Cement and Concrete Research最新文献

英文中文

Detailed characterisation of hemp and hempcrete pore structures: Effects on thermal and acoustic properties 大麻和大麻混凝土孔隙结构的详细特征：对热性能和声学性能的影响

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

Cement and Concrete Research

Pub Date : 2024-10-28 DOI: 10.1016/j.cemconres.2024.107702

Haemin Song , Taehwan Kim , Ailar Hajimohammadi , Jae Eun Oh , Arnaud Castel

Lightweight porous composites have been widely explored to improve their acoustic and thermal performances. Hempcrete can serve as thermal insulating or soundproofing material by utilising its high porosity. However, the rigorous correlation between hempcrete thermal and acoustic performance and its pore structure remains poorly understood due to its different pore types. In this study, three hempcrete pore types [i.e., i) inter-pore between hemp and mortar, ii) hemp intra-pore, and iii) mortar intra-pore] were modified by tamping, delignification, and foaming agent conditions, respectively. Then the volumes of three types of pores were estimated using X-ray micro-computed tomography (μCT) and mercury intrusion porosimetry. The new segmentation methods were developed and their reliability and accuracy were validated. Then, the pore volumes were correlated to the thermal and acoustic properties of hempcrete. Low tamping and high delignification conditions are recommended to increase inter-pore volume and enhance hempcrete performances relating to both thermal insulation and sound absorption for real-world hempcrete applications.

为改善轻质多孔复合材料的隔音和隔热性能，人们对其进行了广泛的研究。大麻混凝土可利用其高孔隙率作为隔热或隔音材料。然而，由于麻混凝土的孔隙类型不同，人们对其热性能和隔音性能与其孔隙结构之间的密切联系仍然知之甚少。在本研究中，分别通过捣实、脱木质素和发泡剂条件改变了三种麻混凝土孔隙类型[即：i) 麻与砂浆之间的孔隙；ii) 麻内部孔隙；iii) 砂浆内部孔隙]。然后使用 X 射线显微计算机断层扫描（μCT）和汞侵入孔隙测定法估算了三种孔隙的体积。开发了新的细分方法，并验证了其可靠性和准确性。然后，将孔隙体积与麻混凝土的热学和声学特性相关联。建议在低振捣和高脱木质素条件下增加孔隙间容积，提高麻混凝土在实际应用中的隔热和吸音性能。

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引用次数: 0

Thermodynamic modeling of alkali-activated fly ash paste 碱激活粉煤灰糊的热力学模型

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

Cement and Concrete Research

Pub Date : 2024-10-22 DOI: 10.1016/j.cemconres.2024.107699

Yun Chen , Bin Ma , Jiayi Chen , Zhenming Li , Xuhui Liang , Luiz Miranda de Lima , Chen Liu , Suhong Yin , Qijun Yu , Barbara Lothenbach , Guang Ye

Previously, the lack of a thermodynamic database for N-(C-)A-S-H gel limited the application of thermodynamic modeling to alkali-activated fly ash (AAFA). This study pioneers thermodynamic modeling of AAFA using a recently developed thermodynamic dataset for N-(C-)A-S-H gel. The reaction products, pore solutions and reaction kinetics of AAFA pastes were experimentally determined. Based on the reaction kinetics, the composition of the solid phases and the pore solution of AAFA were modeled over time. The results showed that the simulated compositions of the solid reaction products and pore solution match closely with the experimental results, especially for the sodium hydroxide-activated system. Moreover, modeling results point out the potential presence of minor reaction products (e.g., C-(N-)A-S-H gel, microcrystalline ferrihydrite, Mg-containing phases) undetectable by experimental techniques. The study also demonstrated that thermodynamic modeling accurately captured the amount of bound water in reaction products, highlighting its robustness in both qualitative and quantitative analysis.

