Cement & concrete composites最新文献_第9页

A robust and predictive three-dimensional (3D) finite element (FE) model for evaluating the pullout behavior of steel fibers from a cementitious matrix 一个鲁棒和预测的三维（3D）有限元（FE）模型，用于评估钢纤维从胶凝基质中的拔出行为

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

Cement & concrete composites

Pub Date : 2025-11-21 DOI: 10.1016/j.cemconcomp.2025.106410

Wei-He Liu, Tao Yu

Despite the extensive experimental and theoretical investigations on the pullout behavior of steel fibers from fiber-reinforced cementitious composites (FRCCs), the effects of the fiber clamping condition on the pullout behavior remain unclear. There is also a lack of rational assessment of the existing methods for evaluating the pullout behavior of steel fibers in FRCCs. This paper presents a simple, robust and predictive three-dimensional (3D) finite element (FE) model for elucidating these issues. Particularly, a modified Mohr-Coulomb (MMC) model was proposed to describe concrete spalling. A simple three-parameter cohesive-friction model was proposed to describe the fiber/matrix interfacial behavior. Having a low sensitivity to mesh size and a high meshing flexibility, the proposed FE model was computationally efficient. The robustness of the FE model was demonstrated by reproducing the experimental results from the literature covering both single-sided and double-sided pullout tests with a wide range of matrix strengths, fiber diameters and yield strengths, using only three physical fitting parameters (i.e., friction coefficient, confining pressure and cohesive strength). The numerical simulations showed that single-sided pullout tests overestimated the bond strength due to the unrealistic rigid-clamping conditions. Two-sided pullout tests with unequal fiber embedment lengths were preferable for resembling the action of fibers in cracked FRCCs. Traditional micromechanical models inappropriately evaluated the snubbing effect, as they predicted overly stiff bridging stress-crack opening (

σ_{B} - w

) curves and overestimated the peak stress. A novel analytical model was proposed which provided comparably accurate predictions of the

σ_{B} - w

curve with the FE simulations of two-sided pullout tests.

尽管对纤维增强胶凝复合材料（FRCCs）中钢纤维的拉拔行为进行了大量的实验和理论研究，但纤维夹紧条件对拉拔行为的影响尚不清楚。现有的评价钢纤维在frp混凝土中的拉拔性能的方法也缺乏合理的评价。本文提出了一个简单、鲁棒和可预测的三维（3D）有限元（FE）模型来阐明这些问题。特别提出了一种改进的Mohr-Coulomb （MMC）模型来描述混凝土剥落。提出了一种简单的三参数黏结摩擦模型来描述纤维/基体界面行为。该模型对网格尺寸的敏感性低，网格划分灵活性高，计算效率高。通过再现文献中涵盖单面和双面拉拔试验的实验结果，证明了有限元模型的稳健性，该试验具有广泛的基体强度、纤维直径和屈服强度，仅使用三个物理拟合参数（即摩擦系数、围压和内聚强度）。数值模拟结果表明，由于不现实的刚性夹紧条件，单侧拉拔试验高估了粘结强度。不均匀纤维埋置长度的双侧拉拔试验可以较好地模拟纤维在开裂纤维混凝土中的作用。传统的微力学模型预测的桥接应力-裂纹张开（σB−w）曲线过硬，峰值应力估计过高，对缓压效应评价不合理。提出了一种新的解析模型，通过双侧拉拔试验的有限元模拟，对σB−w曲线进行了较为准确的预测。

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引用次数: 0

Decoupling early-age free shrinkage and restraint effects in 3D printed concrete using digital image correlation 利用数字图像相关技术解耦3D打印混凝土的早期自由收缩和约束效应

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

Cement & concrete composites

Pub Date : 2025-11-20 DOI: 10.1016/j.cemconcomp.2025.106405

Aniket Kumar Patel , Avinaya Tripathi , Ravi Kiran , Manu Santhanam , Gaurav Sant , Narayanan Neithalath

