Case Studies in Construction Materials最新文献_第7页

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

Pore characteristics and properties of calcium sulfoaluminate (CSA) foam concrete: Effects of foam content and water-to-binder ratio 硫铝酸钙（CSA）泡沫混凝土的孔隙特征和性能：泡沫含量和水胶比的影响

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

Case Studies in Construction Materials

Pub Date : 2025-12-16 DOI: 10.1016/j.cscm.2025.e05708

Yun-Lin Liu , Zi-Yao Tang , Xing-Yu Zhou , Dong Guo , Yan-Shuai Wang

Calcium sulfoaluminate (CSA) cement presents a promising alternative to Ordinary Portland Cement (OPC) in the production of ultra-lightweight foam concrete for marine applications, owing to its environmentally friendly characteristics and enhanced early strength development. This study investigates mixture optimization strategies to enhance the performance of ultra-lightweight CSA cement-based foam concrete. The macroscopic properties examined include flowability, density, compressive strength, and thermal conductivity. In addition, cross-sectional images of the specimens were analyzed to quantify key microscopic pore characteristics, such as porosity, pore size distribution, and pore roundness. These properties were systematically evaluated and compared to assess the effects of foam content (ranging from 59 % to 87 %) and water-to-binder ratio (ranging from 0.70 to 0.90). The results revealed that higher foam content and water-to-binder ratio significantly increased porosity and average pore diameter of the CSA foam concrete. Moreover, both compressive strength and thermal conductivity showed an inverse relationship with the porosity, while pore roundness further influenced these key properties.

硫铝酸钙（CSA）水泥由于其环保特性和增强的早期强度发展，在生产船舶应用的超轻量泡沫混凝土方面，它是普通波特兰水泥（OPC）的一个有希望的替代品。研究了提高CSA水泥基泡沫混凝土超轻量化性能的配合比优化策略。宏观性能包括流动性、密度、抗压强度和导热性。此外，还分析了样品的横截面图像，以量化孔隙率、孔径分布和孔隙圆度等关键微观孔隙特征。系统地评估和比较了这些性能，以评估泡沫含量（范围从59 %到87 %）和水胶比（范围从0.70到0.90）的影响。结果表明，较高的泡沫掺量和水胶比显著提高了CSA泡沫混凝土的孔隙率和平均孔径。此外，抗压强度和导热系数与孔隙率呈反比关系，而孔隙圆度进一步影响了这些关键性能。

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引用次数: 0

Sustainable microwave-hydrothermal synthesis for in-situ solidification of heavy-metal zinc in tobermorite 微波-水热合成法原位固化托贝莫里石中重金属锌

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

Case Studies in Construction Materials

Pub Date : 2025-12-16 DOI: 10.1016/j.cscm.2025.e05710

Shuqiong Luo , Shilei Gui , Lei Yang , Zhuangzhuang Jiang , Minghui Zhao , Guowen Sun , Zhenhe Tian , Jun Ren

Microwave hydrothermal synthesis can provide a sustainable way to prepare tobermorite, which can potentially efficiently solidify heavy metals by replacing calcium or silicon within its structure of tobermorite. In this paper, the feasibility of microwave hydrothermal process in solidifying heavy metal zinc (Zn) was investigated. The tobermorite was prepared from fumed silica and calcium hydroxide at Ca/Si of 0.83. The Zn-substituted tobermorite (Zn-tobermorite) was then prepared by adding Zinc chlorine under the Zn/Ca ratios of 0.05, 0.1, 0.15, 0.2, respectively. Additionally the characterisation of hydration product and the leaching behaviour of immobilised Zn was detected. Results indicated that the primary reaction products under both microwave and conventional hydrothermal conditions were Zn-tobermorite, tobermorite, gyrolite, hemimorphite, and reinhardbraunsite. During the synthesis of Zn-tobermorite, Zn²⁺ ions substituted for Ca²⁺ at an optimal Zn/Ca ratio of 0.15, achieving a Zn immobilization efficiency of 99.9 %. The microwave-assisted hydrothermal process reduced the synthesis time by approximately 85 % from 14 h to 2 h compared to conventional methods, while maintaining similar immobilization performance. This work offers a sustainable and time-efficient approach for heavy metal immobilization, showing significant potential for large-scale environmental remediation in industrial settings.

