Case Studies in Construction Materials最新文献_第6页

Enabling recycled coarse aggregates in ductile ECC: A synergistic enhancement of mechanical and sustainability properties 使再生粗骨料在延性ECC：机械和可持续性性能的协同增强

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2025-12-19 DOI: 10.1016/j.cscm.2025.e05719

Yichao Wang , Zeen Hu , Sisi Feng , Yayun Qin , Haitao Yang , Guowen Sun , Yao Zhang

To meet the micro-mechanical design guidelines for achieving strain hardening and steady-state cracking behavior, the coarse aggregates are conventionally excluded from engineered cementitious composite materials. The absence of coarse aggregates leads to challenges, including enormous carbon emissions, elevated drying shrinkage, and reduced compressive strength. To overcome these limitations, this study explored the development of a novel ultra-high ductile concrete (UHDC) incorporating coarse aggregates, with the particular focus on the recycled coarse aggregates. The effects of coarse aggregate content (16 %, 20 % and 24 %) on the workability, drying shrinkage, and basic mechanical properties of UHDC were systematically investigated through the physical and mechanical tests. The results demonstrated that all the UHDC mixtures, both with natural and recycled coarse aggregates, consistently exhibited strain-hardening behavior and multiple micro-cracking characteristics. All the mixtures achieved the average tensile strains exceeding 5 %, while maintaining crack width below 150 μm. As the coarse aggregate content increased, the workability, drying shrinkage, tensile strength, and tensile strain exhibited progressive reduction, whereas the compressive strength demonstrated significant enhancement. Notably, compared to the mixture without coarse aggregates, UHDC containing 24 % coarse aggregates markedly reduced the 28-day shrinkage strain by 65.83 % to 450.56 µε, while simultaneously enhancing the compressive strength by 28.4 %, reaching 38.9 MPa. Furthermore, scanning electron microscopy and X-ray computed tomography (CT) tests were conducted to analyze the micro-structural and pore structure characterization, respectively. In addition, the study demonstrated that compared to the mixture without coarse aggregates, UHDC containing 24 % recycled coarse aggregates significantly reduced the energy consumption and carbon emissions by 18.38 % and 25.25 %, respectively. It was preliminary verified that the incorporation of coarse aggregate effectively enhanced the mechanical performance and promoted sustainability through waste concrete utilization.

为了满足实现应变硬化和稳态开裂行为的微力学设计准则，粗集料通常被排除在工程胶凝复合材料之外。缺乏粗骨料会带来挑战，包括大量的碳排放，干燥收缩率升高，抗压强度降低。为了克服这些限制，本研究探索了一种新型超高延性混凝土（UHDC）的发展，其中包括粗骨料，特别关注再生粗骨料。通过物理力学试验，系统研究了粗集料掺量（16 %、20 %和24 %）对UHDC和易性、干燥收缩率和基本力学性能的影响。结果表明，所有UHDC混合料，无论是天然粗骨料还是再生粗骨料，都表现出一致的应变硬化行为和多重微裂特征。所有混合物的平均拉伸应变均超过5 %，而裂纹宽度均保持在150 μm以下。随着粗集料掺量的增加，其和易性、干收缩率、抗拉强度和拉伸应变均呈递减趋势，而抗压强度则有显著提高。值得注意的是，与不含粗集料的混合料相比，含24 %粗集料的UHDC显著降低了28天收缩应变65.83 %至450.56µε，同时抗压强度提高28.4 %，达到38.9 MPa。通过扫描电子显微镜和x射线计算机断层扫描（CT）测试分别分析了微观结构和孔隙结构表征。此外，研究表明，与不含粗骨料的混合料相比，含有24% %再生粗骨料的UHDC可显著降低能耗和碳排放，分别降低18.38 %和25.25 %。初步验证了粗集料的掺入有效提高了废混凝土的力学性能，促进了废混凝土的可持续性。

