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

Creep failure of alkali activated slag concrete in compression: Effect of loading age and stress level 碱渣混凝土受压蠕变破坏：加载龄期和应力水平的影响

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

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2025-12-30 DOI: 10.1016/j.cscm.2025.e05744

Ziyang Zhang , Xianggang Bian , Jianfei Kang , Tengfei Xu

With the rapid advancement of 3D printing, concrete is required to bear significant stress loads during its early-age period. The high stress creep failure behavior is directly associated with the structural stability and build ability requirements of 3D printed concrete elements during layer deposition. Nonlinear creep manifests in concrete subjected to high stresses. This process results in the accumulation of damage, which culminates in creep failure of concrete materials. However, limited information exists on this phenomenon in alkali-activated slag concrete. In this study, the creep failure of alkali-activated slag concrete under high uniaxial stress was investigated, and the creep failure characteristics of alkali-activated slag concrete were obtained. Additionally, the effects of loading age and stress ratio were investigated. The failure mechanism, creep coefficient, and nominal Poisson’s ratio of alkali-activated slag concrete specimens were investigated. Findings indicated that as age increases, the influence of loading age on the nonlinear creep of alkali-activated slag concrete progressively diminishes. Stress levels significantly affect the nonlinear creep of alkali-activated slag concrete. Specifically, when the stress level reached 0.95

f_{c}

, the alkali-activated slag concrete specimen failed after sustaining the load for a few seconds. During the creep phase, the circumferential creep coefficient and nominal Poisson’s ratio of the specimen exhibited a substantial increase, with the circumferential creep coefficient markedly exceeding the axial creep coefficient. Furthermore, the specimens exhibited significant lateral expansion upon destruction. Non-destructive and crack analyses were conducted to identify the creep-failure mechanism. The creep-failure study indicated that the propagation of microcracks inside the specimen influenced the nonlinear creep and creep-failure characteristics of alkali-activated slag concrete specimens subjected to high sustained compressive stress. The deterioration of the adhesive substance between particles progressively culminated in extensive fractures, which resulted in creep failure.

随着3D打印技术的快速发展，混凝土在早期阶段需要承受较大的应力载荷。高应力蠕变破坏行为直接关系到3D打印混凝土构件在层积过程中的结构稳定性和构建能力要求。混凝土在高应力作用下表现为非线性徐变。这一过程导致损伤的累积，最终导致混凝土材料的蠕变破坏。然而，关于碱活化矿渣混凝土中这种现象的研究资料有限。本研究对高单轴应力作用下碱活化渣混凝土的徐变破坏进行了研究，得出了碱活化渣混凝土的徐变破坏特征。此外，还研究了加载龄期和应力比的影响。对碱活化矿渣混凝土试件的破坏机理、蠕变系数和名义泊松比进行了研究。结果表明：随着龄期的增加，加载龄期对碱渣混凝土非线性徐变的影响逐渐减弱；应力水平对碱渣混凝土的非线性徐变有显著影响。其中，当应力水平达到0.95fc时，碱活化渣混凝土试件在承受荷载数秒后即失效。在蠕变阶段，试件的周向蠕变系数和名义泊松比均显著增大，且周向蠕变系数明显大于轴向蠕变系数。此外，试样在破坏后表现出明显的侧向膨胀。通过无损分析和裂纹分析来确定蠕变破坏机制。蠕变破坏研究表明，高持续压应力作用下碱活化渣混凝土试件内部微裂纹的扩展影响其非线性蠕变和蠕变破坏特性。颗粒间黏附物的劣化逐渐导致大面积断裂，从而导致蠕变破坏。

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引用次数: 0

Prediction of the hydration heat, temperature distribution and thermal stress of mass concrete 大体积混凝土水化热、温度分布及热应力预测

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

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2025-12-31 DOI: 10.1016/j.cscm.2025.e05748

