Pub Date : 2025-12-15DOI: 10.1016/j.cscm.2025.e05706
Sheng Li , Shuo Liu , Weiwei Wu , Wenzhong Zheng , Yiwei Zhong , Weichen Tian
Introducing appropriate coarse aggregate (CA) into ultra-high performance concrete (UHPC) can reduce costs and mitigate early cracking risks, while maintaining mechanical and durability properties. Ultra-high performance concrete with coarse aggregate (UHPC-CA) can demonstrate significant potential for transforming the construction industry. To investigate the local compression behaviors and failure mechanism of UHPC-CA, 9 specimens confined with spirals and steel fibers were tested under local loading conditions. The study focused on load response, failure mechanisms, cracking characteristics, and the relationship between local load and spiral strain. The wedge cleaving theory governed the failure mechanism of UHPC-CA, conceptualized as an arch structure with multiple tie rods under spiral confinement. The study identified two primary failure modes: splitting tensile failure and wedge shear failure, influenced by the middle and top bursting forces. Additionally, the parameter analysis was conducted, leading to the development and verification of a bearing capacity calculation model applicable to UHPC-CA with spirals.
{"title":"Local bearing capacity of steel fiber and spirals reinforced UHPC-CA: Mechanism analysis and calculation method","authors":"Sheng Li , Shuo Liu , Weiwei Wu , Wenzhong Zheng , Yiwei Zhong , Weichen Tian","doi":"10.1016/j.cscm.2025.e05706","DOIUrl":"10.1016/j.cscm.2025.e05706","url":null,"abstract":"<div><div>Introducing appropriate coarse aggregate (CA) into ultra-high performance concrete (UHPC) can reduce costs and mitigate early cracking risks, while maintaining mechanical and durability properties. Ultra-high performance concrete with coarse aggregate (UHPC-CA) can demonstrate significant potential for transforming the construction industry. To investigate the local compression behaviors and failure mechanism of UHPC-CA, 9 specimens confined with spirals and steel fibers were tested under local loading conditions. The study focused on load response, failure mechanisms, cracking characteristics, and the relationship between local load and spiral strain. The wedge cleaving theory governed the failure mechanism of UHPC-CA, conceptualized as an arch structure with multiple tie rods under spiral confinement. The study identified two primary failure modes: splitting tensile failure and wedge shear failure, influenced by the middle and top bursting forces. Additionally, the parameter analysis was conducted, leading to the development and verification of a bearing capacity calculation model applicable to UHPC-CA with spirals.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05706"},"PeriodicalIF":6.6,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-15DOI: 10.1016/j.cscm.2025.e05701
Decai Wang , Xiyang Hou , Ziming Liu , Zongyuan Wu , Shi Dong , Dongfa Han
This study proposes a novel shear index-centered design framework for emulsified asphalt cold recycled mixtures (ECRM) to overcome the limitations of the Marshall design method. A comprehensive system was developed by integrating gyratory compaction, Lorentz function-based pore analysis, and Mohr-Coulomb theory, optimizing compaction parameters and mechanical performance. Experimental results indicate that 50 gyrations achieve optimal compaction, reducing emulsified asphalt content by 0.5 % and water demand by 0.6 % compared to the Marshall method, while increasing dry density to 2.116 g/cm³ . A critical innovation of this study lies in the novel, first-time integration of Lorentz-function-based pore analysis and Mohr–Coulomb shear theory for ECRM design. The Lorentz function not only quantifies the similarity of pore distribution between gyratory compaction specimens and field cores (peak void volume: 0.28 mm³ vs. 0.25 mm³, deviation 12 %) and also provides a micro-scale benchmark for shear-parameter optimization. Based on this benchmark, shear parameters (cohesion c and internal friction angle φ) are innovatively derived from indirect tensile strength (ITS) and unconfined compressive strength (UCS) via simplified Mohr-Coulomb-derived formulas, which avoids the tedious triaxial tests required by traditional methods. Laboratory validations confirm superior performance, including a dynamic stability of 4557 cycles/mm, a freeze-thaw split ratio of 77.6 %, and a low-temperature failure strain of 2160 . Field validations across four expressway projects (e.g., Beijing-Hong Kong-Macao) demonstrate early-stage structural performance and over 10 years of service without rutting or significant cracking. This integrated design system establishes a quantitative correlation between "microscopic pores and macroscopic shear performance", provides theoretical support for the design and construction of ECRM, and promotes the standardized application of cold recycling technology.