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引用次数: 0

Valorization of municipal solid waste incineration bottom ash in ecological cement mortar: Mechanical enhancement, effective immobilization of hazardous heavy metals, and life cycle environmental benefits 城市生活垃圾焚烧底灰在生态水泥砂浆中的增值：机械增强、有害重金属的有效固定化、全生命周期环境效益

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2025-12-19 DOI: 10.1016/j.cscm.2025.e05718

Jun Yan, Zhaoxi Li, Jun Wang

This study investigates the utilization of municipal solid waste incineration bottom ash (IBA), pretreated via simple co-grinding and sieving, in ecological cement mortar (ECM) designed with a modified Andreasen–Andersen particle-packing model and an ultra-low water-to-binder ratio (w/b = 0.16). Mortars with 0–15 % IBA by mass replacing natural river sand were evaluated for mechanical, microstructural, and environmental performance. Strength improved at 5–10 % IBA, with the 10 % mix reaching a 28-day compressive strength of 127.6 MPa. XRD/TGA confirmed pozzolanic reactivity, showing ∼42.9 % consumption of Portlandite (Ca(OH)₂) and additional C–A–S–H formation. SEM and MIP revealed a densified matrix and refined pore structure. Leaching concentrations of Cu, Zn, Pb, and Cr were below regulatory thresholds, and mixes with 5–10 % IBA exhibited lower values than the control. Life-cycle assessment indicated that 15 % IBA reduced global warming potential by ∼9.8 % and yielded net benefits in ecotoxicity and human-toxicity categories due to avoided-burden credits. Overall, 10 % IBA provided the best balance between mechanical performance and environmental safety, whereas 15 % maximized environmental benefits, supporting the large-scale, low-cost use of IBA in sustainable construction materials.

本研究以改良的Andreasen-Andersen颗粒填料模型和超低水胶比（w/b = 0.16）设计的生态水泥砂浆（ECM）为研究对象，研究了经简单共磨和筛分预处理的城市生活垃圾焚烧底灰（IBA）的利用。以0-15 % IBA质量代替天然河砂的砂浆进行力学、微观结构和环境性能评价。强度在5-10 % IBA时有所提高，10 %混合物的28天抗压强度达到127.6 MPa。XRD/TGA证实了火山灰的反应性，表明波特兰石（Ca(OH)2）消耗了~ 42.9 %，并形成了额外的C-A-S-H。SEM和MIP分析表明，该材料具有致密的基体和精细的孔隙结构。Cu、Zn、Pb和Cr的浸出浓度低于规定的阈值，5-10 % IBA的浸出浓度低于对照。生命周期评估表明，15 % IBA使全球变暖潜势降低了~ 9.8 %，并且由于避免了负担信用，在生态毒性和人类毒性类别中产生了净效益。总体而言，10 %的IBA在机械性能和环境安全之间提供了最佳平衡，而15 %的IBA最大限度地提高了环境效益，支持IBA在可持续建筑材料中的大规模、低成本使用。

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引用次数: 0

Interfacial weakening mechanism and energy evolution of filling-type large-size cement-stabilized macadam for reflection crack mitigation 充填型大粒径水泥稳定碎石抗反射裂缝界面弱化机理及能量演化

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2025-12-19 DOI: 10.1016/j.cscm.2025.e05717