3D printed concrete (3DPC) undergoes substantial early-age shrinkage and cracking, driven by its formwork-free nature and high surface area-to-volume ratio that accelerates moisture loss. Measuring early-age deformations in 3DPC is complex because of the local heterogeneity caused by layering variations, overburden effects, print geometry, and the restraint effects that result in non-uniform volume changes. This paper utilizes Digital Image Correlation (DIC) to capture early-age (first 24 h) shrinkage deformations in 3D printed elements made using different binders, and with different layer and filament configurations. DIC-based surface strain measurements accurately capture the rapid volume change due to early drying, and the gradual plateauing as the mixture sets and hardens. The differences in restraint effects—both from the substrate as well as the layers and filaments—impose substantial differences in measured shrinkage. Hence, a novel framework is proposed here to quantify the multi-directional restraint effects, and to decouple them from the measured shrinkage. The result is the extraction of free shrinkage strains (geometry- and restraint independent) in 3DPC that is a function of the mixture design and exposure condition. The framework is validated for multiple layers and filaments with different dimensions as well. The approach, in conjunction with measurements of time-dependent elastic modulus, also allows for the determination of tensile stresses and thus the cracking propensity in in-place 3D printed concrete elements.

3D打印混凝土（3DPC）由于其无模板的特性和高表面积体积比，加速了水分的流失，因此会经历大量的早期收缩和开裂。由于层状变化、覆盖层效应、打印几何形状和约束效应导致体积变化不均匀，导致局部非均匀性，因此测量3DPC的早期变形非常复杂。本文利用数字图像相关（DIC）来捕捉使用不同粘合剂、不同层和长丝配置的3D打印元件的早期（前24小时）收缩变形。基于dic的表面应变测量准确地捕捉到由于早期干燥引起的快速体积变化，以及随着混合物凝固和硬化而逐渐趋于稳定。约束效应的差异——既来自基材，也来自层和细丝——造成了测量收缩率的巨大差异。因此，本文提出了一种新的框架来量化多向约束效应，并将它们与测量的收缩解耦。结果是在3DPC中提取自由收缩应变（几何和约束无关），这是混合物设计和暴露条件的函数。该框架也适用于不同尺寸的多层和细丝。该方法与时间相关弹性模量的测量相结合，还可以确定现场3D打印混凝土构件的拉伸应力，从而确定开裂倾向。

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引用次数: 0

Layered double hydroxides-based binders: Performance, reaction mechanism, and thermodynamic modelling 层状双羟基基粘合剂：性能、反应机理和热力学模型

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

Cement & concrete composites

Pub Date : 2025-11-19 DOI: 10.1016/j.cemconcomp.2025.106400

Hamdy A. Abdel-Gawwad , Tamino Hirsch , Christian Lehmann , Dietmar Stephan

The commercial viability of alkali-activated materials remains fundamentally constrained by the high variability and limited availability of traditional aluminosilicate precursors. Addressing this critical barrier requires the utilization of widely accessible, consistent feedstocks. Herein, we report the development of a novel layered double hydroxide (LDH)-based binder utilizing limestone powder (LP) as the primary precursor. This study presents the first systematic, year-long comparative investigation of binders incorporating monocarboaluminate (MCA-LDH) versus hydrotalcite (HT-LDH). An LP activated with sodium aluminate (NaAlO₂) solution produced an MCA-LDH binder with compressive strengths ranging from 23 to 78 MPa after one year, depending on the alkali dosage. Crucially, the substitution of 30 vol% of LP with reactive magnesia fundamentally altered the phase assemblage, suppressing MCA-LDH formation and promoting the development of the stable HT-LDH phase, a finding consistent with thermodynamic predictions and microstructural analysis. The long-term performance data reveal significant structural degradation in the MCA-LDH crystalline lattice over time, contrasting sharply with the superior stability of HT-LDH. It was found that the formation of pirssonite (Na₂CO₃⋅CaCO₃⋅2H₂O) is the primary mechanism driving the detrimental decrease in water availability and subsequent MCA-LDH crystalline deformation. This work, supported by integrated thermodynamic modeling, establishes a robust theoretical framework for elucidating the long-term phase transformation kinetics, and provides essential guidance for the design of durable LP-based alkali-activated systems.