以前，由于缺乏 N-(C-)A-S-H凝胶的热力学数据库，限制了碱激活粉煤灰（AAFA）热力学模型的应用。本研究利用最新开发的 N-(C-)A-S-H凝胶热力学数据集，率先对 AAFA 进行了热力学建模。实验测定了 AAFA 浆料的反应产物、孔溶液和反应动力学。根据反应动力学，建立了 AAFA 固相和孔溶液随时间变化的组成模型。结果表明，模拟的固体反应产物和孔溶液成分与实验结果非常吻合，尤其是氢氧化钠活化体系。此外，建模结果还指出了实验技术无法检测到的次要反应产物（如 C-(N-)A-S-H 凝胶、微晶铁水物、含镁相）的潜在存在。研究还表明，热力学建模能准确捕捉反应产物中的结合水量，突出了其在定性和定量分析中的稳健性。

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引用次数: 0

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

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

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.

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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引用次数: 0

Understanding nanoscale mechanism of compression casting on rubber-cement interface: A molecular dynamics study 了解橡胶-水泥界面压缩铸造的纳米尺度机理：分子动力学研究

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

Cement and Concrete Research

Pub Date : 2024-10-18 DOI: 10.1016/j.cemconres.2024.107700

Juntao Kang, Kai Wang, Yugui Cao, Lei Wang, Xingxiang Chen, Tianyue Wu, Zechuan Yu

Using rubber particles as concrete aggregate can effectively address the issue of “black pollution” caused by waste tires. Although the inclusion of rubber particles reduces concrete strength, a compression casting method can enhance its mechanical properties, offering a novel approach to expanding the application range of rubber-concrete. Further development of the compression casting method requires an in-depth understanding of the mechanism behind the novel technique. This study focuses on the nanoscale mechanism of the compression casting, via all-atom molecular dynamics simulations of a C-S-H/rubber interface. Surface roughness is introduced to the employed C-S-H model, providing a more realistic representation of the cement surface compared to existing studies. Models subjected to various levels of compression casting are prepared and tested. Interface integrity is found to be significantly improved with sufficient pre-compression. When the pre-compression force increases from 100 atm to 4000 atm, the peak pullout force of the C-S-H/rubber interface transition zone increases by 90.26%, and the interfacial bond energy increase by 56.65% to 2.27 J/m². Lastly, a novel pre-compression method for rubber-concrete aggregate is proposed to enhance its economic and engineering applicability. This study reports an in-depth investigation on compression casting mechanisms and contributes to advancement of compression casting methods.

使用橡胶颗粒作为混凝土骨料可有效解决废轮胎造成的 "黑色污染 "问题。虽然橡胶颗粒的加入会降低混凝土强度，但压缩浇注法可以提高其机械性能，为扩大橡胶混凝土的应用范围提供了一种新方法。压缩浇注法的进一步发展需要深入了解这项新技术背后的机理。本研究通过对 C-S-H/橡胶界面的全原子分子动力学模拟，重点研究了压缩浇注的纳米级机理。采用的 C-S-H 模型引入了表面粗糙度，与现有研究相比，更真实地再现了水泥表面。对模型进行了不同程度的压缩浇注和测试。通过充分的预压缩，界面完整性得到明显改善。当预压缩力从 100 atm 增加到 4000 atm 时，C-S-H/橡胶界面过渡区的峰值拉拔力增加了 90.26%，界面结合能增加了 56.65%，达到 2.27 J/m2。最后，提出了一种新型的橡胶混凝土骨料预压缩方法，以提高其经济性和工程适用性。本研究报告深入探讨了压缩浇注机理，有助于推动压缩浇注方法的发展。

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引用次数: 0

Full-scale observation of drying-induced microstructure change in hardened cement paste by water and 2-propanol 1H NMR relaxometry 通过水和 2-丙醇 1H NMR 驰豫测定法全面观察硬化水泥浆中由干燥引起的微观结构变化

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

Cement and Concrete Research

Pub Date : 2024-10-18 DOI: 10.1016/j.cemconres.2024.107698

Ryusei Igami , Go Igarashi , Abudushalamu Aili , Ryo Kurihara , Takahiro Ohkubo , Ippei Maruyama

