Cement & concrete composites最新文献_第5页

Comparative effects of nano-SiO2 and C-S-H seeds on mechanical property, sustainability, hydration, and microstructure of one-part sodium carbonate-activated slag 纳米sio2与C-S-H种子对单组分碳酸钠活化渣力学性能、可持续性、水化及微观结构的影响

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

Cement & concrete composites

Pub Date : 2025-12-21 DOI: 10.1016/j.cemconcomp.2025.106456

Mingkang Gao , Zhongtao Luo , Xiaohai Liu , Lei Liu , Jiayuan Ye , Ran Hai , Maoliang Zhang

One-part sodium carbonate-activated slag (SCAS) is a low-carbon cementitious material, but the early strength development is slow. To overcome the drawback, this study investigated the influence of nano-SiO₂ (NS) and C-S-H seeds on the early-stage compressive strength of SCAS system. A multi-technique approach, comprising pH monitoring, isothermal calorimetry, Krstulovic-Dabic model, XRD, TGA, ²⁷Al NMR, ²⁹Si NMR, MIP, and fractal analysis was employed to characterize the effects of nanomaterials on the hydration process, phase assemblage and pore structure of SCAS system, thereby elucidating the mechanisms governing early-age hydration behavior. The results revealed that compared to the control, the 0.2 wt% NS and C-S-H seeds increased the 1-day compressive strength of SCAS by 4 % and 329 %, corresponding to 5.4 MPa and 22.3 MPa respectively, whereas the 28-day strength remained virtually unaffected. The remarkable advantage was also reflected in sustainability. The SCAS sample with 0.2 wt% C-S-H seeds achieved a unit-strength cost of 19.4 CNY∗t⁻¹∗MPa⁻¹ and a unit-strength carbon emission of only 2.2 kg CO₂-e∗t⁻¹∗MPa⁻¹, both significantly lower than those of ordinary Portland cement and other modified alkali-activated slag systems. The C-S-H seeds markedly accelerated the rise in pH and advanced the onset of acceleration period to 23.2 h, shifting the hydration kinetics directly from crystal nucleation and growth to diffusion. Phase assemblage and pore structure further demonstrated that the seeding effect of C-S-H seeds significantly promoted slag dissolution and facilitated the formation of C-A-S-H gel, refining the pore structure. In contrast, although the early strength was marginally enhanced by NS, the competitive dissolution between NS and slag led to partial suppression of slag hydration.

单份碳酸钠活化渣（SCAS）是一种低碳胶凝材料，但早期强度发展缓慢。为了克服这一缺陷，本研究考察了纳米sio2 （NS）和C-S-H种子对SCAS体系早期抗压强度的影响。采用pH监测、等温量热法、Krstulovic-Dabic模型、XRD、TGA、27Al NMR、29Si NMR、MIP和分形分析等多技术表征了纳米材料对SCAS体系水化过程、相组合和孔隙结构的影响，从而阐明了早期水化行为的控制机制。结果表明，与对照相比，0.2 wt%的NS和C-S-H种子使SCAS的1天抗压强度分别提高了4%和329%，分别达到5.4 MPa和22.3 MPa，而28天的抗压强度几乎没有影响。这种显著的优势也反映在可持续性上。含有0.2 wt% C-S-H种子的SCAS样品的单位强度成本为19.4 CNY∗t−1∗MPa−1，单位强度碳排放量仅为2.2 kg CO2-e∗t−1∗MPa−1，均显著低于普通硅酸盐水泥和其他改性碱活化渣体系。C-S-H种子显著加速了pH的上升，加速开始时间提前至23.2 h，使水化动力学直接从结晶成核和生长转向扩散。相组合和孔隙结构进一步表明，C-S-H种子的播种效应显著促进了渣的溶解，促进了C-A-S-H凝胶的形成，细化了孔隙结构。矿渣与矿渣的竞争溶解作用导致矿渣水化作用受到部分抑制，但矿渣的早期强度略有提高。

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引用次数: 0

Rheological control of cementitious composites incorporating ceramic wastes for 3D printing applications 3D打印应用中含陶瓷废料胶凝复合材料的流变控制