微波水热合成可以提供一种可持续的方法来制备托贝莫里石，它可以在托贝莫里石的结构中取代钙或硅，从而有效地固化重金属。研究了微波水热固化重金属锌的可行性。以气相二氧化硅和氢氧化钙为原料，在Ca/Si = 0.83的条件下制备了托伯莫里石。在锌钙比分别为0.05、0.1、0.15、0.2的条件下，通过添加氯锌制备了锌取代托伯莫里石（Zn-托伯莫里石）。此外，还检测了水化产物的表征和固定锌的浸出行为。结果表明，在微波和常规水热条件下，主要反应产物为锌-托伯莫来石、托伯莫来石、回转石、半铁锌矿和reinhardbraunsite。在制备Zn-托贝莫来石的过程中，Zn +取代Ca +的最佳Zn/Ca比为0.15，实现了99.9 %的Zn固定化效率。与传统方法相比，微波辅助水热工艺将合成时间从14 h减少到2 h，减少了约85 %，同时保持了相似的固定性能。这项工作为重金属固定提供了一种可持续和高效的方法，在工业环境中显示出大规模环境修复的巨大潜力。

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引用次数: 0

Durable phosphogypsum-based composite binders with ground-granulated blast furnace slag and carbide slag: Performance optimization and environmental assessment 含磨粒高炉渣和电石渣的耐用磷石膏基复合粘合剂：性能优化和环境评价

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

Case Studies in Construction Materials

Pub Date : 2025-12-16 DOI: 10.1016/j.cscm.2025.e05709

Xiaodong Wang , Guangcheng Long , Fan Wang , Junfeng Wen , Yuting Zhang , Changhe Huang , Ruxia Zhou

The global industrial challenges of massive phosphogypsum (PG) stockpiles, persistent underutilization, and inferior water resistance of conventional gypsum-based materials necessite innovative recycling strategies. Herein, we engineered a phosphogypsum-based composite binders (PBCB) by coupling ground-granulated blast furnace slag (GGBS) and carbide slag (CS) with anhydrous PG (APG) and β-hemihydrate PG (β-HPG). The compressive strength and water resistance of PBCB under air curing and water curing were investigated at 180d. Its phase composition, hydration process, pore structure, and microstructure were explored, followed by an evaluation of its environmental and economic benefits. Results showed that the combination of APG and β-HPG can significantly shortened the setting time of PBCB. Under the synergistic effect of hydration products, the mixture of 70 % APG/10 % β-HPG and 18 % GGBS/2 % CS shows the best performance. After 180d of air curing and water curing, the compressive strength and softening coefficient are 44.5 MPa, 0.83 and 41.9 MPa, 0.89, respectively. Notably, under water curing, the compressive strength decreases by only 4.17 %–10.32 %, while the softening coefficient increases by 6.74 %–12.64 %. In addition, the carbon emissions per unit strength and cost per unit strength are only 21.0 % and 35.7 % of those of ordinary Portland cement, respectively. This work establishes a viable technical pathway for transforming hazardous PG stockpiles (>80 million tons/year globally) into low-carbon sustainable binders.

大量磷石膏（PG）库存、持续利用不足和传统石膏基材料耐水性差的全球工业挑战需要创新的回收策略。本研究通过将磨粒高炉渣（GGBS）和电石渣（CS）与无水PG （APG）和β-半水PG （β-HPG）偶联，设计了磷石膏基复合粘合剂（PBCB）。研究了空气养护和水养护180d时PBCB的抗压强度和耐水性。探讨了其物相组成、水化过程、孔隙结构和微观结构，并对其环境效益和经济效益进行了评价。结果表明，APG与β-HPG联合使用可显著缩短PBCB凝固时间。在水化产物的协同作用下，70 % APG/10 % β-HPG和18 % GGBS/2 % CS的混合效果最佳。空气养护和水养护180d后，抗压强度和软化系数分别为44.5 MPa、0.83和41.9 MPa、0.89。值得注意的是，在水养护下，抗压强度仅降低4.17 % ~ 10.32 %，而软化系数增加6.74 % ~ 12.64 %。单位强度碳排放量和单位强度成本分别仅为普通硅酸盐水泥的21.0% %和35.7% %。本研究为危险PG库存（全球8000万吨/年）转化为低碳可持续粘合剂建立了可行的技术途径。