碱活化材料的商业可行性仍然从根本上受到传统铝硅酸盐前体的高可变性和有限可用性的限制。解决这一关键障碍需要利用广泛可及的一致原料。在此，我们报告了一种新的层状双氢氧化物（LDH）基粘合剂的发展，以石灰石粉末（LP）为主要前驱体。本研究首次对单碳铝酸盐（MCA-LDH）与水滑石（HT-LDH）结合剂进行了为期一年的系统比较研究。用铝酸钠（NaAlO2）溶液活化的LP，一年后产生的MCA-LDH粘合剂的抗压强度在23至78 MPa之间，取决于碱的用量。最重要的是，用活性氧化镁取代30 vol%的LP从根本上改变了相组合，抑制了MCA-LDH的形成，促进了稳定HT-LDH相的发展，这一发现与热力学预测和微观结构分析相一致。长期性能数据显示，随着时间的推移，MCA-LDH晶格的结构明显退化，与HT-LDH的优越稳定性形成鲜明对比。结果表明，单晶石（Na2CO3⋅CaCO3⋅2H2O）的形成是导致水有效性降低和MCA-LDH晶体变形的主要机制。这项工作在综合热力学模型的支持下，为阐明长期相变动力学建立了一个强大的理论框架，并为设计耐用的基于lp的碱活化体系提供了必要的指导。

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引用次数: 0

Statistical design and mechanism analysis of cement-based composites as cathodes in seawater dissolved oxygen batteries 海水溶解氧电池用水泥基复合材料阴极的统计设计及机理分析

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

Cement & concrete composites

Pub Date : 2025-11-19 DOI: 10.1016/j.cemconcomp.2025.106401

Jun Xu , Banghui Chen , Chuanqing Fu , Wei She

Efficient utilization of marine resources is pivotal in addressing the growing challenges of energy shortages within marine infrastructure. This study represents the first investigation into the application of cement-based composite materials as cathode electrodes in seawater dissolved oxygen batteries. A six-factor, five-level orthogonal design was employed to systematically explore the synergistic effects of various factors, including carbon materials, catalyst types, water-to-cement ratio, carbon-to-cement ratio, catalyst content, and corrosion inhibitors. The TOPSIS-EWM multi-criteria evaluation method was utilized to identify the optimal formulation from 25 potential combinations, with the top-performing samples being: graphite powder/cement = 0.20, activated carbon/cement = 0.04, w/c = 0.60. The study reveals a complex coupling between the cathode material's microstructure and its macroscopic performance, encompassing electrochemical characteristics, dissolved oxygen adsorption capacity, corrosion resistance, and mechanical strength. These findings provide a solid theoretical foundation and practical engineering solutions for the integration of cement-based cathode materials in marine energy storage systems.

有效利用海洋资源是解决海洋基础设施日益严峻的能源短缺挑战的关键。本研究首次探索了水泥基复合材料作为海水溶解氧电池阴极电极的应用。采用六因素五水平正交设计，系统探讨了碳材料、催化剂类型、水灰比、碳灰比、催化剂含量、缓蚀剂等因素的协同效应。采用TOPSIS-EWM多准则评价法从25个潜在组合中筛选出最佳配方，最佳组合为石墨粉/水泥= 0.20，活性炭/水泥= 0.04,w/c = 0.60。该研究揭示了阴极材料的微观结构与其宏观性能之间的复杂耦合，包括电化学特性、溶解氧吸附能力、耐腐蚀性和机械强度。这些研究结果为水泥基正极材料在海洋储能系统中的集成提供了坚实的理论基础和实际工程解决方案。

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引用次数: 0

Roles of biochar in improving carbon mineralisation and sequestration in sustainable cement–based materials 生物炭在改善可持续水泥基材料中碳矿化和固存中的作用

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

Cement & concrete composites

Pub Date : 2025-11-19 DOI: 10.1016/j.cemconcomp.2025.106403

Zhaocheng Li , Zhiyu Luo , Wenkui Dong , Fulin Qu , Kejing Wang , Daniel C.W. Tsang , Wengui Li

Biochar (BC) can enhance the carbon sequestration capacity of cementitious composites, offering a promising strategy for reducing carbon emissions. This study reviews the effects of BC on the carbon sequestration capacity of biochar–cement composites (BCC) from a microstructural perspective. Firstly, the effects of biomass type, pyrolysis conditions, and activation methods on the physicochemical properties of BC are discussed. Then, the effects of various types of BC on the hydration and carbonation reactions of cementitious matrices are summarised through micro-characterisation techniques. Moreover, BC significantly affects fresh properties, mechanical properties, and durability of cement composites. Additionally, the mechanisms of carbon sequestration in BCC are analysed. Both physical and chemical methods can significantly modify the microstructure of BC, thereby enhancing its CO₂ adsorption capacity. With increasing CO₂ concentration, both the hydration and carbonation processes in cement composites are further enhanced. Finally, the carbon sequestration abilities and economic benefits of BCC are quantitatively summarised through related case studies. The effects of the physicochemical properties of BC on low-carbon cementitious composites are systematically analysed, demonstrating that BC with different properties exhibits significant variations in the carbon sequestration capacity of cementitious composites. Therefore, optimizing the physicochemical properties of BC represents an effective strategy for reducing the carbon emissions of cementitious composites.