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

Cement & concrete composites

Pub Date : 2025-12-19 DOI: 10.1016/j.cemconcomp.2025.106452

Lucia Ferrari , Giacomo Rizzieri , Liberato Ferrara , Elisa Franzoni

In response to the environmental impact of cement production and industrial discarded materials, this study explores the valorisation of ceramic wastes as replacement of clinker in low-carbon cementitious composites for application in additive manufacturing. Ceramic wastes from different sources were used as substitute of calcined clay in limestone calcined clay cement (LC3) mortar. The embodied CO₂ reduction of these new binders exceeds 40 % compared to Portland Cement (PC), thus representing a notable advancement in low-emission cementitious composites. The influence of six ceramic wastes on the fresh state performance of mortar was assessed through flow table tests and rheological measurements. A ball measuring system was used to assess viscosity, static yield stress, and their early-age evolution, combining the high resolution of benchtop rheometers with the possibility of testing of 3D-printable mortars with aggregates up to 2 mm, featuring high yield stress values. Numerical simulations based on the Particle Finite Element Method were then used to evaluate the printability of developed mix designs, avoiding time consuming trial and error testing campaigns and paving the way for through printing trials on a selected set of waste materials.

Numerical simulations highlighted that, while all tested formulations showed good performance for small-scale 3D printing, careful material selection becomes crucial when targeting larger structures to ensure stability and minimize deformation. Additionally, the simulations allowed prediction of material behaviour, particularly valuable given the high variability of waste-based constituents, emphasizing the innovative combination of circular economy concepts with a unique approach to additive manufacturing supported by numerical simulations.

为了应对水泥生产和工业废弃材料对环境的影响，本研究探讨了陶瓷废料作为低碳水泥复合材料熟料的替代品，在增材制造中的应用。利用不同来源的陶瓷废料代替煅烧粘土制备石灰石煅烧粘土水泥（LC3）砂浆。与波特兰水泥（PC）相比，这些新型粘合剂的二氧化碳排放量减少了40%以上，因此代表了低排放胶凝复合材料的显着进步。通过流动台试验和流变学测试，研究了6种陶瓷废料对砂浆新鲜状态性能的影响。使用球测量系统来评估粘度，静态屈服应力及其早期演变，结合台式流变仪的高分辨率和3d打印砂浆测试的可能性，骨料高达2mm，具有高屈服应力值。然后使用基于粒子有限元法的数值模拟来评估开发的混合设计的可打印性，避免了耗时的试验和错误测试活动，并为在选定的一组废物上进行印刷试验铺平了道路。数值模拟强调，虽然所有测试的配方都显示出小规模3D打印的良好性能，但在针对大型结构时，谨慎的材料选择变得至关重要，以确保稳定性和最小化变形。此外，模拟允许预测材料行为，考虑到基于废物的成分的高度可变性，这一点特别有价值，强调了循环经济概念与数值模拟支持的独特增材制造方法的创新结合。

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引用次数: 0

Synergistic effect of multi-supplementary materials on rheology and ultra-early stage properties of 3D printable FA-GBFS geopolymer 多种补充材料对可3D打印FA-GBFS地聚合物流变学和超早期性能的协同效应

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

Cement & concrete composites

Pub Date : 2025-12-18 DOI: 10.1016/j.cemconcomp.2025.106449

Yufei Yan , Mo Zhang , Guowei Ma

The rheological performance plays an important role in tailoring 3D printability of geopolymer. However, since geopolymer commonly incorporates industrial solid wastes, how these materials jointly affect the ultra-early rheology remains unclear and limits further optimization. To better modify the ultra-early stage properties of geopolymer, the supplementary materials of steel slag (SS), silica fume (SF), and flue gas desulfurization gypsum (FGD) were incorporated in fly ash (FA)-ground granulated blast furnace slag (GBFS) based geopolymer individually or in combination at 0–50 % to investigate their effects on the rheological properties and the underlying mechanisms via rheology tests, mini-slump measurement and microstructure characterization with freeze-dried paste samples after 3 min of mixing. The results indicated that the combined incorporation of SF-SS and SS-FGD mix had more significant influence on the rheology and ultra-early stage properties of FA-GBFS geopolymer. Due to the increased absorption of SF on SS, the dissolution of SF was enhanced by the higher alkalinity from SS and the internal resistance between particles was raised by the coated SS. This synergistic effect facilitated the development of dense and cohesive C(N)-A-S-H and C-S-H gel networks and remarkably improved the internal structural integrity and thixotropic recovery of geopolymer.