To understand the microstructural changes in the hardened cement paste during the drying, hardened white Portland cement pastes were D-dried or dried under 11, 33, 40, and 75% relative humidity, and then, pastes were impregnated with 2-propanol or water under vacuum. Measurement of ¹H NMR relaxometry was employed for the pastes before and after impregnation, and the full-scale microstructural changes of the hardened cement paste after drying were successfully visualized. It was observed that the volume of the coarse pores outside the agglomeration of calcium-silicate-hydrate (C-S-H) increased, and the volume of the C-S-H interlayer spaces and gel pores decreased as the drying relative humidity decreased. Thus, it was evidenced that interlayer space is decreasing during drying. It was also confirmed that 2-propanol can enter some of the interlayer space of C-S-H after harsh drying.

为了了解硬化水泥浆体在干燥过程中的微观结构变化，将硬化的白色硅酸盐水泥浆体在 11%、33%、40% 和 75% 的相对湿度下进行 D 干燥或干燥，然后在真空条件下用 2-丙醇或水浸渍浆体。对浸渍前后的水泥浆进行了 1H NMR 驰豫测定，成功地观察到了干燥后硬化水泥浆的全面微观结构变化。结果表明，随着干燥相对湿度的降低，硅酸钙水合物（C-S-H）团聚外的粗孔隙体积增大，而 C-S-H 层间空隙和凝胶孔隙体积减小。因此，这证明了层间空间在干燥过程中不断减小。研究还证实，2-丙醇在苛刻干燥后可进入 C-S-H 的部分层间空间。

引用次数: 0

Investigation of the AFm-Cl system: Fe-to-Al solid solution, thermal behavior and carbonation AFm-Cl 系统研究：铁-铝固溶体、热行为和碳化

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

Cement and Concrete Research

Pub Date : 2024-10-15 DOI: 10.1016/j.cemconres.2024.107696

Aurore Lechevallier , Mohend Chaouche , Jérôme Soudier , Evelyne Prat , Guillaume Renaudin

Due to increasing interest in reducing CO₂ emissions, new hydraulic binders are emerging, many of which contain significant amounts of iron and aluminum oxides. The reactivity of such binders can be activated using CaCl₂. It thus appears essential to investigate mixed Al/Fe-Cl hydrates to better characterize the hydration products and hydration processes of these new hydraulic binders. AFm-Cl phases with varying proportions of Al³⁺ and Fe³⁺ trivalent cations were synthesized and characterized. Carbonation of AFm-Cl samples is unavoidable at ambient atmosphere and leads to phases with Ca₂Al_1-xFe_x(OH)₆·Cl_0.7(CO₃)_0.15·2H₂O general composition (samples were synthesized for x = 0, 0.17, 0.33, 0.50, 0.67, 0.83 and 1). A complete solid solution between the two Ca₂Al(OH)₆·Cl_0.7(CO₃)_0.15·2H₂O and Ca₂Fe(OH)₆·Cl_0.7(CO₃)_0.15·2H₂O endmembers was demonstrated. Two hydration states were identified with characteristic interlayer distances of about 7.8 Å and 6.8 Å for, respectively, the Ca₂Al_1-xFe_x(OH)₆·Cl_0.7(CO₃)_0.15·2H₂O hydrate and the Ca₂Al_1-xFe_x(OH)₆·Cl_0.7(CO₃)_0.15 dehydrated phase. Thermal studies indicated a similar succession of thermal events for Ca₂Al_1-xFe_x(OH)₆·Cl_0.7(CO₃)_0.15·2H₂O regardless of the nature of the trivalent cation; the presence of iron however decreasing the degradation temperatures. Finally, the Ca₂Al_1-xFe_x(OH)₆·Cl_0.7(CO₃)_0.15·2H₂O phase was investigated in the presence of carbonate anions, showing a progressive exchange of chloride for carbonate within the interlayer to form Ca₂Al_1-xFe_x(OH)₆·(CO₃)_0.5·3H₂O before degrading into calcite.