生物炭（BC）可以增强胶凝复合材料的固碳能力，为减少碳排放提供了一种很有前景的策略。本研究从微观结构角度综述了生物炭-水泥复合材料（BCC）固碳能力的影响。首先，讨论了生物质类型、热解条件和活化方式对BC理化性质的影响。然后，通过微表征技术总结了不同类型BC对胶凝基质水化和碳化反应的影响。此外，BC显著影响水泥复合材料的新鲜性能、力学性能和耐久性。此外，还分析了BCC固碳的机理。物理和化学方法都能显著改变BC的微观结构，从而提高其CO2吸附能力。随着CO2浓度的增加，水泥复合材料的水化和碳化过程进一步增强。最后，通过相关案例，定量总结了BCC的固碳能力和经济效益。系统分析了BC的理化性质对低碳胶凝复合材料的影响，表明不同性质的BC对胶凝复合材料的固碳能力有显著差异。因此，优化BC的物理化学性质是减少胶凝复合材料碳排放的有效策略。

{"title":"Roles of biochar in improving carbon mineralisation and sequestration in sustainable cement–based materials","authors":"Zhaocheng Li , Zhiyu Luo , Wenkui Dong , Fulin Qu , Kejing Wang , Daniel C.W. Tsang , Wengui Li","doi":"10.1016/j.cemconcomp.2025.106403","DOIUrl":"10.1016/j.cemconcomp.2025.106403","url":null,"abstract":"<div><div>Biochar (BC) can enhance the carbon sequestration capacity of cementitious composites, offering a promising strategy for reducing carbon emissions. This study reviews the effects of BC on the carbon sequestration capacity of biochar–cement composites (BCC) from a microstructural perspective. Firstly, the effects of biomass type, pyrolysis conditions, and activation methods on the physicochemical properties of BC are discussed. Then, the effects of various types of BC on the hydration and carbonation reactions of cementitious matrices are summarised through micro-characterisation techniques. Moreover, BC significantly affects fresh properties, mechanical properties, and durability of cement composites. Additionally, the mechanisms of carbon sequestration in BCC are analysed. Both physical and chemical methods can significantly modify the microstructure of BC, thereby enhancing its CO<sub>2</sub> adsorption capacity. With increasing CO<sub>2</sub> concentration, both the hydration and carbonation processes in cement composites are further enhanced. Finally, the carbon sequestration abilities and economic benefits of BCC are quantitatively summarised through related case studies. The effects of the physicochemical properties of BC on low-carbon cementitious composites are systematically analysed, demonstrating that BC with different properties exhibits significant variations in the carbon sequestration capacity of cementitious composites. Therefore, optimizing the physicochemical properties of BC represents an effective strategy for reducing the carbon emissions of cementitious composites.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"166 ","pages":"Article 106403"},"PeriodicalIF":13.1,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145546299","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

Effect of modified biochar on the immobilization of Pb2+ and CrO42− in cement-based materials 改性生物炭对水泥基材料中Pb2+和CrO42−固定化的影响

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

Cement & concrete composites

Pub Date : 2025-11-13 DOI: 10.1016/j.cemconcomp.2025.106398

Binglin Guo , Di Lu , Ping Ye , Kaixuan Wang , Yuxing Gao , Huyong Qin , Yang Liu , Tongsheng Zhang , Lei Wang , Chuanzhen Wang , Binggen Zhan , Qijun Yu

Cement-based solidification/stabilization (S/S) is widely used for the treatment of hazardous waste because it is a low-cost and straightforward process. However, the immobilization efficiency of traditional cement systems for amphoteric and anionic heavy metals is insufficient. Therefore, improving the immobilization ability of cement-based materials for amphoteric and anionic heavy metal pollutants is the key focus of current research. Herein, we innovatively increased the adsorption capacity of anions using quaternary ammonium group-functionalized modified biochar and systematically investigated the adsorption mechanism of modified biochar for Pb²⁺ and CrO₄²⁻ under the alkaline conditions. Modified biochar was further incorporated into the cement matrix to evaluate its immobilization efficiency for Pb²⁺ and CrO₄²⁻ and its effect on the properties of cement-based materials. Results showed that the substitution of quaternized biochar reduced the leaching concentrations of Pb²⁺ and CrO₄²⁻ due to the positive charge of quaternized biochar under strong alkaline conditions, which reduced the electrostatic repulsion between anions and facilitated the adsorption of more heavy metal ions. Furthermore, due to the microfilling, internal curing, and hydration nucleation effects of biochar, biochar substitution improved the compressive strength of cement and the formation of hydration products. This study proposes a new strategy for preparing biochar–cement composite immobilization materials to address the bottleneck in cement-based S/S technology.