地聚合物的流变性能对其3D打印性能起着至关重要的作用。然而，由于地聚合物通常含有工业固体废物，这些材料如何共同影响超早期流变性尚不清楚，并限制了进一步的优化。为了更好地改性地聚合物的超早期性能，将钢渣（SS）、硅灰（SF）和烟气脱硫石膏（FGD）作为补充材料，分别以0 - 50%的比例添加到粉煤灰(FA)-磨粒高炉渣（GBFS）基地聚合物中，通过流变学试验研究了它们对地聚合物流变性能的影响及其机理。混合3 min后冻干膏体样品的微坍落度测量及微观结构表征。结果表明，SF-SS和SS-FGD混合料的掺入对FA-GBFS地聚合物的流变性能和超早期性能的影响更为显著。由于SS对SF的吸收增加，SS的高碱度增强了SF的溶解，包覆的SS提高了颗粒间的内阻，这种协同作用促进了致密和内聚的C(N) a - s - h和C- s - h凝胶网络的发展，显著提高了地聚合物的内部结构完整性和触变回收率。

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引用次数: 0

Synergistic enhancement of mechanical and impermeability properties in self-healing concrete through PVA fiber reinforcement and MICP 聚乙烯醇纤维增强和MICP对自愈混凝土力学性能和抗渗性能的协同增强

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

Cement & concrete composites

Pub Date : 2025-12-16 DOI: 10.1016/j.cemconcomp.2025.106450

Lu Jiang , Hongrui Ma , Sisi Hu , Xiangbi Zhao , Wenjing Wang , Yu Zhang , Yuanzhen Liu

The mechanical strength and impermeability of concrete are critical to its structural reliability and long-term durability. However, conventional concrete lacks autonomous crack-healing capacity, which can lead to progressive degradation under sustained mechanical and environmental stresses. This study presents a novel self-healing concrete system incorporating polyvinyl alcohol (PVA) fibers and microbially induced calcium carbonate precipitation (MICP), designed to synergistically improve both material performance and crack-sealing efficiency. Experimental results indicate that the inclusion of PVA fibers significantly enhances mechanical and durability properties. Compared to plain concrete, the 28-day compressive and flexural strengths increased by 32.47 % and 22.54 %, respectively, while water penetration depth was reduced by 23.25 %. Moreover, the relative permeability coefficient and volume of harmful capillary pores decreased by 50.81 % and 19.27 %, respectively. After 28 days of autonomous healing, the specimens exhibited a compressive strength recovery rate of 66.59 % and an ultrasonic pulse velocity recovery of 58.82 %. Microstructural analysis confirmed the precipitation of dense calcite crystals within cracks, contributing to pore refinement and intrinsic property enhancement. This work not only advances the autonomous healing capability of concrete but also substantially improves its mechanical and impermeable performance, offering a promising strategy for developing highly durable construction materials.

混凝土的机械强度和抗渗性能对其结构可靠性和长期耐久性至关重要。然而，传统的混凝土缺乏自主的裂缝愈合能力，这可能导致持续的机械和环境应力下的逐步退化。本研究提出了一种新型自修复混凝土体系，该体系包含聚乙烯醇（PVA）纤维和微生物诱导碳酸钙沉淀（MICP），旨在协同提高材料性能和止裂效率。实验结果表明，PVA纤维的加入显著提高了材料的力学性能和耐久性能。与素混凝土相比，其28天抗压强度和抗弯强度分别提高了32.47%和22.54%，而水侵深度则降低了23.25%。有害毛细孔的相对渗透系数和体积分别减小了50.81%和19.27%。经过28天的自主愈合，试件的抗压强度恢复率为66.59%，超声脉冲速度恢复率为58.82%。显微组织分析证实裂纹内析出致密方解石晶体，有助于孔隙细化和本征性能增强。这项工作不仅提高了混凝土的自主愈合能力，而且大大提高了混凝土的机械和抗渗性能，为开发高耐用建筑材料提供了一个有前途的策略。

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引用次数: 0

Synergistic mechanisms of magnesium slag on the reaction behavior of alkali-activated blast furnace slag 镁渣对碱活化高炉渣反应行为的协同作用机理