由于人们对减少二氧化碳排放的兴趣与日俱增，新型液压粘合剂不断涌现，其中许多都含有大量的铁和铝氧化物。使用 CaCl2 可以激活此类粘合剂的反应活性。因此，研究 Al/Fe-Cl 混合水合物以更好地描述这些新型液压粘合剂的水化产物和水化过程显得至关重要。我们合成并表征了具有不同比例 Al3+ 和 Fe3+ 三价阳离子的 AFm-Cl 相。AFm-Cl 样品在环境气氛中不可避免地会发生碳化，从而形成具有 Ca2Al1-xFex(OH)6-Cl0.7(CO3)0.15-2H2O 基本成分的阶段（合成了 x = 0、0.17、0.33、0.50、0.67、0.83 和 1 的样品）。结果表明，Ca2Al(OH)6-Cl0.7(CO3)0.15-2H2O 和 Ca2Fe(OH)6-Cl0.7(CO3)0.15-2H2O 两种内含物之间存在完整的固溶体。确定了两种水合状态，Ca2Al1-xFex(OH)6-Cl0.7(CO3)0.15-2H2O 水合物和 Ca2Al1-xFex(OH)6-Cl0.7(CO3)0.15 脱水相的特征层间距离分别约为 7.8 Å 和 6.8 Å。热研究表明，无论三价阳离子的性质如何，Ca2Al1-xFex(OH)6-Cl0.7(CO3)0.15-2H2O 都会发生类似的连续热事件；但铁的存在会降低降解温度。最后，在碳酸根阴离子存在的情况下对 Ca2Al1-xFex(OH)6-Cl0.7(CO3)0.15-2H2O 相进行了研究，结果表明在降解为方解石之前，氯离子在层间逐渐交换为碳酸盐，形成 Ca2Al1-xFex(OH)6-(CO3)0.5-3H2O。

{"title":"Investigation of the AFm-Cl system: Fe-to-Al solid solution, thermal behavior and carbonation","authors":"Aurore Lechevallier , Mohend Chaouche , Jérôme Soudier , Evelyne Prat , Guillaume Renaudin","doi":"10.1016/j.cemconres.2024.107696","DOIUrl":"10.1016/j.cemconres.2024.107696","url":null,"abstract":"<div><div>Due to increasing interest in reducing CO2 emissions, new hydraulic binders are emerging, many of which contain significant amounts of iron and aluminum oxides. The reactivity of such binders can be activated using CaCl2. It thus appears essential to investigate mixed Al/Fe-Cl hydrates to better characterize the hydration products and hydration processes of these new hydraulic binders. AFm-Cl phases with varying proportions of Al3+ and Fe3+ trivalent cations were synthesized and characterized. Carbonation of AFm-Cl samples is unavoidable at ambient atmosphere and leads to phases with Ca2Al1-xFex(OH)6·Cl0.7(CO3)0.15·2H2O general composition (samples were synthesized for x = 0, 0.17, 0.33, 0.50, 0.67, 0.83 and 1). A complete solid solution between the two Ca2Al(OH)6·Cl0.7(CO3)0.15·2H2O and Ca2Fe(OH)6·Cl0.7(CO3)0.15·2H2O endmembers was demonstrated. Two hydration states were identified with characteristic interlayer distances of about 7.8 Å and 6.8 Å for, respectively, the Ca2Al1-xFex(OH)6·Cl0.7(CO3)0.15·2H2O hydrate and the Ca2Al1-xFex(OH)6·Cl0.7(CO3)0.15 dehydrated phase. Thermal studies indicated a similar succession of thermal events for Ca2Al1-xFex(OH)6·Cl0.7(CO3)0.15·2H2O regardless of the nature of the trivalent cation; the presence of iron however decreasing the degradation temperatures. Finally, the Ca2Al1-xFex(OH)6·Cl0.7(CO3)0.15·2H2O phase was investigated in the presence of carbonate anions, showing a progressive exchange of chloride for carbonate within the interlayer to form Ca2Al1-xFex(OH)6·(CO3)0.5·3H2O before degrading into calcite.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"186 ","pages":"Article 107696"},"PeriodicalIF":10.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Revealing the connection between carbonation regimes and early pozzolanic reactivity of recycled concrete powder: Impact of composition and microstructure 揭示再生混凝土粉末碳化机制与早期胶凝反应性之间的联系：成分和微观结构的影响