{"title":"Optimizing shear performance of emulsified asphalt cold recycled mixtures via gyratory compaction: Mechanisms, design, and field validation","authors":"Decai Wang , Xiyang Hou , Ziming Liu , Zongyuan Wu , Shi Dong , Dongfa Han","doi":"10.1016/j.cscm.2025.e05701","DOIUrl":"10.1016/j.cscm.2025.e05701","url":null,"abstract":"<div><div>This study proposes a novel shear index-centered design framework for emulsified asphalt cold recycled mixtures (ECRM) to overcome the limitations of the Marshall design method. A comprehensive system was developed by integrating gyratory compaction, Lorentz function-based pore analysis, and Mohr-Coulomb theory, optimizing compaction parameters and mechanical performance. Experimental results indicate that 50 gyrations achieve optimal compaction, reducing emulsified asphalt content by 0.5 % and water demand by 0.6 % compared to the Marshall method, while increasing dry density to 2.116 g/cm³ . A critical innovation of this study lies in the novel, first-time integration of Lorentz-function-based pore analysis and Mohr–Coulomb shear theory for ECRM design. The Lorentz function not only quantifies the similarity of pore distribution between gyratory compaction specimens and field cores (peak void volume: 0.28 mm³ vs. 0.25 mm³, deviation 12 %) and also provides a micro-scale benchmark for shear-parameter optimization. Based on this benchmark, shear parameters (cohesion c and internal friction angle φ) are innovatively derived from indirect tensile strength (ITS) and unconfined compressive strength (UCS) via simplified Mohr-Coulomb-derived formulas, which avoids the tedious triaxial tests required by traditional methods. Laboratory validations confirm superior performance, including a dynamic stability of 4557 cycles/mm, a freeze-thaw split ratio of 77.6 %, and a low-temperature failure strain of 2160 <span><math><mrow><mi>μ</mi><mi>ε</mi></mrow></math></span>. Field validations across four expressway projects (e.g., Beijing-Hong Kong-Macao) demonstrate early-stage structural performance and over 10 years of service without rutting or significant cracking. This integrated design system establishes a quantitative correlation between \"microscopic pores and macroscopic shear performance\", provides theoretical support for the design and construction of ECRM, and promotes the standardized application of cold recycling technology.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05701"},"PeriodicalIF":6.6,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reinforced concrete (RC) structures have become increasingly prevalent in infrastructure construction. Ensuring their safety and managing maintenance within limited budgets necessitates effective health monitoring techniques, with non-destructive testing (NDT) methods playing a critical role. Among these, acoustic wave sound emission diagnostics traditionally rely on specialized expertise and sophisticated. This reliance may introduce potential inaccuracies due to interpretive errors and the limited availability of experts. This study focuses on the development of an AI-driven evaluation method for tapping sound analysis using an unsupervised deep learning approach. A laboratory case study was conducted using five RC beams of 2 m length and 0.2 m square cross section, subjected to electrochemical acceleration to simulate random corrosion in steel reinforcements. A total of 6075 tapping sound samples were collected and analyzed using frequency-domain transformations and clustering algorithms. Results showed that the proposed method generated an anomaly index that correlated with both the mass loss of steel reinforcement and surface crack severity. This case study highlights the potential of combining acoustic-based NDT with AI-driven analysis to support early-stage damage detection and improve condition assessment of RC structures.