Dong Tang , Hailin Wang , Naitian Zhang , Jin Ran , Yongli Zhao , Jing Li

Reflection cracking is a critical issue affecting the durability of semi-rigid base asphalt pavements, primarily caused by the high shrinkage and limited crack resistance of conventional cement-stabilized macadam (CSM). To address this, a filling-type large-size cement-stabilized macadam (F-LSBC) base was developed, yet its interfacial weakening mechanism and corresponding impact on energy evolution remain unclear. This study combines micro- and macro-scale investigations to elucidate the crack resistance mechanism of F-LSBC compared with CSM. Nanoindentation testing was employed to quantify the micromechanical properties of the interfacial transition zone (ITZ), while splitting load–unload tests were conducted to analyze the releasable elastic strain energy and surface-layer energy evolution of the two materials. Results show that the ITZ in F-LSBC exhibits significantly lower elastic modulus (60 %–75 %) and hardness (55 %) than in CSM, along with higher porosity and a 1.5-fold larger volume fraction, confirming a pronounced interfacial weakening structure. Correspondingly, the dissipated energy proportion in F-LSBC reaches about 75 %, notably higher than the 60 % observed in CSM, leading to a 50 % reduction in its energy storage limit and a surface-layer energy less than 40 % that of CSM. These findings indicate that the intentional interfacial weakening in F-LSBC effectively reduces the transmission of shrinkage strain energy to the surface layer, thereby suppressing the formation of reflection cracks. This study provides the first quantitative nanoindentation-based confirmation of ITZ weakening in F-LSBC and provides quantitative evidence supporting the linkage between ITZ weakening and the reduction of surface-layer energy peak, offering theoretical guidance for the design of anti-cracking semi-rigid base materials.

反射裂缝是影响半刚性基层沥青路面耐久性的关键问题，其主要原因是常规水泥稳定碎石体的高收缩率和有限的抗裂性。为解决这一问题，研制了充填型大粒径水泥稳定碎石（F-LSBC）基层，但其界面弱化机制及其对能量演化的影响尚不清楚。本研究结合微观和宏观尺度的研究，阐明了F-LSBC与CSM的抗裂机理。采用纳米压痕测试量化界面过渡区（ITZ）的微观力学性能，采用劈裂加载-卸载测试分析两种材料的可释放弹性应变能和表面层能量演变。结果表明，与CSM相比，F-LSBC中ITZ的弹性模量（60 % ~ 75 %）和硬度（55 %）明显降低，孔隙率更高，体积分数大1.5倍，界面弱化结构明显。相应的，F-LSBC的耗散能量比例达到约75 %，明显高于CSM的60 %，导致其储能极限降低50 %，表层能量低于CSM的40 %。这些结果表明，F-LSBC中有意的界面弱化有效地减少了收缩应变能向表层的传递，从而抑制了反射裂纹的形成。本研究首次基于纳米压痕定量证实了F-LSBC中ITZ减弱，为ITZ减弱与表面层能量峰值降低之间的联系提供了定量证据，为抗裂半刚性基材的设计提供了理论指导。

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引用次数: 0

Pore distributive heterogeneity of cementitious materials by poker vibration: Quantification and modification 用扑克振动研究胶凝材料孔隙分布非均质性：量化与修正

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2025-12-19 DOI: 10.1016/j.cscm.2025.e05720

Zhiming Yu, Yimiao Huang, Wei Dong, Xiaokuan Zhao, Fang Wang, Guowei Ma

Vibration is a critical procedure in the production of cementitious materials to reduce porosity and improve compaction. However, the vibration energy of poker (inserted-type) vibrators exhibits spatial attenuation, which leads to pore distributive heterogeneity and results in uneven mechanical behavior of the material. The current study experimentally investigates the heterogeneity issue and quantifies the relevant efficient compaction zone (ECZ) for a single poker vibrator. Experimental results demonstrate that energy transmission of poker vibration becomes stable at 20 s and forms the ECZ with only 53.9 % coverage. The study confirms that certain difference of insertion depths between two adjacent vibrators can effectively improve the ECZ coverage and solve the corresponding heterogeneity problem. Subsequently, it formulates equations to determine the optimal depth difference and to develop a modified vibration mode. Compared to the conventional operation modes, the presented mode reduces the vertical porosity deviation from 2.46 % to 0.90 % and decreases the overall specimen porosity from 4.27 % to 2.47 %. And it achieves over 95 % ECZ coverage. The findings and the proposed method have applications in promoting the precise vibration control for the on-site cementitious material production.