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

Cement and Concrete Research

Pub Date : 2024-10-13 DOI: 10.1016/j.cemconres.2024.107697

Zihan Ma , Yi Jiang , Jionghuang He , Peiliang Shen , Qinglong Qin , Zhenjiang Gu , Jiangshan Li , Chi Sun Poon

This study aims to establish relationship between carbonation regimes and the early pozzolanic reactivity of carbonated recycled concrete powder (CRCP) by comparing the composition, structure and surface properties of the carbonation products. The surface of dry CRCP was characterized by a silica-rich layer and contains low-polymerized silica phases along with over 18 % of unstable calcium carbonate (Cc). Wet CRCP exhibits a silica-rich surface with the highest degree of silica polymerization and stable calcite in its composition. Semi-dry CRCP has a calcium-rich surface also contains high silica polymerization and over 29 % unstable calcium carbonate, and the highest specific surface area, leading to the fastest silicon dissolution and calcium consumption during pozzolanic reactions. The early pozzolanic reaction kinetics in semi-dry and wet carbonation are limited by the dissolution of carbonation products, whereas dry carbonation does not exhibit this limitation. Understanding this connection is crucial for selecting optimal carbonation techniques to enhance waste concrete utilization.

本研究旨在通过比较碳化产物的组成、结构和表面特性，确定碳化机制与碳化再生混凝土粉（CRCP）早期胶凝反应性之间的关系。干法 CRCP 的表面特征是富含二氧化硅层，含有低聚合二氧化硅相和超过 18% 的不稳定碳酸钙 (Cc)。湿润的 CRCP 表面富含二氧化硅，二氧化硅聚合度最高，成分中含有稳定的方解石。半干的 CRCP 表面富含钙质，也含有较高的二氧化硅聚合度和 29% 以上的不稳定碳酸钙，比表面积最大，因此在水胶凝反应过程中硅的溶解和钙的消耗速度最快。半干法和湿法碳化的早期水胶凝反应动力学受到碳化产物溶解的限制，而干法碳化则没有这种限制。了解这种联系对于选择最佳碳化技术以提高废弃混凝土利用率至关重要。

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引用次数: 0

The Cement and Concrete Research Le Chatelier Awards 水泥与混凝土研究勒沙特里耶奖

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

Cement and Concrete Research

Pub Date : 2024-10-12 DOI: 10.1016/j.cemconres.2024.107689

Robert J. Flatt

引用次数: 0

Quantifying the immobilization mechanisms of heavy metals by Calcium Silicate Hydrate (C-S-H): The case of Cu2+ 量化硅酸钙水合物（C-S-H）固定重金属的机制：以 Cu2+ 为例

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

Cement and Concrete Research

Pub Date : 2024-10-10 DOI: 10.1016/j.cemconres.2024.107695

Qi Liu , Pan Feng , Lijing Shao , Chen Chen , Xin Liu , Yuefeng Ma , Lizhi Zhang , Guoqing Geng