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引用次数: 0

Long-term performance and RSM-based optimization of fly-ash/bentonite synchronous grout for undersea shield tunnels 海底盾构隧道粉煤灰/膨润土同步灌浆长期性能及rsm优化

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

Case Studies in Construction Materials

Pub Date : 2025-12-16 DOI: 10.1016/j.cscm.2025.e05707

Mujeeb ur Rehman , Chao Liu , Hai Liu , Jie Cui , Pei Wang , Wei Chen

High-performance synchronous grouts are crucial for the watertightness and long-term serviceability of undersea shield-driven tunnels, and their mixing design remains largely empirical. This study combined an extensive laboratory campaign with response surface methodology (RSM) to develop a statistically optimized grout. Class F fly ash (0–25 wt%) and sodium bentonite (0–7.5 wt%) were used as additives to Portland cement. Initially, 30 mixes were assessed to determine the dosage of water and superplasticizer. Subsequently, 24 mixes were prepared with varying fly ash and bentonite ratios to assess the fresh properties (flow cone time, mini slump, table spread, and bleeding), compressive strength (28, 90, 180, and 360 days), scour resistance, and marine durability (water absorption, electrical resistivity, sorptivity, mass loss, and chloride penetration after immersion in synthetic seawater). Second-order RSM models (R² ≥ 0.97) accurately captured eight response variables and revealed strong fly ash–bentonite interactions: fly ash improved the long-term strength and chloride resistance, whereas bentonite suppressed bleeding but increased viscosity. Optimization identified 20 % fly ash and 4 % bentonite at a water-to-cement ratio (w/c) of 0.35 as the best compromise between workability and durability. The predicted mix achieved a 28-day strength of 75.95 MPa. The validation tests showed deviations of less than 5 % from the RSM predictions. Compared to the control group, mass loss and chloride ingress at 360 d were reduced by 81.4 % and 47.6 %, respectively. The resulting design charts and regression equations provide tunnel engineers with a data-driven tool for customizing synchronous grouts that meet stringent long-term performance requirements of tunnel boring machines.

高性能同步注浆对于海底盾构隧道的水密性和长期使用性至关重要，其配合比设计在很大程度上还停留在经验阶段。该研究结合了广泛的实验室活动和响应面法（RSM）来开发统计优化的灌浆。采用F级粉煤灰（0-25 wt%）和钠基膨润土（0-7.5 wt%）作为硅酸盐水泥的外加剂。最初，评估了30种混合物，以确定水和高效减水剂的剂量。随后，研究人员配制了24种不同粉煤灰和膨润土比例的混合料，以评估其新鲜性能（流锥时间、微坍落度、表展和放水）、抗压强度（28、90、180和360天）、耐冲刷性和海洋耐久性（吸水率、电阻率、吸附性、质量损失和浸泡在合成海水后的氯化物渗透）。二阶RSM模型（R²≥0.97）准确捕获了8个响应变量，并揭示了粉煤灰与膨润土之间的强相互作用：粉煤灰提高了长期强度和抗氯离子性，而膨润土抑制了出血，但增加了粘度。优化确定了20 %粉煤灰和4 %膨润土，水灰比（w/c）为0.35，是工作性和耐久性之间的最佳折衷。预测混合物的28天强度为75.95 MPa。验证测试显示与RSM预测的偏差小于5 %。与对照组相比，360 d的质量损失和氯化物摄入量分别减少了81.4 %和47.6 %。由此产生的设计图和回归方程为隧道工程师提供了一个数据驱动的工具，用于定制同步注浆，以满足隧道掘进机严格的长期性能要求。

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引用次数: 0

Nano-C-S-H seeds reinforced UHPC containing silica fume and metakaolin: Mechanism analysis and carbon footprint assessment 含硅灰和偏高岭土的纳米c - s - h种子增强UHPC：机理分析和碳足迹评价