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

Cement & concrete composites

Pub Date : 2025-12-15 DOI: 10.1016/j.cemconcomp.2025.106434

Shiyu Zhuang , MiaoMiao Zhu , Ruoxin Zhai , Mingming Zhu , Yutao Guo , Zihan Zhou , Jianwei Sun , Xi Jiang , Qiang Wang

This study elucidates the synergistic mechanisms between magnesium slag (MS) and blast furnace slag (GGBS) in alkali-activated systems. Through an integrated analysis of reaction kinetics, phase assemblage, microstructure evolution and gel physicochemical characteristics, this work establishes the governing mechanism-microstructure-performance relationships for the systems. Results show that the reaction is governed by a composition-dependent, dual-stage interplay of competitive and synergistic pathways. The role of MS transitions from an initial diluent, which retards and diminishes the main GGBS exothermic peak, to an active synergistic partner. In the subsequent synergistic stage, the initial GGBS reaction provides the ion conditions and nucleation sites that trigger the hydration of MS, generating products that in turn accelerate the ongoing GGBS reaction. The addition of MS induces an Al-deficient condition, and triggers a competition where available Al preferentially partitions into the C-N-A-S-H gel, thereby inhibiting LDH formation. This in turn diverts the abundant Mg towards forming Al-independent phases such as M-S-H, brucite and magnesite. At moderate MS levels, a synergistic interplay promotes the co-precipitation of multiple gel and crystalline products, yielding a densified composite matrix. Conversely, excess MS renders the system GGBS-limited, resulting in a weak and porous matrix. Furthermore, MS promotes a dimensionally stable microstructure by diluting the overall shrinkage potential of the binder system, providing an internal restraining skeleton, and offering partial chemical compensation through expansion. The 50 % MS content is identified as optimal because it achieves the lowest strength-normalized cost and carbon footprint without compromising the effective immobilization of heavy metals.

本研究阐明了碱活化体系中镁渣（MS）与高炉渣（GGBS）的协同作用机理。通过对反应动力学、相组合、微观结构演化和凝胶物理化学特征的综合分析，建立了体系的控制机制-微观结构-性能关系。结果表明，该反应是由成分依赖的，竞争和协同途径的双阶段相互作用控制的。MS的作用从最初的稀释剂转变为一个积极的协同伙伴，它延缓和减少了主要的GGBS放热峰。在随后的协同阶段，初始的GGBS反应提供了触发MS水化的离子条件和成核位点，生成的产物反过来又加速了正在进行的GGBS反应。MS的加入诱导了Al缺乏状态，并引发了竞争，其中可用的Al优先分配到C-N-A-S-H凝胶中，从而抑制了LDH的形成。这反过来又使丰富的Mg转向形成与al无关的相，如M-S-H、水镁石和菱镁矿。在中等质谱水平下，协同作用促进多种凝胶和结晶产物的共沉淀，产生致密的复合基质。相反，过量的MS会使体系的ggbs受到限制，导致基质脆弱且多孔。此外，MS通过稀释粘合剂体系的整体收缩潜力，提供内部约束骨架，并通过膨胀提供部分化学补偿，从而促进了尺寸稳定的微观结构。50%的MS含量被认为是最佳的，因为它在不影响重金属有效固定的情况下实现了最低的强度标准化成本和碳足迹。

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引用次数: 0

Influence of wet joints on the shrinkage effects in steel-UHPC composite bridge decks: Monitoring and parametric analysis 湿缝对钢- uhpc组合桥面收缩影响的监测与参数分析