Understanding the interactions between calcium silicate hydrate (C-S-H) and heavy metals is vital for optimizing the use of solid waste in cementitious materials. This paper introduces an innovative approach to elucidate the immobilization mechanism of Cu²⁺, a representative heavy metal. The roles of Ca²⁺ and OH⁻ in Cu²⁺ immobilization were comprehensively investigated through being treated by C-S-H samples with varying interlayer Ca²⁺ contents via meticulous immersion in ammonium chloride (NH₄Cl). Our results indicate that Cu²⁺ immobilization primarily occurs via complete substitution of interlayer Ca²⁺ and partial substitution of intralayer Ca²⁺, with contributions of 40 % and 59 %, respectively, for a Ca/Si ratio of 1.2. Minor mechanisms like OH⁻ complexation and surface adsorption account for the remaining immobilization. The formation of Si-O-Cu complexes was confirmed by X-ray photoelectron (XPS) and Extended X-ray Absorption Fine Structure (EXAFS) analysis. This study provides a quantitative methodology that informs strategies for sustainable cementitious waste utilization.

了解水合硅酸钙（C-S-H）与重金属之间的相互作用对于优化水泥基材料中固体废弃物的利用至关重要。本文介绍了一种创新方法来阐明具有代表性的重金属 Cu2+ 的固定化机理。通过将不同层间 Ca2+ 含量的 C-S-H 样品精心浸泡在氯化铵（NH4Cl）中，全面研究了 Ca2+ 和 OH- 在 Cu2+ 固定化过程中的作用。我们的研究结果表明，Cu2+ 固定化主要是通过层间 Ca2+ 的完全置换和层内 Ca2+ 的部分置换实现的，在 Ca/Si 比为 1.2 时，两者的贡献率分别为 40% 和 59%。其余的固定化作用主要来自于一些次要机制，如羟基络合和表面吸附。X 射线光电子（XPS）和扩展 X 射线吸收精细结构（EXAFS）分析证实了 Si-O-Cu 复合物的形成。这项研究提供了一种定量方法，为水泥基废物的可持续利用战略提供了依据。

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引用次数: 0

Setting reaction of a olivine-based Mg-phosphate cement 橄榄石基磷酸镁水泥的凝结反应

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

Cement and Concrete Research

Pub Date : 2024-10-10 DOI: 10.1016/j.cemconres.2024.107694

Davide Bernasconi , Alberto Viani , Lucie Zárybnická , Simone Bordignon , Jose R.A. Godinho , Alexey Maximenko , Cem Celikutku , Sadaf Fatima Jafri , Elisa Borfecchia , Quentin Wehrung , Roberto Gobetto , Alessandro Pavese

The cementitious properties of natural Mg-rich olivine when reacted with a phosphoric acid solution are investigated, as a function of acid concentration and liquid/solid mass ratio. The obtained cements are composed of residual olivine crystals and amorphous silica nanoparticles dispersed in a dense and compact newberyite (MgHPO₄∙3H₂O) matrix. The latter was mostly formed by packed micrometric tabular crystals, although evidence of the presence of a fraction of amorphous MgHPO₄ was also found. Water content in the raw mix was observed to play a pivotal role on the reaction pathway, either promoting porosity or hindering the crystallization of the products. Up to 57 % of olivine reactivity, whose dissolution was promoted by the curing temperature (60 °C) and low pH, was achieved. All in all, these results indicate that the industrial mineral olivine may serve a viable source of Mg for the production of phosphate cements.

研究了天然富镁橄榄石与磷酸溶液反应时的胶结特性，以及酸浓度和液体/固体质量比的函数关系。所获得的胶结物由残余橄榄石晶体和无定形二氧化硅纳米颗粒组成，它们分散在致密紧密的新贝里岩（MgHPO4∙3H2O）基体中。后者主要由堆积的微米级片状晶体形成，但也发现了部分无定形 MgHPO4 的存在。据观察，原料混合物中的水含量对反应路径起着关键作用，既可促进孔隙度，也可阻碍产物结晶。由于固化温度（60 °C）和低 pH 值促进了橄榄石的溶解，因此橄榄石的反应活性高达 57%。总之，这些结果表明，工业矿物橄榄石可作为生产磷酸盐水泥的可行镁源。

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引用次数: 0

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