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

Case Studies in Construction Materials

Pub Date : 2025-12-16 DOI: 10.1016/j.cscm.2025.e05698

Guanghong Lai , Zhenghe Sun , Siya Zhang , Feiyu Liao , Shiyu Li , Jinli Qian , Zhihong Lin

Decarbonization of ultra-high-performance concrete (UHPC) can be achieved by reducing cement consumption and optimizing the use of supplementary cementitious materials (SCMs). This study investigates the effects of nano-C-S-H seeds on the microstructural evolution mechanisms of ternary phase UHPC, which includes cement, silica fume (SF), and metakaolin (MK), while also quantifying the associated carbon footprint. The results indicate that nano-C-S-H seeds significantly enhance the pozzolanic reactions of SF and MK, reduce the induction period and acceleration period of cement hydration. This acceleration facilitates the formation of a more homogeneous and denser C-(A)-S-H micro-network structure, resulting in improved mechanical performance at 1 d, particularly in the blended SF-MK system. In addition, life cycle assessment results show that the combined effect of nano-C-S-H seeds and SCMs significantly lowers the carbon emissions associated with UHPC production. This study offers critical theoretical insights for developing UHPC with low carbon footprints and high early strength.

高性能混凝土（UHPC）的脱碳可以通过减少水泥消耗和优化补充胶凝材料（scm）的使用来实现。本研究探讨了纳米c - s - h种子对三元相UHPC（包括水泥、硅灰（SF）和偏高岭土（MK））微观结构演化机制的影响，同时量化了相关的碳足迹。结果表明，纳米c - s - h种子显著增强了SF和MK的火山灰反应，缩短了水泥水化的诱导期和加速期。这种加速有利于形成更均匀和更致密的C-(a)- s - h微网络结构，从而提高了1d时的机械性能，特别是在混合的SF-MK体系中。此外，生命周期评估结果表明，纳米c - s - h种子和SCMs的联合作用显著降低了与UHPC生产相关的碳排放。该研究为开发低碳足迹、高早期强度的UHPC提供了重要的理论见解。

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引用次数: 0

Laser-induced ice breaking and water penetration in extreme weather for precise rubber deposit removal on airport runways 在极端天气下，激光诱导破冰和水穿透，以精确清除机场跑道上的橡胶沉积物

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

Case Studies in Construction Materials

Pub Date : 2025-12-16 DOI: 10.1016/j.cscm.2025.e05704

Guodong Zhu , Donghe Zhang , Lei Zhang , Ke Li , Kaidi Liu , Bin Guo , Jie Xu

Airport runways are the lifeline of the aviation industry, and their maintenance plays a crucial role in ensuring flight safety. How to thoroughly remove the stubborn aircraft tire tread rubber layer under extreme working conditions (rainy/snow season) while ensuring the integrity of the cement or asphalt runway surface structure is an urgent technical challenge that needs to be overcome in the field of runway maintenance. This paper conducts laser rubber layer of different thicknesses removal tests on runways with different base structures (cement/asphalt) using nanosecond pulsed lasers under various laser conditions (power/spot overlap rate) and surface dry or wet states (sunny weather/rainy season/post-snow conditions). The laser rubber removal process database under different weather conditions was obtained using an optical microscope, high-speed camera, and pendulum friction coefficient tester, revealing the coupling mechanisms of laser ice breaking and water hazard penetration to remove rubber. The mapping relationship between the cleaning mechanism and laser conditions, rubber deposition thickness, and cleaning effect was established. There is a linear relationship between the laser ablation depth (Y) and the logarithm of laser energy (X): Y= 1.1X-0.31. The initial cleaning threshold for rubber deposition is 0.28 J/cm², and under sunny conditions, chemical combustion removal accounts for 2.24 % - 33.4 % of the entire removal mechanism, with optical thermal ablation mechanism dominating. Under the unit area (1 cm²), the laser energy consumed by 1 mm of ice layer is 1.8 J/cm². Under the action of the laser, the upper surface of the ice layer is melted, and the remaining laser passes through the ice layer and melts the bottom by heating the rubber deposit. Under the rainy season conditions, the plasma plume area decreases, the interaction between the pulsed laser and rubber deposition weakens, and the damage to the runway is reduced under the same laser flux, but it is not sufficient to completely avoid the excessive thermal effects. The research results can provide a solution to the safety dilemma of airport operations during rainy and winter seasons, and promote the construction of "safe, green, and smart" airports.