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

Cement & concrete composites

Pub Date : 2025-12-15 DOI: 10.1016/j.cemconcomp.2025.106438

Han Xiao , Wei Wang , Chen Xu , Biao Ma , Zhiping Yu , Huidan Xu

Ultra-high-performance concrete (UHPC) with a superior tensile mechanical property and durability is good for composite bridge deck overlays. However, its shrinkage effect may result in higher secondary stresses by the steel-UHPC interlayer interaction. Wet joints between UHPC segments, essential for construction, may make the secondary stresses more complicated to evaluate and address. So far, research regarding shrinkage-induced stress for joints in a composite system is quite limited and thus the mechanical mechanism has been rarely understood. To this end, 4 segmental composite girder specimens were manufactured for conducting static standing shrinkage effect monitoring. Numerical simulations were also executed concerning the effects of age differences, joint shapes, and reinforcement ratios. The monitoring results indicated that the UHPC shrinkage-induced strain distribution pattern as well as the level in the composite systems respectively with and without joints differs from each other. The simulation and parametrical analysis results indicated that rectangular and dovetailed joints exhibit lower interfacial tensile stresses due to enhanced contact area and shear resistance, while a critical 2-day casting time limit is identified to prevent joint tensile failure. Additionally, a higher reinforcement ratio could induce an increase in the shrinkage induced secondary stresses., while it will reduce the contribution of the steel plates and welded studs. The research results provide fundamental knowledge for the shrinkage mechanism understanding of wet joints in such UHPC composite systems. This is important for optimizing joint design and construction practices.

超高性能混凝土（UHPC）具有优异的拉伸力学性能和耐久性，是复合桥面覆盖层的理想材料。但其收缩效应可能会导致钢- uhpc层间相互作用导致二次应力增大。UHPC段之间的湿接缝对施工至关重要，可能使次级应力的评估和处理变得更加复杂。到目前为止，关于复合材料系统中节理收缩应力的研究非常有限，因此对其力学机制知之甚少。为此，制作了4个节段组合梁试件，进行静立收缩效应监测。数值模拟还执行了有关年龄差异，接缝形状和配筋率的影响。监测结果表明，在有节理和无节理的复合材料体系中，UHPC收缩应变的分布模式和水平存在差异。仿真和参数分析结果表明，矩形和燕尾接头由于增加了接触面积和抗剪能力，具有较低的界面拉应力，同时确定了防止接头拉伸破坏的关键铸造时间限制为2天。此外，较高的配筋率会导致收缩次生应力的增加。，同时会减少钢板和焊接螺柱的贡献。研究结果为了解此类UHPC复合材料湿缝收缩机理提供了基础知识。这对于优化接缝设计和施工实践具有重要意义。

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引用次数: 0

Designing high early-strength one-part hybrid cement mortar via incorporating highly-reactive artificial slag and pre-treated gypsum 采用高活性人工矿渣和预处理石膏配制高早强单组分混合水泥砂浆

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

Cement & concrete composites

Pub Date : 2025-12-14 DOI: 10.1016/j.cemconcomp.2025.106451

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

The study focused on developing a high-early-strength hybrid cement mortar using a low binder content of only 10 vol% OPC, supplemented by artificial slag (AS) and finely ground limestone powder (LP). The key objective was achieved with incorporating sodium hydroxide-treated gypsum waste (GW), designated as DAN (dry activator, Na-based). The inclusion of DAN (at 2 wt% sodium oxide equivalent: Na₂Oeq) significantly accelerated early hydration of the hardened mortar, yielding a remarkable 1-day compressive strength of 31.9 ± 1.6 MPa, nearly double that of the control without an activator. However, it concurrently negatively impacted one-year compressive strength, which is linked to an increase in pore diameter and the predicted inhibition of straetlingite formation, as indicated by thermodynamic modeling. Micro-computed tomography (micro-CT) and three-dimensional (3D) visualization revealed that this reduction is associated with clusters of low-density hydration products that formed early on and remain in the microstructure at later ages. In contrast, incorporating untreated GyW resulted in a lower early hydration acceleration rate but significantly enhanced the one-year compressive strength to 67.5 ± 0.8 MPa, surpassing that of DAN-containing mixtures (56.6 ± 1.8 MPa). This investigation elucidates a critical performance dichotomy, whereby untreated GyW emerges as a viable material for achieving superior long-term strength, while the treated GyW is demonstrated to enhance 1-day mechanical performance.