{"title":"Application of unsupervised AI-assisted acoustic wave sound analysis for non-destructive detection of steel corrosion induced deterioration","authors":"Nopphanan Phannakham , Katsufumi Hashimoto , Yasuhiko Sato , Naoshi Ueda","doi":"10.1016/j.cscm.2025.e05702","DOIUrl":"10.1016/j.cscm.2025.e05702","url":null,"abstract":"<div><div>Reinforced concrete (RC) structures have become increasingly prevalent in infrastructure construction. Ensuring their safety and managing maintenance within limited budgets necessitates effective health monitoring techniques, with non-destructive testing (NDT) methods playing a critical role. Among these, acoustic wave sound emission diagnostics traditionally rely on specialized expertise and sophisticated. This reliance may introduce potential inaccuracies due to interpretive errors and the limited availability of experts. This study focuses on the development of an AI-driven evaluation method for tapping sound analysis using an unsupervised deep learning approach. A laboratory case study was conducted using five RC beams of 2 m length and 0.2 m square cross section, subjected to electrochemical acceleration to simulate random corrosion in steel reinforcements. A total of 6075 tapping sound samples were collected and analyzed using frequency-domain transformations and clustering algorithms. Results showed that the proposed method generated an anomaly index that correlated with both the mass loss of steel reinforcement and surface crack severity. This case study highlights the potential of combining acoustic-based NDT with AI-driven analysis to support early-stage damage detection and improve condition assessment of RC structures.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05702"},"PeriodicalIF":6.6,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.cscm.2025.e05663
Farnaz Saadat, Mohammad Zia Alavi, Fateme Labbafi
This study presents a comparative life cycle assessment and lifecycle cost analysis of seven chip-seal preventive maintenance treatments (Single, Double, and Triple chip seals; Scrub seal; Cape seal; Fiber-modified chip seal; and Rubberized chip seal) using a cradle-to-construction system boundary. Environmental impacts were quantified with SimaPro v9 (Ecoinvent) using the ReCiPe 2016 Endpoint (H) method for a functional unit of 1 m² of treated pavement and for the economic analysis, documented U.S. project costs and the Iranian price list were used and annualized with a 10 % discount rate. Results indicate that, under a cradle-to-construction boundary, Single Chip Seal and Scrub Seal have the lowest total normalized costs (1.88 and 2.6 USD/), while Rubberized and Triple Chip Seals show the highest total costs (7.06 and 6.28 USD/). When costs are annualized by service life, Single chip seal and Scrub seal remain the least costly (0.5 and 0.69 USD/), whereas Fiber chip seal, Cape seal and Triple chip seal are the most expensive ones (1.03, 1.05, and 1.05, respectively). From an environmental standpoint, Scrub Seal has the lowest total GHG emissions (≈1545 g CO₂e) and the lowest weighted endpoint scores across Human Health, Ecosystems and Resources, whereas Cape Seal and Triple Chip Seal are the worst performers (Cape seal total GHG ≈ 5301 g CO₂e; Triple chip seal frequently attains the maximum normalized score across midpoint categories). However, when these values normalized per service year, Rubberized Chip Seal yields one of the lowest annual GHG burdens (≈177.5 g CO₂e/year), illustrating the trade-off between higher upfront material and installation impacts and longer service life. Monte Carlo uncertainty analysis (1000 runs, 95 % CI) confirms that the relative ranking of alternatives is robust. The results highlight clear cost–environment tradeoffs and the importance of life-span weighting in selecting preservation strategies.