机场跑道是航空业的生命线，其维护对确保飞行安全起着至关重要的作用。如何在极端工况（雨雪季节）下彻底清除顽固的飞机轮胎胎面橡胶层，同时保证水泥或沥青跑道表面结构的完整性，是跑道维护领域急需克服的技术难题。本文利用纳秒级脉冲激光器，在不同激光条件（功率/光斑重叠率）和表面干湿状态（晴天/雨季/雨后）下，对不同基础结构（水泥/沥青）的跑道进行了不同厚度的激光橡胶层去除试验。利用光学显微镜、高速摄像机、摆锤摩擦系数测试仪等获得了不同天气条件下激光除胶过程数据库，揭示了激光破冰与水害穿透除胶的耦合机理。建立了清洗机理与激光条件、橡胶沉积厚度、清洗效果之间的映射关系。激光烧蚀深度(Y)与激光能量(X)的对数呈线性关系：Y= 1.1X-0.31。橡胶沉积的初始清洗阈值为0.28 J/cm2，在阳光条件下，化学燃烧去除占整个去除机制的2.24 % ~ 33.4 %，以光学热烧蚀机制为主。在单位面积（1 cm2）下，1 mm冰层所消耗的激光能量为1.8 J/cm2。在激光的作用下，将冰层的上表面熔化，剩余的激光通过加热橡胶沉积物，穿过冰层，将底部熔化。在雨季条件下，在相同的激光通量下，等离子体羽流面积减小，脉冲激光与橡胶沉积的相互作用减弱，对跑道的破坏减小，但不足以完全避免过度的热效应。研究成果可为解决雨季和冬季机场运行的安全困境提供解决方案，促进“安全、绿色、智慧”机场建设。

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引用次数: 0

Push-off tests and comparative evaluation of direct shear transfer behavior in normal, steel fiber-reinforced, and ultra-high-performance concrete 普通混凝土、钢纤维增强混凝土和超高性能混凝土的推离试验和直接剪切传递行为的比较评价

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

Case Studies in Construction Materials

Pub Date : 2025-12-15 DOI: 10.1016/j.cscm.2025.e05703

Qing Zhi , Guodong Zhang , Liqun Kang

This study investigates the direct shear behavior of normal concrete (NC), steel fiber–reinforced concrete (SFRC), and ultra–high–performance concrete (UHPC) through a systematic experimental program. Forty large–scale Z–shaped push–off specimens were tested under monotonic shear loading, with variations in fiber content, lateral confinement, reinforcement ratio, initial crack width, lap splice length, and reinforcement grade. Test results revealed that steel fibers significantly enhanced post–cracking resistance, residual strength, and energy dissipation, while lateral confinement and transverse reinforcement effectively limited slip and stabilized shear transfer. UHPC specimens exhibited superior shear capacity and stiffness, even with reduced lap splice lengths, establishing a clear performance hierarchy (UHPC > SFRC > NC) owing to their dense matrix and enhanced bond. Five performance indices—initial stiffness, peak shear strength, slip at peak, residual strength, and energy dissipation—were proposed for consistent evaluation, and regression–based sensitivity analysis highlighted the dominant roles of material type (especially UHPC), confinement, and reinforcement ratio. Furthermore, a unified regression–based shear strength expression was established, integrating cohesion, friction, reinforcement clamping, and fiber bridging, and achieved high predictive accuracy across all 40 specimens. Overall, the findings clarify the distinct contributions of NC, SFRC, and UHPC to shear transfer mechanisms and provide a unified expression and rational guidelines for the design of precast and composite joints in advanced concrete structures.