Guowen Sun , Haorui Zheng , Liguo Wang , Liang Peng , Haitao Yang , Yifan Li

Thermal cracks induced by hydration heat are one of the primary factors affecting the durability of mass concrete structures. To accurately predict the early-age temperature rise and thermal stress of mass concrete, a hydration heat prediction model for Portland cement was established based on the Parrot-Killoh hydration kinetic model, considering the effects of water-cement ratio, cement fineness, relative humidity and temperature. Subsequently, taking the predicted hydration heat as the internal heat source, a finite element analysis model for the temperature and thermal stress fields of mass concrete was constructed. The influence laws of key parameters including water-cement ratio, cement fineness and curing temperature on the core temperature and thermal stress were systematically investigated. The results indicate that reducing the water-cement ratio or using finer cement significantly increases the peak core temperature and peak compressive stress of concrete; an increase in curing temperature accelerates the hydration reaction, raises the peak temperature and reduces the late-age tensile stress. Furthermore, a thermo-mechanical-damage coupled model based on the Mazars damage criterion was employed to simulate the early-age damage evolution process, revealing that damage tends to occur on the surface and edge regions within 24 h after casting. The multi-scale prediction method proposed in this study provides a reliable theoretical tool and engineering reference for temperature control and crack prevention design of mass concrete.

水化热引起的热裂缝是影响大体积混凝土结构耐久性的主要因素之一。为了准确预测大体积混凝土的早期温升和热应力，基于Parrot-Killoh水化动力学模型，考虑水灰比、水泥细度、相对湿度和温度的影响，建立了波特兰水泥水化热预测模型。随后，以预测的水化热为内热源，建立了大体积混凝土温度场和热应力场的有限元分析模型。系统研究了水灰比、水泥细度、养护温度等关键参数对岩心温度和热应力的影响规律。结果表明：降低水灰比或使用细水泥均显著提高混凝土的峰值芯温和峰值压应力；养护温度的升高加速了水化反应，提高了峰值温度，降低了后期拉伸应力。采用基于Mazars损伤准则的热-机-损伤耦合模型模拟了早期损伤演化过程，结果表明，在铸造后24 h内，损伤倾向于发生在表面和边缘区域。本研究提出的多尺度预测方法为大体积混凝土的温控防裂设计提供了可靠的理论工具和工程参考。

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引用次数: 0

Experimental investigation of HPMC inhibited crack sensitive of coral mud under extreme environmental conditions HPMC在极端环境条件下抑制珊瑚泥裂纹敏感性的实验研究

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

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2026-01-08 DOI: 10.1016/j.cscm.2026.e05762

Hong Wang , Chunyan Wang , Jinqiao Zhao , Zhenhua Ren , Xuanming Ding

Coral mud, widely distributed in the South China Sea, is highly prone to cracking, posing challenges for engineering applications. Hydroxypropyl methyl cellulose (HPMC), with superior water retention and crack inhibition capacity under hot and humid conditions, was introduced to improve the crack resistance of coral mud. This study conducted cracking and tensile tests to evaluate the effects of HPMC dosage (four levels) and environmental conditions on the cracking behavior and mechanical properties of coral mud. Results show that temperature and humidity markedly regulate water evaporation, with high temperature significantly accelerating moisture loss. HPMC effectively enhanced water retention and delayed cracking, with a 0.25 % dosage providing the optimal performance. It restricted crack length and refined crack width distribution while having little influence on crack orientation. The modification efficacy was strongly dependent on environmental conditions, showing the most significant improvement under high temperature and high humidity, where a 0.25 % dosage markedly enhanced crack resistance. Tensile tests confirmed that HPMC enhanced interparticle bonding and force transfer, particularly under high water content, whereas the effect was limited under low water content. This paper discussed the dual mechanism of HPMC to suppress cracking in coral mud by regulating evaporation and enhancing cohesion based on experimental results. Its findings provide practical guidelines for dosage and condition-specific application, supporting sustainable infrastructure development in the South China Sea.