振动是胶凝材料生产中降低孔隙率和提高压实度的关键工序。而插拔式振动器的振动能量表现为空间衰减，导致孔隙分布不均，导致材料力学行为不均匀。本研究通过实验研究了单个扑克牌振动器的非均质性问题，并量化了相关的有效压实区（ECZ）。实验结果表明，扑克振动的能量传输在20 s时变得稳定，形成的ECZ覆盖率仅为53.9% %。研究证实，相邻两振子插入深度的一定差异可以有效提高ECZ覆盖范围，解决相应的非均质性问题。在此基础上，建立了确定最优深度差的方程，并建立了改进的振动模式。与常规操作模式相比，该模式将垂直孔隙度偏差从2.46 %降低到0.90 %，将整体孔隙度从4.27 %降低到2.47 %。达到了95% %的ECZ覆盖率。研究结果和提出的方法对促进现场胶凝材料生产的精确振动控制具有一定的应用价值。

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引用次数: 0

High-strength self-compacting concrete incorporating red mud: Development and comprehensive performance evaluation 赤泥高强自密实混凝土的研制及综合性能评价

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2025-12-18 DOI: 10.1016/j.cscm.2025.e05714

Mohamed Inayathulla , Shamsad Ahmad , Tuba Iqbal , Mohammed A. Al-Osta , Syed K. Najamuddin , Asad Hanif

In this paper, red mud (RM), a highly alkaline waste material from aluminum production rich in alumina, iron, and silica, is used as a supplementary cementing material in developing high-strength self-compacting concrete (HS-SCC). The resulting fresh and hardened-state properties were determined. RM was added to HS-SCC in varying amounts to replace the cement. The results indicate that replacing cement with RM enhances the cohesiveness and flowability of SCC with improved mechanical and durability properties, due to its finer gradation and pozzolanic activity. The in-depth microstructural analysis by SEM showed enhanced packing density, densified pore structure, and interfacial strengthening. The optimal dosage of RM was determined as 10 %, leading to the 28-day compressive strength of the developed SCC > 57 MPa. The RM replacement at 30 % also significantly improved resistance against acid attack and water penetration, while the corresponding drying shrinkage was lower with improved stress-strain behavior. The enhanced properties are primarily due to greater strength and elastic modulus. These findings highlight the use of RM as a viable, sustainable cement substitute that can help resource conservation and environmental remediation in producing high-strength, high-performance self-compacting concrete.

本文以含氧化铝、铁和二氧化硅的高碱性铝生产废料赤泥（RM）为辅助胶凝材料，研制高强度自密实混凝土（HS-SCC）。测定了其新鲜状态和硬化状态的性能。在HS-SCC中加入不同量的RM来替代水泥。结果表明，用RM替代水泥，由于其级配更细，火山灰活性更强，可提高SCC的粘结性和流动性，改善其力学性能和耐久性。SEM分析结果表明：填料密度增强，孔隙结构致密，界面强化。RM的最佳添加量为10 %，得到的SCC 28天抗压强度>； 57 MPa。30% %的RM替换也显著提高了抗酸侵蚀和水渗透的能力，同时相应的干燥收缩率降低，改善了应力-应变行为。增强的性能主要是由于更大的强度和弹性模量。这些发现强调了RM作为一种可行的、可持续的水泥替代品的使用，可以帮助资源节约和环境修复，以生产高强度、高性能的自密实混凝土。

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引用次数: 0

Coupled mechanical-microstructural damage behavior of phosphoric acid-modified MOC under dry-wet-freeze-thaw cycling 干湿-冻融循环下磷酸改性MOC的力学-微观结构耦合损伤行为

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2025-12-17 DOI: 10.1016/j.cscm.2025.e05693

Jian Gong , Jiaxuan Zhang , Shuren Wang , Aichi Ma , Zhenzhen An

To address the drawbacks of magnesium oxychloride cement (MOC), phosphoric acid was employed to modify MOC cement. MOC cement exhibits poor water resistance, and in cold regions, it is subjected to a complex, multi-stress environment that significantly exacerbates its poor water resistance. Modifying MOC cement can improve its water resistance and thereby enhance its stability in cold regions. This experiment adopted a multi-scale design to simulate temperature variations in cold regions and investigated the effects of dry-wet-freeze-thaw (DWFT) cycle coupling on MOC cement. Mechanical strength, mineral composition, microstructural changes, and pore distribution were analyzed through uniaxial compressive strength (UCS) testing, X-ray diffraction (XRD), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR). Damage analysis was conducted on the test specimens based on the test results. The findings revealed that the strength loss of unmodified MOC exceeded 50 % after 20 DWFT cycles, whereas the strength of modified MOC increased by approximately 40 %. The addition of phosphoric acid prevented the dissolution of phase 5 crystals in the MOC system, and the porosity of the modified MOC cement decreased by about 50 %. A damage equation for specimens under DWFT cycles was derived and validated, enabling quantitative analysis of the impact of modifiers on MOC cement performance. The research findings hold significant importance for studying the durability and modification of MOC cement.