水泥基固化/稳定化（S/S）因其成本低、操作简单而被广泛用于危险废物的处理。然而，传统水泥体系对两性和阴离子型重金属的固定效率不足。因此，提高水泥基材料对两性和阴离子型重金属污染物的固定化能力是当前研究的重点。本研究创新性地利用季铵基功能化改性生物炭提高了阴离子的吸附能力，并系统地研究了改性生物炭在碱性条件下对Pb2+和CrO42−的吸附机理。进一步将改性生物炭掺入水泥基质中，评价其对Pb2+和CrO42−的固定化效率及其对水泥基材料性能的影响。结果表明：在强碱性条件下，生物炭季铵化后所带的正电荷降低了Pb2+和CrO42−的浸出浓度，降低了阴离子间的静电斥力，有利于吸附更多重金属离子。此外，由于生物炭的微填充、内部固化和水化成核效应，生物炭替代提高了水泥的抗压强度和水化产物的形成。本研究提出了一种制备生物炭-水泥复合固定材料的新策略，以解决水泥基S/S技术的瓶颈问题。

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引用次数: 0

Multiscale design and optimization of UHPC based on synergistic regulation of hydration activity, particle packing, and interfacial film 基于水化活性、颗粒堆积和界面膜协同调节的超高性能混凝土多尺度设计与优化

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

Cement & concrete composites

Pub Date : 2025-11-13 DOI: 10.1016/j.cemconcomp.2025.106393

Zhengxiang Mi , Yongjian Liu , Longbang Qing , Hongliang Zhang , Bo Zheng

This study proposes a multi-scale mechanism-driven mix design method for ultra-high-performance concrete (UHPC), using water/paste film thickness (t_WFT/t_PFT) as a cross-scale control parameter. The approach integrates hydration regulation, particle packing optimization, and film-thickness control to precisely coordinate supplementary cementitious material replacement ratio, multi-level particle gradation (including binders and aggregates), and fiber dosage, enabling holistic optimization of UHPC workability, strength, dimensional stability, and resource efficiency. Multi-scale experimental validation (at paste, concrete, and composite levels) demonstrated that the quaternary system PB41-20, with a 38.7 % cement replacement, achieved the highest packing density, optimal workability, and a 28-day compressive strength of 104.5 MPa (26.1 % higher than the reference) through co-optimization of gradation and t_WFT. The optimal t_WFT and t_PFT were identified as 0.02 μm and 50 μm, respectively. Aggregate gradation optimization reduced paste demand by 5.2 %, while improving compressive and flexural strengths by 8.3 % and 5.9 %. The incorporation of coarse aggregates further reduced paste content and autogenous shrinkage by 11.6 % and 33.5 %, respectively, while maintaining strength. At a fiber volume fraction of 1.5 %, UHPC and CA-UHPC exhibited optimal overall performance, with compressive strengths of 165.8 MPa and 163.7 MPa, along with tensile performance enhanced by up to 64.2 %. The synergy between coarse aggregates and fibers significantly suppressed autogenous shrinkage, resulting in a 44.1 % reduction at 14 days.

本研究提出了一种多尺度机制驱动的超高性能混凝土（UHPC）配合比设计方法，以水/膏膜厚度（tWFT/tPFT）作为跨尺度控制参数。该方法将水化调节、颗粒填充优化和膜厚控制集成在一起，精确协调补充胶凝材料替代比、多级颗粒级配（包括粘结剂和骨料）和纤维用量，实现UHPC可操作性、强度、尺寸稳定性和资源效率的整体优化。多尺度试验验证（膏体、混凝土和复合材料水平）表明，通过级配和tWFT的共同优化，水泥替代率为38.7%的PB41-20四元体系获得了最高的充填密度和最佳的和易性，28天抗压强度为104.5 MPa（比参考材料高26.1%）。结果表明，最优tWFT和tPFT分别为0.02 μm和50 μm。骨料级配优化后，膏体需求量降低了5.2%，抗压强度和抗折强度分别提高了8.3%和5.9%。粗集料的掺入进一步降低了膏体含量和自缩水率，分别降低了11.6%和33.5%，同时保持了强度。当纤维体积分数为1.5%时，UHPC和CA-UHPC的综合性能最佳，抗压强度分别为165.8 MPa和163.7 MPa，拉伸性能提高了64.2%。粗集料和纤维之间的协同作用显著抑制了自收缩，在第14天减少了44.1%。