南海广泛分布的珊瑚泥极易开裂，给工程应用带来了挑战。采用羟丙基甲基纤维素（HPMC）提高珊瑚泥的抗裂性能，使其在湿热条件下具有良好的保水性和抗裂能力。本研究通过开裂和拉伸试验，评价HPMC掺量（4级）和环境条件对珊瑚泥开裂行为和力学性能的影响。结果表明，温度和湿度对水分蒸发有显著调节作用，高温显著加速水分损失。HPMC有效地提高了保水性，延缓了开裂，0.25 %的投加量提供了最佳的性能。它限制了裂纹长度，细化了裂纹宽度分布，但对裂纹方向影响不大。改性效果与环境条件密切相关，在高温高湿条件下改性效果最为显著，0.25 %的掺量显著增强了材料的抗裂性。拉伸试验证实，HPMC增强了颗粒间的结合和力传递，特别是在高含水量下，而在低含水量下效果有限。根据实验结果，探讨了HPMC通过调节蒸发和增强粘聚力抑制珊瑚泥开裂的双重机理。其研究结果为剂量和特定条件的应用提供了实用指南，支持南海基础设施的可持续发展。

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引用次数: 0

Experimental and theoretical investigation of fiber-reinforced geopolymer mortars: Mix design optimization and bond behavior with brick masonry 纤维增强地聚合物砂浆的试验与理论研究：配合比优化及与砖砌体的粘结性能

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

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2026-01-05 DOI: 10.1016/j.cscm.2026.e05767

Lihua Niu , Xueying Nie , Nan Li , Junfeng Guan , Lielie Li , Chaopeng Xie , Shaohua Gao

Despite being utilized for thousands of years, masonry structures still face significant challenges in enhancing their integrity and durability, making the preservation of architectural heritage and the development of innovative repair solutions critical. Geopolymer mortar (GM), an environmentally friendly alternative to traditional cement-based materials, shows considerable promise in both new construction and repair of masonry structures. This study systematically investigated the effects of water-binder ratio, binder-sand ratio, water-reducing agent content, and curing age on the setting time, fluidity, compressive strength, and flexural strength of GM. Additionally, the bond strength between GM with different mix ratios and brick masonry was thoroughly examined, along with the bonding performance of fiber-reinforced geopolymer mortar (FRGM) with brick masonry. The findings of this study demonstrated that the water-binder ratio was a crucial factor influencing the workability of GMs. An increase in this ratio significantly prolonged the setting time and improved flowability, while the binder-sand ratio played a secondary role in affecting workability. The mechanical strength of GMs significantly improved by reducing both the water-binder and binder-sand ratios, as well as with prolonged curing. The optimal dosage of a superplasticizer effectively enhanced mortar strength. In addition, the shear bond strength between GM and brick masonry progressively decreased with increasing water-binder and binder-sand ratios. A model for calculating bond strength was proposed, with theoretical values closely aligning with experimental results. The bond strength between FRGM and brick masonry significantly increased with extended bond length, though the rate of increase gradually declined. The bond strength between carbon fiber mesh-reinforced geopolymer mortar and brick masonry was the highest among the three types of fiber meshes. Basalt fiber mesh exhibited a comparable bond strength, and glass fiber mesh exhibited the lowest bond strength. This study provided important experimental and theoretical support for the design and optimization of high-performance GMs in engineering structure application.

