Aluminum incorporation lowers the intrinsic mechanical properties of single-chain calcium silicate hydrate

IF 13.1 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research Pub Date : 2025-08-27 DOI:10.1016/j.cemconres.2025.108026

Jiawei Wang , Ruoxi Yang , Paula Sanz-Camacho , Mathieu Duttine , Thomas Huthwelker , Jiaqi Li

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引用次数: 0

Abstract

In blended cement systems, the principal hydration product is calcium (alumino) silicate hydrate (C-(A-)S-H). The investigation into how aluminum incorporation affects its mechanical properties is essential for optimizing the formulation and properties of cementitious materials. This study employs high-pressure X-ray diffraction to explore the intrinsic mechanical properties of nanocrystalline single-chain C-A-S-H (Ca-to-Si ratio 1.6), resembling chemical compositions of C-A-S-H in blended cement systems. Increasing aluminum incorporation softens all unit cell axes, with basal planar incompressibility governed by the aluminum coordination number, showing an increasing order of Al(IV) < Al(VI) < Al(V). The softening of the basal plane arises from the longer AlO bond length relative to SiO bond, and the different distortion indexes in AlO_x polyhedra. The hydrogen bond numbers and angles relative to the basal plane within per unit cell influence the basal planar incompressibility of single-chain C-A-S-H. Aluminum-uptake-induced expansion in basal space contributes to a softened c-axis.

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掺入铝降低了单链水合硅酸钙的内在力学性能

在混合水泥体系中，主要水化产物是水合硅酸钙（铝）（C-(A-)S-H）。研究铝掺入量对胶凝材料力学性能的影响，对优化胶凝材料的配方和性能具有重要意义。本研究采用高压x射线衍射研究了纳米晶单链C-A-S-H （ca - si比1.6）的内在力学性能，类似于混合水泥体系中C-A-S-H的化学成分。随着铝掺入量的增加，各单元胞轴均软化，基底平面不可压缩性受铝配位数的支配，表现为Al(IV) < Al(VI) < Al(V)。基面软化的原因是相对于SiO键，AlOx的键长较长，以及AlOx多面体的畸变指数不同。单链C-A-S-H的基面不可压缩性受单链C-A-S-H的氢键数和相对于基面角度的影响。基底空间的铝吸收引起的膨胀有助于软化c轴。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Cement and Concrete Research 工程技术-材料科学：综合

CiteScore

20.90

自引率

12.30%

发文量

318

审稿时长

53 days

期刊介绍： Cement and Concrete Research is dedicated to publishing top-notch research on the materials science and engineering of cement, cement composites, mortars, concrete, and related materials incorporating cement or other mineral binders. The journal prioritizes reporting significant findings in research on the properties and performance of cementitious materials. It also covers novel experimental techniques, the latest analytical and modeling methods, examination and diagnosis of actual cement and concrete structures, and the exploration of potential improvements in materials.