本研究采用从摇篮到施工系统的边界，对7种切屑密封预防性维护方法（单、双、三重切屑密封、磨砂密封、角密封、纤维改性切屑密封和橡胶切屑密封）的生命周期评估和生命周期成本进行了比较分析。使用SimaPro v9 (Ecoinvent)，采用ReCiPe 2016 Endpoint (H)方法，对1 m²处理后的路面的功能单位进行了环境影响量化，并进行了经济分析，使用了记录的美国项目成本和伊朗价格表，并以10 %的折让率进行了年化。结果表明，在从支架到建筑的边界上，单片密封和磨砂密封的总标准化成本最低（分别为1.88和2.6美元/m2），而橡胶密封和三片密封的总标准化成本最高（分别为7.06和6.28美元/m2）。如果按使用寿命年化成本计算，单片密封和擦洗密封的成本最低（分别为0.5和0.69美元/平方米），而纤维密封、Cape密封和三片密封的成本最高（分别为1.03、1.05和1.05美元/平方米）。从环境的角度来看，Scrub Seal的温室气体总排放量最低（≈1545 g CO₂e），在人类健康、生态系统和资源方面的加权终点得分最低，而Cape Seal和Triple Chip Seal表现最差（Cape Seal的温室气体总排放量≈5301 g CO₂e； Triple Chip Seal经常在中点类别中获得最大的标准化得分）。然而，当这些值在每个使用年标准化时，橡胶屑密封产生的年温室气体负担最低（≈177.5 g CO₂e/年），说明了更高的前期材料和安装影响与更长的使用寿命之间的权衡。蒙特卡罗不确定性分析（1000次运行，95% CI）证实了备选方案的相对排名是稳健的。结果突出了明确的成本-环境权衡和寿命加权在选择保护策略中的重要性。
{"title":"Comparative life cycle assessment of chip seal preventive maintenance techniques: Cost and environmental implications","authors":"Farnaz Saadat, Mohammad Zia Alavi, Fateme Labbafi","doi":"10.1016/j.cscm.2025.e05663","DOIUrl":"10.1016/j.cscm.2025.e05663","url":null,"abstract":"<div><div>This study presents a comparative life cycle assessment and lifecycle cost analysis of seven chip-seal preventive maintenance treatments (Single, Double, and Triple chip seals; Scrub seal; Cape seal; Fiber-modified chip seal; and Rubberized chip seal) using a cradle-to-construction system boundary. Environmental impacts were quantified with SimaPro v9 (Ecoinvent) using the ReCiPe 2016 Endpoint (H) method for a functional unit of 1 m² of treated pavement and for the economic analysis, documented U.S. project costs and the Iranian price list were used and annualized with a 10 % discount rate. Results indicate that, under a cradle-to-construction boundary, Single Chip Seal and Scrub Seal have the lowest total normalized costs (1.88 and 2.6 USD/<span><math><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>), while Rubberized and Triple Chip Seals show the highest total costs (7.06 and 6.28 USD/<span><math><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>). When costs are annualized by service life, Single chip seal and Scrub seal remain the least costly (0.5 and 0.69 USD/<span><math><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>), whereas Fiber chip seal, Cape seal and Triple chip seal are the most expensive ones (1.03, 1.05, and 1.05, respectively). From an environmental standpoint, Scrub Seal has the lowest total GHG emissions (≈1545 g CO₂e) and the lowest weighted endpoint scores across Human Health, Ecosystems and Resources, whereas Cape Seal and Triple Chip Seal are the worst performers (Cape seal total GHG ≈ 5301 g CO₂e; Triple chip seal frequently attains the maximum normalized score across midpoint categories). However, when these values normalized per service year, Rubberized Chip Seal yields one of the lowest annual GHG burdens (≈177.5 g CO₂e/year), illustrating the trade-off between higher upfront material and installation impacts and longer service life. Monte Carlo uncertainty analysis (1000 runs, 95 % CI) confirms that the relative ranking of alternatives is robust. The results highlight clear cost–environment tradeoffs and the importance of life-span weighting in selecting preservation strategies.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05663"},"PeriodicalIF":6.6,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.cscm.2025.e05696
Jianchao Zhang , Hongxi Liu , Zejian Lin , Zhuang Li , Peng Dong , Yu Zheng
This study proposed a multi–objective optimization framework for designing self-compacting concrete (SCC) with tunable mechanical property, workability, and durability. Leveraging the non–dominated sorting genetic algorithm II (NSGA–II), three critical mixture parameters: fly ash incorporation (0–50 %, in relation to the cement content), sand content (7.6–8.8 kg), and water reducing agent (0.021–0.033 kg) were optimized to balance conflicting performance objectives. Experimental validation and microstructure analysis confirmed that a 34 % fly ash incorporation, 8.47 kg sand, and 0.0286 kg water reducing agent achieved optimal strength (74.83 MPa at 28 days), slump flow (730.88 mm), and low water absorption (1.36 %). The established optimization method effectively resolved tradeoffs, enabling tailored SCC designs for mechanical property–required, workability–critical, or durability–focused applications. The derived Pareto–optimal solutions provided context–dependent mixtures, demonstrating better performance improvements over conventional designs.