尽管砖石结构已经使用了数千年，但在提高其完整性和耐久性方面仍然面临着重大挑战，这使得建筑遗产的保护和创新修复解决方案的发展至关重要。地聚合物砂浆（GM）是传统水泥基材料的环保替代品，在新建和修复砌体结构方面都显示出相当大的前景。本研究系统研究了水胶比、胶砂比、减水剂含量、养护龄期等因素对GM的凝结时间、流动性、抗压强度和抗折强度的影响，并对不同配比的GM与砖砌体的粘结强度以及纤维增强地聚合物砂浆（FRGM）与砖砌体的粘结性能进行了深入研究。研究结果表明，水胶比是影响改性高分子材料和易性的关键因素。该比例的增加显著延长了凝固时间，改善了流动性，而胶砂比对和易性的影响是次要的。通过降低水胶比和胶砂比以及延长养护时间，GMs的机械强度得到了显著提高。最佳掺量的高效减水剂可有效提高砂浆强度。随着水胶比和胶砂比的增大，GM与砖砌体的抗剪粘结强度逐渐降低。提出了一种计算黏结强度的模型，理论值与实验结果吻合较好。随着粘结长度的延长，FRGM与砖砌体的粘结强度显著增加，但增加幅度逐渐下降。碳纤维网增强地聚合物砂浆与砖砌体的粘结强度在三种纤维网中最高。玄武岩纤维网具有相当的粘结强度，玻璃纤维网粘结强度最低。该研究为工程结构应用中高性能gm的设计与优化提供了重要的实验和理论支持。

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引用次数: 0

Enhancing early strength of cement mortar using MSWI fly ash under accelerated carbonation curing MSWI粉煤灰在加速碳化养护条件下提高水泥砂浆的早期强度

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

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2026-01-07 DOI: 10.1016/j.cscm.2026.e05779

Minseok Nam , Yunsu Lee , Jeado Han , Dongkyu Lee , Sungwon Jung , Myung-Sun Baek , Dongcheon Park , Kwangwoo Wi

Metallic Al in municipal solid waste incineration fly ash (MSWIFA) generates hydrogen gas in cement mortars, creating internal pores that typically reduce mechanical strength and necessitate pretreatment before use. This study aims to utilize these gas-induced pores as diffusion pathways for CO₂ during carbonation curing to maximize its effectiveness in cement mortars. Cement paste and mortar specimens were prepared by replacing cement with 2.5, 5, and 10 wt% of untreated MSWIFA. Their physical and chemical properties were evaluated through flowability, calorimetry, compressive strength, porosity, water absorption, Fourier-transform infrared spectroscopy, thermogravimetric-differential thermal analysis, and inductively coupled plasma tests. The chlorides in MSWIFA accelerated cement hydration but reduced flowability owing to increased viscosity. Although gas-induced pores reduced strength, they facilitated CO₂ penetration, which contributed to strength improvement through densification. Notably, the sample with 5 % MSWIFA (AFA5) showed the highest compressive strength after carbonation. In all specimens, Ca(OH)₂ and C-S-H transformed into CaCO₃, with AFA5 forming more metastable CaCO₃. Heavy metals such as Cu, Zn, and Pb were effectively immobilized by hydration products, while Cr leaching slightly increased owing to electrostatic repulsion. Carbonation resulted in a slight increase in heavy metal leaching; however, all values remained below the regulatory limits established by the United States Environmental Protection Agency, confirming the environmental safety.

城市固体垃圾焚烧飞灰（MSWIFA）中的金属铝在水泥砂浆中产生氢气，形成内部孔隙，通常会降低机械强度，需要在使用前进行预处理。本研究旨在利用这些气致孔隙作为CO₂在碳化养护过程中的扩散途径，使其在水泥砂浆中的效果最大化。用2.5、5和10 wt%未处理的MSWIFA代替水泥制备水泥浆和砂浆试件。通过流动性、量热法、抗压强度、孔隙率、吸水性、傅里叶变换红外光谱、热重-差热分析和电感耦合等离子体测试来评估它们的物理和化学性质。MSWIFA中的氯化物加速了水泥的水化，但由于粘度增加而降低了流动性。虽然气致孔隙降低了强度，但它们促进了二氧化碳的渗透，从而通过致密化提高了强度。值得注意的是，含5 % MSWIFA （AFA5）的样品碳化后抗压强度最高。在所有标本中，Ca(OH)2和C-S-H转化为CaCO3， AFA5形成更亚稳的CaCO3。水化产物对Cu、Zn、Pb等重金属具有有效的固定化作用，而Cr的浸出则因静电排斥作用而略有增加。碳化导致重金属浸出量略有增加；然而，所有数值均低于美国环境保护署规定的管制限值，证实了环境安全。