该研究的重点是开发一种高早强混合水泥砂浆，使用低粘结剂含量仅为10 vol%的OPC，辅以人工矿渣（AS）和细磨石灰石粉（LP）。通过掺入氢氧化钠处理的石膏废料（GW），实现了关键目标，指定为DAN（干活化剂，na基）。丹的加入（氧化钠当量为2wt %: Na2Oeq）显著加速了硬化砂浆的早期水化，1天抗压强度达到31.9±1.6 MPa，几乎是未添加活化剂的对照的两倍。然而，正如热力学模型所示，它同时对一年的抗压强度产生负面影响，这与孔径的增加和对平方石形成的预测抑制有关。微计算机断层扫描（micro-CT）和三维可视化（3D）显示，这种减少与早期形成的低密度水化产物簇有关，并在后期保持在微观结构中。相比之下，掺入未经处理的GyW的早期水化加速率较低，但一年抗压强度显著提高，达到67.5±0.8 MPa，超过了含dan的混合物（56.6±1.8 MPa）。这项研究阐明了一个关键的性能二分法，即未经处理的GyW成为实现卓越长期强度的可行材料，而经过处理的GyW被证明可以提高1天的机械性能。

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引用次数: 0

Carbonation property analysis and carbonation process modeling of GGBFS-based foam alkali-activated binder 基于ggfs的泡沫碱活化粘结剂碳化性能分析及碳化过程建模

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

Cement & concrete composites

Pub Date : 2025-12-12 DOI: 10.1016/j.cemconcomp.2025.106446

Jialong Lin , Suxi Wang , Heyuan Yu , Shenhao Ye , Jiaxi Mao , Shikun Chen , Yi Liu , Dongming Yan

In this study, the carbonation behavior of ground granulated blast furnace slag (GGBFS)-based foam alkali-activated binder was investigated under varied CO₂ curing conditions. An innovative in-situ observation approach was employed to continuously monitor the carbonation process in real time, allowing the progression of the carbonation front and stage evolution to be identified. Based on the results of multi-scale integrated analyses, a coupled diffusion–reaction kinetics model was established to quantitatively describe the spatiotemporal evolution of CO₂ transport and carbonate formation. This study proposes, for the first time, a three-stage diffusion process and a two-stage carbonation reaction mechanism, providing new insights into the multi-stage nature of carbonation in GGBFS-based foam alkali-activated binder. These findings refine the theoretical understanding of carbonation mechanisms in porous alkali-activated materials by elucidating the distinct diffusion and reaction stages.

在不同的CO2固化条件下，研究了矿渣粉（GGBFS）基泡沫碱活化粘结剂的碳化行为。采用创新的原位观测方法，对碳酸化过程进行实时连续监测，识别碳酸化前沿的进展和阶段演化。基于多尺度综合分析结果，建立了扩散-反应耦合动力学模型，定量描述了CO2输运与碳酸盐形成的时空演化过程。本研究首次提出了三阶段的扩散过程和两阶段的碳化反应机理，为ggfs基泡沫碱活化粘结剂的多阶段碳化性质提供了新的认识。这些发现通过阐明不同的扩散和反应阶段，完善了对多孔碱活化材料碳化机理的理论认识。

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引用次数: 0

The impact of fly ash on self-healing of slag-based engineered geopolymer composites 粉煤灰对渣基工程地聚合物复合材料自愈的影响

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

Cement & concrete composites

Pub Date : 2025-12-12 DOI: 10.1016/j.cemconcomp.2025.106447

Yiming Zhou , Mohamed Elchalakani , Pouria Ayough , Ali Sadakkathulla

This study explores the influence of varying fly ash dosages on the self-healing behaviour of slag-based engineered geopolymer composites (EGCs). The findings reveal that altering the fly ash content significantly impacts the self-healing performance of EGCs. Under dry-wet cycle conditions, EGCs with lower fly ash dosages exhibit enhanced self-healing, while in a sustained 10 % NaCl solution environment, higher fly ash dosages result in superior self-healing. This divergence in performance is attributed to the different healing products formed in each environment. Specifically, a mix design (Mix4 in this research) showed apparent 150 % recovery without completely visible crack healing, which is considered as extended strain capacity rather than healing of properties at the same strain range. This phenomenon is explained by the different mechanisms governing mechanical property recovery and crack healing. Mechanical recovery is primarily driven by the formation of healing products in the interface between the fibre and matrix, whereas crack healing relies on the extensive generation and accumulation of products within the cracks. These two mechanisms have varying demands for the quantity of healing products, with mechanical property recovery requiring significantly less than crack healing.