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引用次数: 0

Carbonation resistance of low-carbon mortar blended with belitic calcium sulfoaluminate (BCSA) cement and its impact on initial corrosion of steel 低碳砂浆与贝氏体硫铝酸钙（BCSA）水泥的抗碳化性能及其对钢初腐蚀的影响

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

Cement & concrete composites

Pub Date : 2025-11-13 DOI: 10.1016/j.cemconcomp.2025.106399

Zhi Geng, Jinjie Shi

The blend of ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement has been well-established as a promising low-carbon binder in terms of matrix properties. However, the application in reinforced structures raises questions regarding its protective ability for the embedded steel, particularly concerning corrosion performance in carbonation environments. This study aims to evaluate the carbonation resistance of OPC-CSA blended mortar and investigate the related corrosion behavior of the embedded steel upon accelerated carbonation. The experimental findings indicate that, compared to OPC mortar, the reinforced blended mortar exhibited a deeper carbonation depth in the mortar matrix and a comparable corrosion rate of the embedded steel throughout the carbonation process. Although the OPC-CSA blended mortar showed higher overall porosity before and after carbonation compared to OPC mortar, the lower pore volume in the diameter range larger than tens of nanometers confirmed the finer pore size distribution of the blended mortar. Despite the negligible corrosion rates of the embedded steel, consistently below 0.1 μA cm⁻² for both mortars during the carbonation process, the characteristic of steel-mortar interface was found to influence the initial formation of corrosion stains.

普通硅酸盐水泥（OPC）与硫铝酸钙水泥（CSA）的共混物在基体性能方面是一种很有前途的低碳粘结剂。然而，在加固结构中的应用提出了关于其对预埋钢的保护能力的问题，特别是关于碳化环境中的腐蚀性能。本研究旨在评估OPC-CSA混合砂浆的抗碳化性能，并研究加速碳化作用下预埋钢的相关腐蚀行为。实验结果表明，与OPC砂浆相比，增强混合砂浆在砂浆基体中表现出更深的碳化深度，并且在整个碳化过程中，嵌入钢的腐蚀速度相当。虽然与OPC砂浆相比，OPC- csa砂浆碳化前后的整体孔隙率更高，但在直径大于几十纳米的范围内，其孔隙体积较低，证实了混合砂浆的孔径分布更细。尽管在碳化过程中，两种砂浆对预埋钢的腐蚀速率均小于0.1 μA⋅cm-2，可以忽略不计，但钢-砂浆界面的特性影响了腐蚀斑的初始形成。

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引用次数: 0

A novel framework for realistic modelling of 3D mesostructure and fracture behaviour of recycled aggregate concrete 再生骨料混凝土三维细观结构和断裂行为逼真建模的新框架

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

Cement & concrete composites

Pub Date : 2025-11-13 DOI: 10.1016/j.cemconcomp.2025.106396

Yi Ding , Sadjad Naderi , Gert van der Heijden , Mingzhong Zhang

Recycled aggregate concrete (RAC) offers a sustainable alternative to natural aggregate concrete, while its meso-scale modelling is often limited by overly simplified geometries. This study presents a novel 3D computational framework using Voronoi tessellation and hierarchical clustering to realistically generate 3D mesostructure of RAC. The model equips six distinct phases including old aggregate, old mortar, new mortar, two interfacial transition zones (ITZs) and voids, and employs splining and scaling techniques to control morphology. It produces irregular recycled aggregates with realistic size distribution, volume fraction, old mortar content, and shape descriptors in terms of sphericity, roundness and convexity. Validation indicates consistence with experimental findings in terms of geometry and composition. 3D meso-scale modelling of fracture processes in RAC under uniaxial compression can accurately capture the crack initiation at old ITZs and shear-dominated failure. The proposed modelling framework offers a robust tool for understanding the mesostructure-mechanical property relationships in RAC and optimising material design of RAC.