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引用次数: 0

A deep learning framework for microstructural analysis of nano-modified cementitious composites using metal intrusion and BSE imaging 基于金属侵入和BSE成像的纳米改性胶凝复合材料微观结构分析的深度学习框架

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

Case Studies in Construction Materials

Pub Date : 2026-07-01 Epub Date: 2025-12-11 DOI: 10.1016/j.cscm.2025.e05694

Zixuan Yu , Shuai Liang , Tong Liu , Yifei Ma , Yining Lin , Yuan Gao , Yanming Liu , Jinpeng Wang

Nanomodification is a promising technology for advancing construction materials toward multifunctionality, intelligence, and sustainability. However, current assessments of its effects on microstructure modification require improvements in objectivity, quantification, and pattern generalization. This study proposes a novel characterization-analysis framework, integrating metal intrusion technology with deep learning to enable expertise-independent extraction and evaluation of microstructure characteristics. Using image-based algorithms, the optimization of nanopore structure in cementitious waste rockfill material is first described. Based on a dataset comprising over 4000 microscopic images, the proposed deep learning model achieved a maximum 82.0 % accuracy at a 39.7 μm × 39.7 μm observation scale in distinguishing microstructure images of samples with various water-cement ratios and graphene oxide (GO) reinforcement. Porosity and fractal dimension show weak correlation with classification accuracy, suggesting insufficient description of these parameters on microstructure characteristics. The class activation mapping algorithm further revealed that the model consistently prioritized pore structure identification. The deep Taylor decomposition (DTD) algorithm extracted microstructure features that concentrated on the pore distribution near hydration products, where the GO groups exhibited denser and less continuous pore structure. Finally, a coefficient of variation matrix was employed to fuse micropores image data with DTD features data to generate typical pore probability distribution maps. Nanomodified pore structures exhibit discretized spatial distributions and lower overall pore probabilities, especially at low water-cement ratios. The established framework paves the way for intelligent, automated analysis of nanomodified microstructure, offering significant potential for future construction engineering applications of nanomaterials and deep learning technologies.

纳米修饰是一种很有前途的技术，可以推动建筑材料朝着多功能、智能化和可持续性的方向发展。然而，目前对其微观结构变化影响的评估需要在客观性、量化和模式泛化方面进行改进。本研究提出了一种新的表征分析框架，将金属入侵技术与深度学习相结合，实现了与专业知识无关的微观结构特征提取和评估。采用基于图像的算法，对胶凝废石填料的纳米孔结构进行了优化研究。基于超过4000张微观图像的数据集，在39.7 μm × 39.7 μm的观察尺度上，所提出的深度学习模型在区分不同水灰比和氧化石墨烯（GO）增强的样品的微观图像方面达到了82.0 %的最高准确率。孔隙度和分形维数与分类精度相关性较弱，说明孔隙度和分形维数对微观结构特征的描述不够充分。类激活映射算法进一步表明，该模型始终优先考虑孔隙结构识别。深度泰勒分解（deep Taylor decomposition， DTD）算法提取的微观结构特征集中在水化产物附近的孔隙分布上，其中氧化石墨烯基团表现出更致密、更不连续的孔隙结构。最后，利用变异系数矩阵将微孔隙图像数据与DTD特征数据融合，生成典型孔隙概率分布图。纳米修饰的孔隙结构表现出离散的空间分布和较低的总体孔隙概率，特别是在低水灰比时。所建立的框架为纳米修饰微观结构的智能、自动化分析铺平了道路，为纳米材料和深度学习技术的未来建筑工程应用提供了巨大的潜力。

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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 : 2026-07-01 Epub 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

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 : 2026-07-01 Epub 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 : 2026-07-01 Epub 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

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 : 2026-07-01 Epub 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