{"title":"Engineering high–performance SCC through multidimensional tradeoffs: Co–optimizing mechanical property, workability, and durability","authors":"Jianchao Zhang , Hongxi Liu , Zejian Lin , Zhuang Li , Peng Dong , Yu Zheng","doi":"10.1016/j.cscm.2025.e05696","DOIUrl":"10.1016/j.cscm.2025.e05696","url":null,"abstract":"<div><div>This study proposed a multi–objective optimization framework for designing self-compacting concrete (SCC) with tunable mechanical property, workability, and durability. Leveraging the non–dominated sorting genetic algorithm II (NSGA–II), three critical mixture parameters: fly ash incorporation (0–50 %, in relation to the cement content), sand content (7.6–8.8 kg), and water reducing agent (0.021–0.033 kg) were optimized to balance conflicting performance objectives. Experimental validation and microstructure analysis confirmed that a 34 % fly ash incorporation, 8.47 kg sand, and 0.0286 kg water reducing agent achieved optimal strength (74.83 MPa at 28 days), slump flow (730.88 mm), and low water absorption (1.36 %). The established optimization method effectively resolved tradeoffs, enabling tailored SCC designs for mechanical property–required, workability–critical, or durability–focused applications. The derived Pareto–optimal solutions provided context–dependent mixtures, demonstrating better performance improvements over conventional designs.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05696"},"PeriodicalIF":6.6,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.cscm.2025.e05690
Jaegon Lee, Heeyoung Lee
The cement industry accounts for approximately 7–8 % of global CO₂ emissions, emphasizing the urgent need for eco-friendly cementitious materials capable of reducing the sector’s carbon footprint. This study aims to develop sustainable cement composites by incorporating CO₂-sequestered precipitated calcium carbonate (PCC) as a supplementary cementitious material and by optimizing its particle size and replacement ratio to improve mechanical performance while minimizing environmental impact. To achieve this goal, 204 cement paste specimens were prepared using four PCC particle sizes (0.08, 0.1, 1.8, and 2.0 μm) and four replacement levels (5, 10, 15, and 20 %). Mechanical, microstructural, and thermal characteristics were investigated using compressive strength tests (ASTM C109), mercury intrusion porosimetry, digital image correlation, field-emission scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. The results reveal that compressive strength generally decreased with increasing PCC replacement. However, the mix containing 1.8 μm PCC at 5 % replacement achieved the highest strength (46.7 MPa, + 18.02 % relative to the control), accompanied by reduced pore volume and a more uniform strain distribution. These findings demonstrate that optimizing PCC particle size and dosage offers a novel, low-carbon pathway for achieving both mechanical improvement and CO₂ reduction. The proposed approach offers significant potential for the large-scale application of CO₂-sequestered PCC in carbon-neutral construction materials.
{"title":"Optimizing compressive strength in eco-friendly cement composites using CO₂-sequestered precipitated calcium carbonate by particle size and replacement ratio","authors":"Jaegon Lee, Heeyoung Lee","doi":"10.1016/j.cscm.2025.e05690","DOIUrl":"10.1016/j.cscm.2025.e05690","url":null,"abstract":"<div><div>The cement industry accounts for approximately 7–8 % of global CO₂ emissions, emphasizing the urgent need for eco-friendly cementitious materials capable of reducing the sector’s carbon footprint. This study aims to develop sustainable cement composites by incorporating CO₂-sequestered precipitated calcium carbonate (PCC) as a supplementary cementitious material and by optimizing its particle size and replacement ratio to improve mechanical performance while minimizing environmental impact. To achieve this goal, 204 cement paste specimens were prepared using four PCC particle sizes (0.08, 0.1, 1.8, and 2.0 μm) and four replacement levels (5, 10, 15, and 20 %). Mechanical, microstructural, and thermal characteristics were investigated using compressive strength tests (ASTM C109), mercury intrusion porosimetry, digital image correlation, field-emission scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. The results reveal that compressive strength generally decreased with increasing PCC replacement. However, the mix containing 1.8 μm PCC at 5 % replacement achieved the highest strength (46.7 MPa, + 18.02 % relative to the control), accompanied by reduced pore volume and a more uniform strain distribution. These findings demonstrate that optimizing PCC particle size and dosage offers a novel, low-carbon pathway for achieving both mechanical improvement and CO₂ reduction. The proposed approach offers significant potential for the large-scale application of CO₂-sequestered PCC in carbon-neutral construction materials.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05690"},"PeriodicalIF":6.6,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.cscm.2025.e05699
Kuangliang Qian , Lifeng Zhang , Chuangbo Miao , Chuang Qian , Tongfa Fan , Dongming Yan , Xiaoqian Qian
Manufactured sand derived from solid wastes has not yet been widely adopted in engineering applications such as railway construction. This study systematically investigated concretes of two strength grades prepared with manufactured sands from tunnel-excavated tuff muck and granite cutting waste. Workability, mechanical strength, shrinkage, and various durability properties were evaluated and compared with river sand concretes of identical mix proportions. Mercury intrusion porosimetry, thermogravimetric analysis, and scanning electron microscopy were employed to investigate pore structure, hydration, and the interfacial transition zone. The results show that manufactured sand concretes met workability requirements and achieved higher mechanical strength. The 7-day compressive strength increased by 2.3–21.7 % and tensile strength by 2.5–11.1 %, while the ultimate tensile strain remained nearly unchanged. They also exhibited improved resistance to freeze–thaw cycles, water penetration, carbonation, and chloride ingress compared with river sand concrete, as a result of refined pore structures, higher hydration degrees, and a denser interfacial transition zone. However, early-age shrinkage measured from the initial setting was 8.5–32.4 % higher than that of river sand concrete at 3 days, but after three days of adequate curing, long-term shrinkage decreased by 4.3–13.9 %, highlighting the importance of proper early curing to prevent shrinkage-induced cracking and maintain the benefits of enhanced strength and durability.