针对氯氧镁水泥（MOC）存在的缺陷，采用磷酸对MOC水泥进行改性。MOC水泥的耐水性较差，在寒冷地区，其经受复杂的多应力环境，显著加剧了其耐水性差。改性MOC水泥可以提高其耐水性，从而增强其在寒冷地区的稳定性。本试验采用多尺度设计模拟寒冷地区温度变化，研究干湿冻融（DWFT）循环耦合对MOC水泥的影响。通过单轴抗压强度（UCS）测试、x射线衍射（XRD）、扫描电镜（SEM）和核磁共振（NMR）等手段分析了机械强度、矿物组成、微观结构变化和孔隙分布。根据试验结果对试件进行损伤分析。结果表明，经过20次DWFT循环后，未改性MOC的强度损失超过50% %，而改性MOC的强度增加了约40% %。磷酸的加入阻止了MOC体系中5相晶体的溶解，改性MOC水泥的孔隙率降低了约50% %。推导并验证了DWFT循环下试件的损伤方程，从而定量分析了改性剂对MOC水泥性能的影响。研究结果对MOC水泥的耐久性和改性研究具有重要意义。

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引用次数: 0

Investigation on the high-temperature rutting failure of asphalt pavement structures under the combined effect of measured temperature and applied load 实测温度与外加荷载共同作用下沥青路面结构高温车辙破坏研究

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2025-12-17 DOI: 10.1016/j.cscm.2025.e05711

Tengfei Nian , Baosen Wu , Jiaqi Song , Mingjuan Zhang

The semi-rigid base pavement in the Jiayuguan area experiences significant challenges, particularly rutting deformation resulting from the combined effects of high-temperature weather and vehicle loads. By collecting meteorological data from the Jiayuguan area and inputting 24-hour temperature and solar radiation values during summer high-temperature periods, a solid heat transfer physical field and a surface radiation physical field were established to analyze the temperature distribution within the pavement structure. Two typical pavement materials, AC-16 and SMA-16, were selected as asphalt surface materials, with numerical simulations performed using the finite element software COMSOL Multiphysics to study asphalt pavement under combined environmental and vehicle loading conditions. Considering the temperature-dependent properties of asphalt mixtures (e.g., elastic modulus, creep coefficient), solid mechanical physical fields and vehicle load models were developed to estimate the mechanical response and rutting deformation of asphalt pavement under continuous temperature and load coupling conditions. The results indicate that the daily road surface temperature variation reaches 33.89°C, significantly impacting the material properties of asphalt mixtures. Under the combined effects of temperature and load, the mechanical response trends for pavements with AC-16 and SMA-16 surface materials are similar. Maximum vertical deformation, shear creep, and compressive creep all occur within the top 0–4 cm pavement depth, alternating between positive and negative across the transverse direction of the pavement. Compared to AC-16, SMA-16 exhibits reductions of 63.4 %, 22.4 %, 42.89 %, 45.29 %, 46.85 % and 27.19 % in positive and negative vertical deformations, making SMA-16 more suitable for enhancing the rutting resistance of asphalt pavement.