本研究探讨了不同粉煤灰用量对渣基工程地聚合物复合材料（EGCs）自愈行为的影响。研究结果表明，改变粉煤灰掺量会显著影响EGCs的自愈性能。在干湿循环条件下，低粉煤灰掺量的EGCs表现出较强的自愈能力，而在持续10% NaCl溶液环境下，高粉煤灰掺量的EGCs表现出较强的自愈能力。这种性能的差异归因于在每种环境中形成的不同愈合产品。具体来说，混合设计（本研究中的Mix4）在没有完全可见裂纹愈合的情况下显示出150%的明显恢复，这被认为是扩展应变能力，而不是在相同应变范围内的性能愈合。这种现象可以用控制力学性能恢复和裂纹愈合的不同机制来解释。机械恢复主要是由纤维和基体之间界面上愈合产物的形成驱动的，而裂纹愈合依赖于裂缝内产物的广泛产生和积累。这两种机制对修复产物的数量有不同的要求，力学性能的恢复需要明显少于裂纹愈合。

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引用次数: 0

Coupling moisture transport and modified equivalent age for enhanced prediction of compressive strength in mortar 耦合水分输运和修正等效龄期增强砂浆抗压强度预测

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

Cement & concrete composites

Pub Date : 2025-12-11 DOI: 10.1016/j.cemconcomp.2025.106448

Bochao Sun , Kechang Wu , Qiliang Zhao , Wei Wang , Weijian Zhao , Takafumi Noguchi , Yihai Jia , Qingkai Chen

The strength prediction model based on traditional maturity models fails to accurately predict the compressive strength of cement mortar under unsaturated curing, for neglecting spatiotemporal variations in internal humidity. To address this limitation, this study combines the internal moisture field with a strength model based on a humidity-corrected equivalent age function, thereby precisely capturing strength evolution driven by moisture diffusion and self-desiccation. Firstly, the degree of cement hydration was quantified at multiple temperatures (10–40 °C) and relative humidities (23–100 % RH) through thermogravimetric analysis, thereby enabling humidity correction of the traditional equivalent age function. Secondly, a finite difference model simulated the spatiotemporal moisture distribution within cylindrical specimens under different environmental conditions (10–40 °C, 70–100 % RH). Lastly, the simulated moisture field was incorporated into the corrected strength model to predict the overall compressive strength. Experimental validations confirmed that the moisture diffusion model accurately captured internal moisture evolution, with correlation coefficients (R) between predicted and experimental values reaching 0.84 for 5 cm diameter (∅5 cm) specimens and 0.94 for ∅10 cm specimens. Furthermore, the predicted compressive strengths exhibited excellent agreement with the experimental values, showing improved accuracy compared to traditional models. For the ∅5 cm and ∅10 cm specimens, the coefficients of determination (R²) were 0.94 and 0.956, the Root Mean Square Error (RMSE) values were 2.493 MPa and 2.158 MPa, and the Mean Absolute Error (MAE) values were 2.069 MPa and 1.843 MPa, respectively. This modeling approach provides a reliable theoretical framework and practical tool for predicting the strength of cement mortar under unsaturated curing conditions.

基于传统成熟度模型的强度预测模型由于忽略了内部湿度的时空变化，无法准确预测非饱和养护条件下水泥砂浆的抗压强度。为了解决这一局限性，本研究将内部水分场与基于湿度校正等效年龄函数的强度模型相结合，从而精确捕捉由水分扩散和自干驱动的强度演变。首先，通过热重分析，量化水泥在多种温度（10-40℃）和相对湿度（23-100% RH）下的水化程度，从而实现传统等效年龄函数的湿度校正。其次，利用有限差分模型模拟了不同环境条件（10 ~ 40℃，70 ~ 100% RH）下圆柱形试样内水分的时空分布。最后，将模拟的水分场与修正后的强度模型相结合，预测整体抗压强度。实验验证证实，水分扩散模型准确地捕捉了内部水分演化，5 cm直径（∅5 cm）试件的预测值与实验值的相关系数R为0.84，∅10 cm试件的相关系数R为0.94。此外，与传统模型相比，预测的抗压强度与实验值表现出良好的一致性，显示出更高的精度。∅5 cm和∅10 cm样本，决定系数（R2）分别为0.94和0.956，均方根误差（RMSE）分别为2.493 MPa和2.158 MPa，平均绝对误差（MAE）分别为2.069 MPa和1.843 MPa。该建模方法为非饱和养护条件下水泥砂浆的强度预测提供了可靠的理论框架和实用工具。

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