Whether so-called MgSi gels are produced under dolomite-quartz system under alkaline conditions

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research Pub Date : 2024-10-21 DOI:10.1016/j.cemconres.2024.107701

Xiaoming Song , Min Deng , Wei Li , Xianghui Lan , Mingshu Tang

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引用次数: 0

Abstract

Micro-crystalline to crypto-crystalline quartz exists always in dolomitic limestones. When the dolomitic limestones are used as aggregates of concrete, pore solutions mainly composed of K⁺, Na⁺, Ca²⁺ and OH⁻ ions may interacts simultaneously with dolomite and micro-crystalline to crypto-crystalline quartz. To understand mechanisms of alkali-silica-dolomite reactions in concrete, chemical reaction products in system of CaMg (CO₃)₂-SiO₂-Ca(OH)₂-KOH-NaOH-H₂O cured at 20 °C, 38 °C and 60 °C were analyzed by X-ray diffraction, infrared spectroscopy, differential scanning calorimeter-thermo gravity and scanning electron microscope. Results show that magnesium derived from dolomite was mainly incorporated in brucite and silicon derived from micro-crystalline to crypto-crystalline quartz was in alkali-silica gel. No evident magnesium silicate gels were detected under high alkaline condition. It is expected that magnesium silicate gels will not be formed accompanying with alkali-silica/dolomite reaction in concrete. Reaction in dolomite-quartz system is a superposition of ASR and ACR.

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在碱性条件下的白云石-石英体系中是否会产生所谓的镁硅凝胶

白云质灰岩中始终存在微晶到隐晶质石英。当白云质灰岩用作混凝土集料时，主要由 K+、Na+、Ca2+ 和 OH- 离子组成的孔隙溶液可能会同时与白云石和微晶到隐晶质石英发生作用。为了解混凝土中碱-二氧化硅-白云石反应的机理，采用 X 射线衍射、红外光谱、差示扫描量热仪-热重力和扫描电子显微镜分析了在 20 ℃、38 ℃ 和 60 ℃ 下养护的 CaMg (CO3)2-SiO2-Ca(OH)2-KOH-NaOH-H2O 系统中的化学反应产物。结果表明，来自白云石的镁主要结合在青金石中，而来自微晶到隐晶质石英的硅则结合在碱硅凝胶中。在高碱性条件下，没有检测到明显的硅酸镁凝胶。预计硅酸镁凝胶不会与混凝土中的碱硅石/白云石反应同时形成。白云石-石英系统中的反应是 ASR 和 ACR 的叠加。

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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.