嘉峪关地区的半刚性基层路面面临着严峻的挑战，尤其是高温天气和车辆荷载共同作用下的车辙变形。通过收集嘉峪关地区的气象资料，输入夏季高温时期24小时的温度和太阳辐射值，建立固体传热物理场和表面辐射物理场，分析路面结构内部温度分布。选取AC-16和SMA-16两种典型路面材料作为沥青路面材料，利用COMSOL Multiphysics有限元软件对环境和车辆荷载复合条件下的沥青路面进行数值模拟。考虑沥青混合料的温度相关特性（如弹性模量、蠕变系数），建立了实体力学物理场和车辆荷载模型，以估计沥青路面在连续温度-荷载耦合条件下的力学响应和车辙变形。结果表明：路面温度日变化达到33.89℃，显著影响沥青混合料的材料性能；在温度和荷载共同作用下，AC-16和SMA-16路面的力学响应趋势相似。竖向变形最大值、剪切蠕变最大值和压缩蠕变最大值均出现在0 ~ 4 cm路面深度顶部，在路面横向上呈正负交替变化。与AC-16相比，SMA-16的正、负竖向变形量分别降低了63.4 %、22.4 %、42.89 %、45.29 %、46.85 %和27.19 %，更适合用于提高沥青路面抗车辙性能。

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引用次数: 0

Valorization of agricultural and industrial wastes in geopolymer foam concrete, a ternary binder approach using corncob ash, red mud, and fly ash 用玉米芯灰、赤泥和粉煤灰作三元粘结剂，使农业和工业废料在地聚合物泡沫混凝土中增值

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2025-12-17 DOI: 10.1016/j.cscm.2025.e05716

Fatheali A. Shilar , Dhafer Ali Alqahtani , Mubarakali Shilar , T.M. Yunus Khan

This study examines the growing need for sustainable and thermally efficient lightweight concretes, specifically through the advancement of geopolymer foam concrete (GFC). This novel material integrates industrial red mud (RM) and agricultural corncob ash (CCA) as partial replacements in a fly ash–based binder. This study aims to investigate the issues associated with foam instability, increased water absorption, and reduced mechanical strength that are commonly observed in waste-derived GFC materials. Six mix formulations (GC1–GC6) were developed by adjusting the CCA content from 0 to 250 kg/m³, and their rheological, thermal, mechanical, electrical, and microstructural properties were assessed. The measurement of compressive strength was conducted at both 3 and 28 days, whereas all additional tests were executed on samples that had been cured for 28 days.The findings indicated that the incorporation of moderate amounts of CCA (100–150 kg/m³) led to improvements in foam stability, enhanced thermal insulation properties, and preserved sufficient structural integrity, with GC3 demonstrating the highest 28-day compressive strength of 2.86 MPa. Excessive CCA (GC6) resulted in unstable pore structures, diminished gel formation, increased water absorption (62.7 %), and the lowest strength recorded (1.45 MPa). The thermal conductivity exhibited a reduction from 0.91 to 0.52 W/m·K, while the electrical resistivity demonstrated an increase from 6.1 to 35.2 Ω·m across the various mixes, suggesting enhanced insulating characteristics as the content of CCA increased. SEM–EDS analysis validated the presence of well-structured geopolymer gels in low-to-moderate CCA mixtures, while revealing disrupted matrices at elevated CCA concentrations.The findings of the study indicate that optimized RM–CCA–FA ternary binders are capable of generating lightweight, low-carbon GFC that exhibits enhanced thermal and electrical properties, thereby supporting the development of sustainable construction materials in accordance with the Sustainable Development Goals 9, 11, 12, and 13.