本研究通过系统的试验程序研究了普通混凝土（NC）、钢纤维增强混凝土（SFRC）和超高性能混凝土（UHPC）的直剪性能。在单调剪切荷载作用下，对40个大型z形推断试件进行了纤维含量、侧约束、配筋率、初始裂缝宽度、搭接长度和配筋等级的变化试验。试验结果表明，钢纤维显著提高了混凝土的抗裂后强度、残余强度和耗能能力，而横向约束和横向加固有效地限制了混凝土的滑移和稳定了剪切传递。UHPC试件表现出优异的抗剪能力和刚度，即使搭接长度减少，由于其致密的基体和增强的粘结，建立了明确的性能等级（UHPC > SFRC >； NC）。提出了五个性能指标——初始刚度、峰值抗剪强度、峰值滑移、残余强度和能量耗散——以进行一致性评估，基于回归的敏感性分析强调了材料类型（尤其是超高强度混凝土）、约束和配筋率的主导作用。此外，建立了一个统一的基于回归的抗剪强度表达式，整合了黏聚力、摩擦、钢筋夹紧和纤维桥接，并在所有40个试件中实现了较高的预测精度。总体而言，研究结果阐明了NC、SFRC和UHPC对剪切传递机制的不同贡献，并为高级混凝土结构中预制和组合节点的设计提供了统一的表达和合理的指导。

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引用次数: 0

Development and field based validation of a predictive model for concrete compressive strength using fresh state properties in a large scale construction project 大型建筑工程中基于新状态特性的混凝土抗压强度预测模型的开发与现场验证

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

Case Studies in Construction Materials

Pub Date : 2025-12-15 DOI: 10.1016/j.cscm.2025.e05705

Geovanny Solano-Vinueza , Jorge Albuja-Sánchez

Estimation of a compressive strength of concrete earlier than for a standard 28 day test remains a highly challenging issue in construction industry on a large scale, where the quality control is merged with efficient scheduling and sustainable construction. This work presents a predictive model validated under real field conditions, through the processing of data collected in 4872 concrete cylinders produced in an infrastructure work with a total cast volume of 25,000 m³. The models are based on fresh state parameters temperature, slump, air content, and density that are commonly tested in the field, and are used to predict 7 and 28 days compressive strength for 35 and 40 MPa designs. Selected were three statistical methods including multiple linear regression as the base method, principal component analysis for dimensionality reduction, and LASSO regularization with interaction terms. Cross validation results showed the robust performance and the adjusted R² value was as high as 0.71 and RMSE was less than 3.4 MPa. While LASSO tightened model parsimony and did not reduce prediction efficiency, PCA increased precision in the context of multicollinearity and only slightly at the cost of precision. A strong correlation between early and late strength (0.84 and 0.74 for 35 MPa and 40 MPa, respectively) supports the use of early age results as practical predictors. The compressive strength prediction module was validated with real project data, providing ±RMSE confidence bands for operational use. These findings demonstrate that statistical modeling can be integrated into quality control workflows, enabling data driven decisions in concrete production and placement.

在大规模的建筑行业中，比标准的28 天测试更早地估计混凝土的抗压强度仍然是一个极具挑战性的问题，在这个行业中，质量控制与有效的调度和可持续的施工相结合。通过处理总浇铸量为25,000 m³的基础设施工程中生产的4872个混凝土圆柱体收集的数据，本工作提出了一个在实际现场条件下验证的预测模型。该模型基于现场测试的新鲜状态参数温度、坍落度、空气含量和密度，并用于预测35和40 MPa设计的7天和28天抗压强度。选择了以多元线性回归为基础的统计方法、主成分降维分析方法和带交互项的LASSO正则化方法。交叉验证结果表明，该方法具有较好的鲁棒性，调整后的R²值高达0.71，RMSE小于3.4 MPa。LASSO收紧了模型的简约性，并没有降低预测效率，而PCA在多重共线性的情况下提高了精度，但仅以精度为代价。早期和晚期强度之间的强相关性（35 MPa和40 MPa分别为0.84和0.74）支持使用早期结果作为实际预测指标。用实际项目数据验证了抗压强度预测模块，为操作使用提供了±RMSE置信区间。这些发现表明，统计建模可以集成到质量控制工作流程中，从而在混凝土生产和放置过程中实现数据驱动决策。

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引用次数: 0

A developed SBS vitrimer for asphalt modification: Synergistic self-healing and aging resistance via dynamic covalent crosslinking 一种SBS沥青改性聚合物：通过动态共价交联实现协同自愈和耐老化

