Aluminum-induced structure evolution and mechanical strengthening of calcium silicate hydrates : an atomistic insight

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Detail(s)

Original languageEnglish
Article number132120
Journal / PublicationConstruction and Building Materials
Volume393
Online published13 Jun 2023
Publication statusPublished - 22 Aug 2023

Abstract

How Al3+ dissolved from supplementary cementitious materials influences the performance of cement paste is far from being fully understood, especially from an atomistic insight. Herein, Al3+ is introduced into calcium silicate hydrate (CSH, the main phase of cement paste) to evaluate its effect using atomistic simulation. Structurally, Al3+ heals defects in the silicate chains, forms cross-links between calcium aluminosilicate layers, and reduces interlayer space and H2O content. The chemical stability of interlayer H-bonds and Ca-O bonds is also improved. The diffusion of the interlayer H2O and Ca2+ is decelerated, attributed to Al-induced channel blocking and stronger interfacial adhesion with the calcium silicate layers. Mechanically, the Al-induced chain bridging enhances the load-bearing capacity of aluminosilicate chains along y direction, resulting in ∼ 57.1% and ∼ 100.4% enhancement of Young's modulus and tensile strength. In z direction, the cross-links provide ultra-strong connections between the layers by raising Young's modulus and strength by ∼ 4 and ∼ 6 times. This study provides profound guidance for future design of environmental-friendly cement with promising mechanical properties and durability. © 2023 Elsevier Ltd.

Research Area(s)

  • Atomic structure, Calcium aluminosilicate hydrate (CASH), Diffusive characteristics, Mechanical properties, Reinforcing mechanisms

Citation Format(s)