本研究考察了对可持续和热效率轻质混凝土日益增长的需求，特别是通过地聚合物泡沫混凝土（GFC）的进步。这种新型材料将工业赤泥（RM）和农业玉米芯灰（CCA）作为粉煤灰基粘合剂的部分替代品。本研究旨在探讨与泡沫不稳定性、吸水率增加和机械强度降低相关的问题，这些问题在垃圾衍生的GFC材料中普遍存在。通过将CCA含量从0调整到250 kg/m³，开发了6种混合配方（GC1-GC6），并对其流变、热、机械、电学和微观结构性能进行了评估。抗压强度测量分别在第3天和第28天进行，而所有额外的测试都是在固化28天的样品上进行的。研究结果表明，加入适量的CCA（100-150 kg/m³）可以改善泡沫稳定性，增强隔热性能，并保持足够的结构完整性，其中GC3的28天抗压强度最高，为2.86 MPa。过量的CCA （GC6）导致孔隙结构不稳定，凝胶形成减少，吸水率增加（62.7 %），强度最低（1.45 MPa）。导热系数从0.91降低到0.52 W/m·K，而电阻率从6.1增加到35.2 Ω·m，表明随着CCA含量的增加，绝缘特性增强。SEM-EDS分析证实了低至中等CCA混合物中结构良好的地聚合物凝胶的存在，同时发现CCA浓度升高时基质被破坏。研究结果表明，优化后的RM-CCA-FA三元粘合剂能够产生轻质、低碳的GFC，具有增强的热学和电学性能，从而支持可持续建筑材料的发展，符合可持续发展目标9、11、12和13。

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引用次数: 0

Enhancing the sulfate resistance of modified fly ash-based cementitious materials in marine environments using a graphene oxide–silane emulsion 利用氧化石墨烯-硅烷乳液增强改性粉煤灰基胶凝材料在海洋环境中的抗硫酸盐性

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2025-12-17 DOI: 10.1016/j.cscm.2025.e05712

Ruiyan Yu , Jinming Jiang , Shaochun Li , Renyu Geng , Koji Takasu , Weijun Gao

Concrete structures in marine environments are highly vulnerable to sulfate attack, which leads to microstructural degradation and severe durability loss. Modified fly ash (MFA), obtained by flotation to reduce unburned carbon, has shown promise as a supplementary cementitious material due to its pozzolanic reactivity and ability to refine pore structures. However, its performance remains limited under aggressive sulfate exposure. To address this challenge, this study evaluates the combined use of MFA and a graphene oxide-isobutyltriethoxysilane (GO/IBTS) composite emulsion as an internal modifier for improving hydration behavior and long-term durability. Comprehensive experimental analyses, including calorimetry, compressive strength testing, thermogravimetric analysis (TG), X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM), were conducted to assess hydration kinetics, microstructural evolution, and resistance to sulfate attack. The results reveal that low dosages of GO/IBTS emulsion (≤ 2 %) promote secondary hydration of MFA and refine the pore network, thereby enhancing structural stability during prolonged erosion. In contrast, higher dosages (> 2 %) significantly suppress cement hydration, increase total porosity, and lead to marked strength loss. Under sulfate exposure, the incorporation of GO/IBTS reduces the formation of expansive phases such as gypsum and calcium aluminate hydrates, effectively limiting internal cracking and ensuring long-term stability. This study demonstrates a novel and reliable strategy for enhancing the durability of MFA-based cementitious systems in marine environments. The findings provide both theoretical insights and practical guidance for the design of eco-friendly, sulfate-resistant construction materials.

海洋环境中的混凝土结构极易受到硫酸盐的侵蚀，导致其微结构退化和严重的耐久性损失。改性粉煤灰（MFA）通过浮选获得，以减少未燃烧的碳，由于其火山灰反应性和细化孔隙结构的能力，作为一种补充胶凝材料具有很大的前景。然而，在硫酸盐侵蚀下，其性能仍然有限。为了解决这一挑战，本研究评估了MFA和氧化石墨烯-异丁基三乙氧基硅烷（GO/IBTS）复合乳液作为内部改性剂的联合使用，以改善水化行为和长期耐久性。综合实验分析，包括量热法、抗压强度测试、热重分析（TG）、x射线衍射（XRD）、压汞孔隙法（MIP）和扫描电镜（SEM），以评估水化动力学、微观结构演变和抗硫酸盐侵蚀性。结果表明，低剂量的GO/IBTS乳液（≤2 %）促进了MFA的二次水化，细化了孔隙网络，从而提高了MFA在长时间侵蚀过程中的结构稳定性。相比之下，较高的掺量（> 2 %）显著抑制水泥水化，增加总孔隙度，并导致明显的强度损失。在硫酸盐暴露下，氧化石墨烯/IBTS的掺入减少了石膏和铝酸钙水合物等膨胀相的形成，有效地限制了内部开裂，确保了长期稳定性。该研究展示了一种新的、可靠的策略来提高mfa基胶凝系统在海洋环境中的耐久性。研究结果为环保、耐硫酸盐建筑材料的设计提供了理论见解和实践指导。