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

Case Studies in Construction Materials

Pub Date : 2025-12-15 DOI: 10.1016/j.cscm.2025.e05679

Guowei Hu , Ruiqi Chen , Zhifei Tan , Xueliang Jiang , Zhen Leng

This study develops a styrene-butadiene-styrene (SBS) vitrimer via disulfide bond-mediated dynamic covalent crosslinking to address the inherent aging susceptibility and non-healing properties of conventional SBS in asphalt modification. Epoxidized SBS (eSBS) was synthesized and crosslinked with 4,4′-dithiodibutyric acid (DTBA) to construct covalent adaptable networks. Fourier-transform infrared spectroscopy (FTIR) confirmed successful vitrimer formation through ester bond formation (1734 cm⁻¹ peak). Optical microscopy revealed rapid self-healing behavior in the optimized SBS vitrimer (SV3, 0.3 ‰ DTBA of the butadiene structural units in SBS), with surface notches fully closing within 50 min at 90 °C, whereas unmodified SBS exhibited no healing under identical conditions. Thermogravimetric analysis demonstrated comparable thermal stability between SV3 and pristine SBS, with maximum degradation temperatures (T_max) near 463 °C. Mechanically, SV3 achieved a 25 % increase in tensile strength while retaining 63 % elongation relative to SBS, along with 100 % creep recovery at 80–100 °C, contrasting with irreversible deformation in unmodified SBS. Aging resistance was evaluated via Rolling Thin Film Oven (RTFO) and Pressure Aging Vessel (PAV) tests. The SV3-modified binder (SV3mB) outperformed conventional SBS-modified binder (SBSmB), showing 54–58 % higher elastic recovery (R-value) and 19–20 % lower non-recoverable creep compliance (J_nr) post-RTFO aging. After PAV aging, SV3mB exhibited 46–105 % higher R-values and 62–70 % lower J_nr values. A healing index (H), derived from viscoelastic continuum damage (VECD) theory, quantified self-healing efficiency, revealing SV3mB’s superior damage mitigation under high strain (25 %–30 %) and extended fatigue life (N_f) due to dynamic bond exchange. These results demonstrate that SBS vitrimers enhance asphalt binder durability, aging resistance, and autonomous repair capabilities, offering transformative potential for pavement materials in extreme environmental conditions.

本研究通过二硫化物键介导的动态共价交联，开发了一种苯乙烯-丁二烯-苯乙烯（SBS）玻璃聚合物，以解决传统SBS在沥青改性中固有的老化敏感性和不愈合性。合成了环氧化SBS (eSBS)，并与4,4 ' -二硫代二丁酸（DTBA）交联构建共价自适应网络。傅里叶变换红外光谱（FTIR）证实，通过酯键形成成功形成了vitrimer（1734 cm−1峰）。光学显微镜显示，优化后的SBS vitrimer （SBS中丁二烯结构单元的SV3, 0.3 ‰DTBA）具有快速的自修复行为，在90°C下，表面缺口在50 min内完全关闭，而未修饰的SBS在相同条件下没有愈合。热重分析表明，SV3和原始SBS的热稳定性相当，最大降解温度（Tmax）接近463℃。机械上，与未改性SBS的不可逆变形相比，SV3的抗拉强度提高了25 %，同时相对于SBS保持了63 %的伸长率，在80-100°C时，与未改性SBS相比，SV3的蠕变恢复率为100 %。通过滚动薄膜烘箱（RTFO）和压力老化容器（PAV）试验对其抗老化性能进行了评价。sv3改性粘结剂（SV3mB）优于常规sbs改性粘结剂（SBSmB）， rtfo老化后弹性回复率（r值）提高54-58 %，不可恢复蠕变柔度（Jnr）降低19-20 %。经过PAV老化处理后，SV3mB的r值升高46-105 %，Jnr值降低62-70 %。从粘弹性连续损伤（VECD）理论得出的愈合指数(H)量化了自愈效率，揭示了SV3mB在高应变（25 % -30 %）下的优异损伤缓解效果，以及由于动态键交换而延长的疲劳寿命（Nf）。这些结果表明，SBS玻璃体增强了沥青粘合剂的耐久性、抗老化性和自主修复能力，为极端环境条件下的路面材料提供了变革潜力。

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引用次数: 0