{"title":"The shrinkage and durability of concrete prepared with waste rock manufactured sand","authors":"Kuangliang Qian , Lifeng Zhang , Chuangbo Miao , Chuang Qian , Tongfa Fan , Dongming Yan , Xiaoqian Qian","doi":"10.1016/j.cscm.2025.e05699","DOIUrl":"10.1016/j.cscm.2025.e05699","url":null,"abstract":"<div><div>Manufactured sand derived from solid wastes has not yet been widely adopted in engineering applications such as railway construction. This study systematically investigated concretes of two strength grades prepared with manufactured sands from tunnel-excavated tuff muck and granite cutting waste. Workability, mechanical strength, shrinkage, and various durability properties were evaluated and compared with river sand concretes of identical mix proportions. Mercury intrusion porosimetry, thermogravimetric analysis, and scanning electron microscopy were employed to investigate pore structure, hydration, and the interfacial transition zone. The results show that manufactured sand concretes met workability requirements and achieved higher mechanical strength. The 7-day compressive strength increased by 2.3–21.7 % and tensile strength by 2.5–11.1 %, while the ultimate tensile strain remained nearly unchanged. They also exhibited improved resistance to freeze–thaw cycles, water penetration, carbonation, and chloride ingress compared with river sand concrete, as a result of refined pore structures, higher hydration degrees, and a denser interfacial transition zone. However, early-age shrinkage measured from the initial setting was 8.5–32.4 % higher than that of river sand concrete at 3 days, but after three days of adequate curing, long-term shrinkage decreased by 4.3–13.9 %, highlighting the importance of proper early curing to prevent shrinkage-induced cracking and maintain the benefits of enhanced strength and durability.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05699"},"PeriodicalIF":6.6,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.cscm.2025.e05689
Xiaoning Han , Zaiqiang Hu , Hongru Li , Chen Yu , Bobo Zhang , Yan Yin , Longfei Zhang
<div><div>Due to the high initial moisture content of tailings mud, the use of fiber-cement for solidification poses issues of low strength and poor durability. Superabsorbent polymer (SAP) has provided an opportunity to solve this problem because of their high water-absorbance characteristics. This study systematically investigated the influence of SAP on the strength and durability of fiber-cement-stabilized tailings mud (FCS tailings mud) through unconfined compression tests and dry<img>wet cycle tests. Based on the experimental results, a comprehensive parameter <span><math><msub><mrow><mi>C</mi></mrow><mrow><msub><mrow><mi>q</mi></mrow><mrow><mi>u</mi></mrow></msub></mrow></msub></math></span> and a durability parameter <span><math><msub><mrow><mi>R</mi></mrow><mrow><msub><mrow><mi>q</mi></mrow><mrow><mi>u</mi></mrow></msub></mrow></msub></math></span> were established for quantitative evaluation, which indicated that the mix proportion of 0.3 % SAP, 0.2 % fiber, and 12 mm fiber length was optimal. Under a fixed fiber content (0.2 %) and length (12 mm), an increase in SAP content from 0 % to 0.3 % resulted in an enhancement of 217.16 % in the initial strength and 244.46 % in the strength after the maximum number of cycles. The results demonstrate that SAP is effective in enhancing both the strength and durability of FCS tailings mud. Furthermore, a constitutive model accurately describing the stress-strain relationship of the stabilized material was developed. By introducing a degradation factor <em>D</em>, the initial strength was effectively correlated with the deteriorated strength, leading to the development of a strength prediction model that integrates both curing conditions and the number of cycles. Furthermore, ICP-MS analysis confirmed that the incorporation of SAP effectively suppressed the leaching of Cu, Zn, and Pb ions from the FCS tailings mud. Finally, through microscopic tests such as XRD, ESEM-EDS, and SEM, the reinforcement mechanism and the dry<img>wet cycle degradation mechanism of SAP-reinforced fiber-cement-stabilized tailings mud (SRFCS tailings mud) were revealed. The results indicate that during the curing process, in the specimen with an appropriate amount of SAP, SAP, by filling pores and regulating the internal humidity, provides a favorable environment for the enhancing effects of fiber and cement; however, in the specimen with excessive SAP, SAP increases the inter-particle spacing and weakens the fiber-soil interfacial bonding, consequently leading to a decrease in strength. During the dry<img>wet cycles, the specimen with an appropriate amount of SAP can, by regulating moisture migration, delay the rapid permeation and evaporation of water, and provide water for the continuous hydration of cement, thereby enhancing durability, which is specifically manifested as mesopores occupying the dominant position in the total pore area after cycling; conversely, in the specimen with an excessive amount of SAP, the uneve