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引用次数: 0

Attention-enhanced neural networks and ensemble learning for accurate prediction of concrete carbonation 用于混凝土碳化准确预测的注意力增强神经网络和集成学习

IF 6.6 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials

Pub Date : 2025-12-17 DOI: 10.1016/j.cscm.2025.e05697

Zhixin Liu , Xiaodong Yang , Yuting Yang , Jili Qu

Concrete carbonation is a major contributor to reinforcement corrosion and durability loss in reinforced concrete, threatening structural integrity over time. While substantial research has been conducted on predicting carbonation depth using machine learning and deep learning techniques, many existing studies are limited by small datasets (300–600 samples) and a narrow focus on fly ash concrete, which restricts the robustness and generalizability of the models. In contrast, this study presents a novel approach by integrating a comprehensive dataset of 2163 samples from both natural and accelerated carbonation experiments, which is not confined to fly ash concrete. Eight key input variables were selected, and the dataset was randomly divided into training (80 %) and testing (20 %) subsets. Five predictive models were evaluated: Random Forest (RF), two baseline deep learning models (ANN and CNN), and two enhanced models that incorporate feature interaction terms, carbonation-related equations, and attention mechanisms (ATT-ANN and ATT-CNN). The results show that the enhanced models significantly outperform the baseline approaches in both accuracy and generalization. Specifically, ATT-CNN achieved the highest performance, reducing MSE by 24.6 % and 11.4 % relative to RF and CNN, respectively, and improving R² to 0.9142. ATT-ANN also demonstrated notable improvement, achieving an R² of 0.9063. Additionally, the integration of SHAP, Partial Dependence Plots (PDP), and Individual Conditional Expectation (ICE) methods provided deep insights into the decision-making process of the best-performing models. The findings indicate that carbonation time, temperature and humidity interactions, and the interaction between water-binder ratio and CO₂ concentration are the most influential factors in carbonation prediction. This study offers a novel, interpretable framework that not only enhances predictive accuracy and robustness but also deepens understanding of carbonation mechanisms, contributing to more scientifically rigorous service life assessments of reinforced concrete structures.

混凝土碳化是钢筋腐蚀和耐久性损失的主要原因，随着时间的推移威胁着结构的完整性。虽然利用机器学习和深度学习技术对预测碳化深度进行了大量研究，但许多现有研究受到小数据集（300-600个样本）和对粉煤灰混凝土的狭隘关注的限制，这限制了模型的鲁棒性和泛化性。相比之下，本研究提出了一种新的方法，通过整合来自自然碳化和加速碳化实验的2163个样本的综合数据集，这并不局限于粉煤灰混凝土。选取8个关键输入变量，将数据集随机分为训练子集（80 %）和测试子集（20 %）。评估了五种预测模型：随机森林（RF），两个基线深度学习模型（ANN和CNN），以及两个包含特征交互项、碳相关方程和注意力机制的增强模型（ATT-ANN和ATT-CNN）。结果表明，增强模型在精度和泛化方面都明显优于基线方法。其中，at -CNN达到了最高的性能，相对于RF和CNN分别降低了24.6 %和11.4 %的MSE，并将R²提高到0.9142。at - ann也表现出显著的改善，R²为0.9063。此外，SHAP、部分依赖图（PDP）和个体条件期望（ICE）方法的整合为最佳模型的决策过程提供了深入的见解。结果表明，碳酸化时间、温湿度相互作用、水胶比与CO₂浓度的相互作用是影响碳酸化预测的主要因素。本研究提供了一个新颖的、可解释的框架，不仅提高了预测的准确性和稳健性，而且加深了对碳化机制的理解，有助于更科学、更严格地评估钢筋混凝土结构的使用寿命。

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引用次数: 0