再生骨料混凝土（RAC）为天然骨料混凝土提供了一种可持续的替代方案，而其中尺度模型往往受到过于简化的几何形状的限制。本研究提出了一种新的三维计算框架，使用Voronoi镶嵌和分层聚类来真实地生成RAC的三维细观结构。该模型具有六个不同的阶段，包括旧骨料、旧砂浆、新砂浆、两个界面过渡区（ITZs）和空隙，并采用样条和结垢技术来控制形貌。它生产的不规则再生骨料具有真实的尺寸分布、体积分数、旧砂浆含量和球形、圆度和凹凸度方面的形状描述符。验证表明在几何和成分方面与实验结果一致。单轴压缩下RAC断裂过程的三维细观模型可以准确地捕捉到老断裂和剪切主导破坏的裂纹起裂过程。所提出的建模框架为理解RAC中的细观结构-力学性能关系和优化RAC的材料设计提供了一个强大的工具。

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引用次数: 0

Passivation and chloride-induced corrosion behavior of Zn-Al coated steel in belitic calcium sulfoaluminate cement system 锌铝包覆钢在贝氏体硫铝酸钙水泥体系中的钝化和氯化物腐蚀行为

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

Cement & concrete composites

Pub Date : 2025-11-12 DOI: 10.1016/j.cemconcomp.2025.106397

Jinjie Shi , Wenxuan Li , Xinhao Bi

As one of the low-carbon alternatives to ordinary Portland cement (OPC), belitic calcium sulfoaluminate (BCSA) cement has several benefits, such as rapid strength gain, low shrinkage and high durability. However, insufficient passivity was achieved for steel in BCSA cement due to its low alkalinity and high sulfates content. Despite the fact that these features are detrimental to the passivity of carbon steel, it should be underlined that the low-alkaline pore solutions of BCSA cement may prevent the dissolution of galvanized coating for galvanized steel, implying that galvanized steel may exhibit superior corrosion resistance when embedded in BCSA cement compared to OPC. To verify this hypothesis, the passivation behavior and chloride resistance were investigated for a Zn-Al coated steel in the OPC-BCSA blended system (abbreviated as PSA), including extract solutions and mortars, using electrochemical tests and microstructural characterization methods. The results indicate that the Zn-Al coated steel shows comparable passivation behavior in OPC and PSA systems, though it performs slightly differently in extract solutions and mortars. Nevertheless, compared to the OPC solution, improved chloride resistance is observed for the Zn-Al coated steel in the PSA solution, which is largely attributed to the presence of a stable retained Zn-Al coating. Furthermore, owing to the formation of a more compact steel-mortar interface, the enhanced corrosion resistance is more pronounced for the Zn-Al coated steel in the PSA mortar with the R_c + R_ct value of 351.0 kΩ cm², which is remarkably higher than that in the OPC mortar (9.2 kΩ cm²) after long-term chloride attack.

作为普通硅酸盐水泥（OPC）的低碳替代品之一，卑石质硫铝酸钙（BCSA）水泥具有强度增加快、收缩率低、耐久性高等优点。然而，由于BCSA水泥的低碱度和高硫酸盐含量，钢的钝化效果不足。尽管这些特性不利于碳钢的钝化，但需要强调的是，BCSA水泥的低碱性孔隙溶液可能会阻止镀锌钢的镀锌涂层的溶解，这意味着镀锌钢在BCSA水泥中嵌入时比OPC具有更好的耐腐蚀性。为了验证这一假设，采用电化学测试和微观结构表征方法，研究了锌铝涂层钢在OPC-BCSA混合体系（简称PSA）中的钝化行为和耐氯化物性，包括萃取液和砂浆。结果表明，锌铝涂层钢在OPC和PSA体系中表现出相当的钝化行为，尽管它在萃取液和砂浆中的表现略有不同。然而，与OPC溶液相比，在PSA溶液中观察到锌铝涂层钢的耐氯化物性能有所提高，这主要归功于锌铝涂层的稳定保留。此外，由于形成了更致密的钢-砂浆界面，锌铝涂层钢在PSA砂浆中的耐蚀性增强更为明显，Rc+Rct值为351.0 kΩ·cm2，显著高于长期氯离子侵蚀后在OPC砂浆中的抗蚀性（9.2 kΩ·cm2）。

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