水玻璃模量和碱含量对碱激活热激活再生水泥性能的影响

IF 7.4 1区 工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY
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引用次数: 0

摘要

本研究利用机械活化、热活化和化学活化的协同效应制备再生水泥(RC),并揭示了水玻璃模量和碱含量对再生水泥的机械性能、水化特性和微观结构的影响机理,旨在解决因其反应活性低而导致的性能缺陷。根据初步实验结果,本研究重点关注热活化温度为 750°C 和 RC 替代率为 30% 的水泥砂浆。通过力学测试、X 射线衍射 (XRD)、汞侵入孔隙比拟 (MIP) 和扫描电子显微镜 (SEM),我们对碱活化剂含量对 RC 砂浆的力学性能、水化特性和微观结构的影响进行了一系列研究。试验结果表明,添加碱活化剂不会改变 RC 中水化产物的类型,但会改变水化反应速率和最终水化产物的数量。随着水玻璃模量和碱含量的增加,热活化 RC 中的石英和石膏含量降低,孔隙结构减少,无害孔隙体积增加,并产生更多的 C-(N)-A-S-H 凝胶。然而,当碱含量进一步增加时,热活化 RC 中的铝硅酸盐低聚物会溶解成铝分子和硅酸盐分子,从而降低砂浆中的低聚物含量,阻碍聚合过程。随着水玻璃模量和碱含量的增加,碱活化热活化 RC 的机械性能先上升后下降。当水玻璃模量为 1.5 和碱含量为 6 % 时,RC 的机械性能达到最佳,28 天抗压强度达到 33.97 兆帕,与未进行碱活化的 RC 相比提高了 23.04 %。此时,CH 和方解石参与高碱含量体系反应,形成 C-A-S-H 和 N-A-S-H 凝胶,导致 CH 几乎完全消耗,并在早期形成更致密的微观结构。我们的研究揭示了碱活化 RC 的水化反应机理和微观结构演变,优化了水玻璃模量和碱含量参数,为提高 RC 的力学性能提供了理论依据。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Influence of water glass modulus and alkali content on the properties of alkali-activated thermally activated recycled cement
This study utilizes the synergistic effects of mechanical activation, thermal activation, and chemical activation to prepare recycled cement (RC) and reveals the mechanism by which water glass modulus and alkali content affect the mechanical properties, hydration characteristics, and microstructure of RC, aiming to address the performance deficiencies caused by its low reactivity. Based on preliminary experimental results, this study focuses on cement mortars with a thermal activation temperature of 750°C and an RC replacement rate of 30 %. Through mechanical tests, X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM), we conducted a series of investigations into the influence of alkali activator content on the mechanical properties, hydration characteristics, and microstructure of RC mortars. The test results show that adding an alkali activator does not alter the types of hydration products in RC; it can change the hydration reaction rate and the quantity of final hydration products. As the water glass modulus and alkali content increase, the quartz and gypsum content in the thermally activated RC decrease, the pore structure reduces, the volume of harmless pores increases, and more C-(N)-A-S-H gel is produced. However, when alkali content further increases, the aluminosilicate oligomers in the thermally activated RC dissolve into aluminum and silicate molecules, reducing the oligomer content in the mortar and hindering the polymerization process. The mechanical properties of the alkali-activated thermally activated RC first increase and then decrease with the rise in water glass modulus and alkali content. The optimal mechanical performance of RC is achieved when the water glass modulus is 1.5 and alkali content is 6 %, with a 28-day compressive strength reaching 33.97 MPa, an improvement of 23.04 % compared to RC without alkali activation. At this point, CH and calcite participate in the high-alkali content system reaction, forming C-A-S-H and N-A-S-H gels, leading to a near-complete consumption of CH and the formation of a denser microstructure at early stages. Our study reveals the hydration reaction mechanism and microstructural evolution of alkali-activated RC, optimizing the parameters of water glass modulus and alkali content and providing a theoretical basis for improving the mechanical properties of RC.
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来源期刊
Construction and Building Materials
Construction and Building Materials 工程技术-材料科学:综合
CiteScore
13.80
自引率
21.60%
发文量
3632
审稿时长
82 days
期刊介绍: Construction and Building Materials offers an international platform for sharing innovative and original research and development in the realm of construction and building materials, along with their practical applications in new projects and repair practices. The journal publishes a diverse array of pioneering research and application papers, detailing laboratory investigations and, to a limited extent, numerical analyses or reports on full-scale projects. Multi-part papers are discouraged. Additionally, Construction and Building Materials features comprehensive case studies and insightful review articles that contribute to new insights in the field. Our focus is on papers related to construction materials, excluding those on structural engineering, geotechnics, and unbound highway layers. Covered materials and technologies encompass cement, concrete reinforcement, bricks and mortars, additives, corrosion technology, ceramics, timber, steel, polymers, glass fibers, recycled materials, bamboo, rammed earth, non-conventional building materials, bituminous materials, and applications in railway materials.
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