste consists of either poorly crystalline or completely disordered phases. Although a myriad of speculative atomistic models of disordered C–S–H have been proposed, the fundamental basis of structure–property relationships remain elusive. This study focuses upon the correlations between mechanical properties and electronic structure based on well‐defined quantum mechanical parameters. We use 20 CSH minerals with known structure to gain fundamental understanding of structure–property relationship. The results indicate Si–O bond order density, which represents the cumulative bond strength of SiO bonds, has no direct correlation with bulk mechanical properties which is counterintuitive and against conventional wisdom. The variations are determined more precisely by the overall atomic and electronic structure dictated by bond order density of the Ca–O and hydrogen bonds ( HB ). Most importantly, there is a multifaceted balance between different types of interatomic bonds including the HB s in controlling mechanical properties. HB s categorized in relation to next nearest neighbor ( NNN ) enable us to identify specific types of HB s that are prevalent in CSH . In certain crystals such as suolunite, the HB network is organized in such a unique way that enhances its mechanical properties. The approach and findings presented in this paper points to a broad roadmap for the developing next‐generation cements.

• Sponsoring Organization: USDOE
• Grant/Contract Number: DE‐AC03‐76SF00098
• OSTI ID: 1400547
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Vol. 99 Journal Issue: 6; ISSN 0002-7820
• Publisher: Wiley-Blackwell
• Country of Publication: United States
• Language: English