{"title":"Investigation of the mechanical properties and microscopic mechanisms of fiber-cement-stabilized tailings mud reinforced with a superabsorbent polymer","authors":"Xiaoning Han , Zaiqiang Hu , Hongru Li , Chen Yu , Bobo Zhang , Yan Yin , Longfei Zhang","doi":"10.1016/j.cscm.2025.e05689","DOIUrl":"10.1016/j.cscm.2025.e05689","url":null,"abstract":"<div><div>Due to the high initial moisture content of tailings mud, the use of fiber-cement for solidification poses issues of low strength and poor durability. Superabsorbent polymer (SAP) has provided an opportunity to solve this problem because of their high water-absorbance characteristics. This study systematically investigated the influence of SAP on the strength and durability of fiber-cement-stabilized tailings mud (FCS tailings mud) through unconfined compression tests and dry<img>wet cycle tests. Based on the experimental results, a comprehensive parameter <span><math><msub><mrow><mi>C</mi></mrow><mrow><msub><mrow><mi>q</mi></mrow><mrow><mi>u</mi></mrow></msub></mrow></msub></math></span> and a durability parameter <span><math><msub><mrow><mi>R</mi></mrow><mrow><msub><mrow><mi>q</mi></mrow><mrow><mi>u</mi></mrow></msub></mrow></msub></math></span> were established for quantitative evaluation, which indicated that the mix proportion of 0.3 % SAP, 0.2 % fiber, and 12 mm fiber length was optimal. Under a fixed fiber content (0.2 %) and length (12 mm), an increase in SAP content from 0 % to 0.3 % resulted in an enhancement of 217.16 % in the initial strength and 244.46 % in the strength after the maximum number of cycles. The results demonstrate that SAP is effective in enhancing both the strength and durability of FCS tailings mud. Furthermore, a constitutive model accurately describing the stress-strain relationship of the stabilized material was developed. By introducing a degradation factor <em>D</em>, the initial strength was effectively correlated with the deteriorated strength, leading to the development of a strength prediction model that integrates both curing conditions and the number of cycles. Furthermore, ICP-MS analysis confirmed that the incorporation of SAP effectively suppressed the leaching of Cu, Zn, and Pb ions from the FCS tailings mud. Finally, through microscopic tests such as XRD, ESEM-EDS, and SEM, the reinforcement mechanism and the dry<img>wet cycle degradation mechanism of SAP-reinforced fiber-cement-stabilized tailings mud (SRFCS tailings mud) were revealed. The results indicate that during the curing process, in the specimen with an appropriate amount of SAP, SAP, by filling pores and regulating the internal humidity, provides a favorable environment for the enhancing effects of fiber and cement; however, in the specimen with excessive SAP, SAP increases the inter-particle spacing and weakens the fiber-soil interfacial bonding, consequently leading to a decrease in strength. During the dry<img>wet cycles, the specimen with an appropriate amount of SAP can, by regulating moisture migration, delay the rapid permeation and evaporation of water, and provide water for the continuous hydration of cement, thereby enhancing durability, which is specifically manifested as mesopores occupying the dominant position in the total pore area after cycling; conversely, in the specimen with an excessive amount of SAP, the uneve","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05689"},"PeriodicalIF":6.6,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-12DOI: 10.1016/j.cscm.2025.e05692
Jiahuan Yu, Yuhan Li, Song Huang
Research on steel pipe reinforced concrete has advanced significantly, yet its role in construction still requires more exploration. This study examines a new type of structure similar to steel pipe concrete columns, known as Oil-Filled Steel Pipe (OFST), which consist of circular steel tubes filled with anti-wear hydraulic oil. Despite being a derivative of steel, there is limited global research on these columns, with most studies focusing on their use in mechanical devices rather than as structural elements in buildings. Therefore, investigating OFST is highly relevant. This paper evaluates their axial compressive load capacity and analyzes steel pipe concrete structures to enhance understanding. Findings show that both the length and slenderness ratio of the columns significantly affect their load-bearing capacity, with increases in either reducing capacity. Additionally, a higher diameter-to-thickness ratio decreases axial pressure-bearing capacity, indicating that thicker walls enhance the load-bearing capacity. Notably, OFST have a higher load-bearing capacity than empty steel pipes when there is no internal pressure, but internal pressure reduces this capacity.
{"title":"Experimental study on axial compressive capacity of oil-filled steel pipe","authors":"Jiahuan Yu, Yuhan Li, Song Huang","doi":"10.1016/j.cscm.2025.e05692","DOIUrl":"10.1016/j.cscm.2025.e05692","url":null,"abstract":"<div><div>Research on steel pipe reinforced concrete has advanced significantly, yet its role in construction still requires more exploration. This study examines a new type of structure similar to steel pipe concrete columns, known as Oil-Filled Steel Pipe (OFST), which consist of circular steel tubes filled with anti-wear hydraulic oil. Despite being a derivative of steel, there is limited global research on these columns, with most studies focusing on their use in mechanical devices rather than as structural elements in buildings. Therefore, investigating OFST is highly relevant. This paper evaluates their axial compressive load capacity and analyzes steel pipe concrete structures to enhance understanding. Findings show that both the length and slenderness ratio of the columns significantly affect their load-bearing capacity, with increases in either reducing capacity. Additionally, a higher diameter-to-thickness ratio decreases axial pressure-bearing capacity, indicating that thicker walls enhance the load-bearing capacity. Notably, OFST have a higher load-bearing capacity than empty steel pipes when there is no internal pressure, but internal pressure reduces this capacity.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05692"},"PeriodicalIF":6.6,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-12DOI: 10.1016/j.cscm.2025.e05688
Joseph Pugh , Diane Gardner , Riccardo Maddalena
Waste Foundry Sand (WFS), a by-product of the cast metal industry is produced in quantities exceeding 100 million tons annually. Being a high-quality silica sand, it poses a potential solution for reuse within concrete as a fine aggregate replacement; simultaneously addressing the increasingly critical issue of foundry waste generation and mitigating the overextraction of natural aggregates for concrete production in line with United Nations Sustainable Development Goals. It is widely understood that partial WFS substitution as a fine aggregate within concrete is not only acceptable but often beneficial, however the variability in the properties of WFS concrete has yet to be systematically tracked and categorised. This state-of the-art-review provides a succinct and detailed assessment of the typical impact of WFS on concrete performance, highlighting variability in properties, and recent advancements for optimisation. Analysis of the lesser examined facets, such as WFS treatment and combination with supplementary cementitious materials is undertaken to provide a robust methodology for WFS concrete optimisation via effective research collation and impact categorisation. Existing studies on long-term durability, and life cycle assessment in terms of both environment and economics, are highlighted as lacking comprehensive insight and thus create a framework for future research.
{"title":"A state-of-the-art review of Waste Foundry Sand concrete from an optimisation perspective","authors":"Joseph Pugh , Diane Gardner , Riccardo Maddalena","doi":"10.1016/j.cscm.2025.e05688","DOIUrl":"10.1016/j.cscm.2025.e05688","url":null,"abstract":"<div><div>Waste Foundry Sand (WFS), a by-product of the cast metal industry is produced in quantities exceeding 100 million tons annually. Being a high-quality silica sand, it poses a potential solution for reuse within concrete as a fine aggregate replacement; simultaneously addressing the increasingly critical issue of foundry waste generation and mitigating the overextraction of natural aggregates for concrete production in line with United Nations Sustainable Development Goals. It is widely understood that partial WFS substitution as a fine aggregate within concrete is not only acceptable but often beneficial, however the variability in the properties of WFS concrete has yet to be systematically tracked and categorised. This state-of the-art-review provides a succinct and detailed assessment of the typical impact of WFS on concrete performance, highlighting variability in properties, and recent advancements for optimisation. Analysis of the lesser examined facets, such as WFS treatment and combination with supplementary cementitious materials is undertaken to provide a robust methodology for WFS concrete optimisation via effective research collation and impact categorisation. Existing studies on long-term durability, and life cycle assessment in terms of both environment and economics, are highlighted as lacking comprehensive insight and thus create a framework for future research.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"24 ","pages":"Article e05688"},"PeriodicalIF":6.6,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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