Case Studies in Construction Materials最新文献

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Study on flexural behavior of CO2 cured recycled coarse aggregate concrete steel bar trusses composite slab CO2固化再生粗骨料混凝土钢筋桁架组合板抗弯性能研究
IF 6.5 2区 工程技术
Case Studies in Construction Materials Pub Date : 2025-06-19 DOI: 10.1016/j.cscm.2025.e04940
Yueqing Gao , Sijie Shen , Ke Ye , Zeshen Li , Wei Wang , Jingyi Lu , Shaodan Hou , Yangyang Yin , Chaofeng Liang
{"title":"Study on flexural behavior of CO2 cured recycled coarse aggregate concrete steel bar trusses composite slab","authors":"Yueqing Gao ,&nbsp;Sijie Shen ,&nbsp;Ke Ye ,&nbsp;Zeshen Li ,&nbsp;Wei Wang ,&nbsp;Jingyi Lu ,&nbsp;Shaodan Hou ,&nbsp;Yangyang Yin ,&nbsp;Chaofeng Liang","doi":"10.1016/j.cscm.2025.e04940","DOIUrl":"10.1016/j.cscm.2025.e04940","url":null,"abstract":"<div><div>The effects of aggregate carbonation, overall specimen carbonation, and the combined method of aggregate carbonation and overall specimen carbonation on the mechanical properties of recycled coarse aggregate concrete (RAC) were investigated. Furthermore, the flexural behaviors of steel bar trusses composite slab (SBTCS) prepared by RAC and cured by the three carbonation methods were studied through experiments and numerical analysis. The results indicated that: (1) The mechanical properties of RAC after carbonation were significantly improved, and the concrete prepared by the combined method of aggregate carbonation and overall specimen carbonation showed the highest strength. (2) The stress-strain constitutive models of RAC under different carbonation methods were built according to the experimental results. (3) The failure modes of the carbonated concrete SBTCSs were basically consistent and the precast layer and the cast-in-situ layer deformed coordinately during the loading process. (4) The SBTCS prepared by the combined method of aggregate carbonation and overall specimen carbonation showed the best bending performance, and the ultimate load bearing capacity increased by 16.2 % compared to the SBTCS made by non-carbonated RAC. (5) The load-displacement curves and damage contours of the SBTCSs obtained from the numerical analysis were in good agreement with the experimental results, and the maximum deviation between the simulated ultimate load and the experimental value was 8.8 %.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"23 ","pages":"Article e04940"},"PeriodicalIF":6.5,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144335824","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}
引用次数: 0
Synthesis and characteristic of decomposed products from recycled concrete fines by acetic acid decomposition treatment 再生混凝土细粒醋酸分解产物的合成及特性研究
IF 6.5 2区 工程技术
Case Studies in Construction Materials Pub Date : 2025-06-18 DOI: 10.1016/j.cscm.2025.e04950
Chen Chen , Liguo Wang , Shiyu Sui , Fengjuan Wang , Qi Zheng , Jinyang Jiang
{"title":"Synthesis and characteristic of decomposed products from recycled concrete fines by acetic acid decomposition treatment","authors":"Chen Chen ,&nbsp;Liguo Wang ,&nbsp;Shiyu Sui ,&nbsp;Fengjuan Wang ,&nbsp;Qi Zheng ,&nbsp;Jinyang Jiang","doi":"10.1016/j.cscm.2025.e04950","DOIUrl":"10.1016/j.cscm.2025.e04950","url":null,"abstract":"<div><div>In this work, an acetic acid decomposition method was proposed to synthesize amorphous nano-silica and calcium acetate rich solution from the recycled concrete fines (RCF), waste concrete with the aggregates removed, which realized the conversion of RCF into high value-added products by separating and purifying the phases of calcium and silicon. Characterization was carried out by means of thermogravimetry, Fourier transformation-infrared spectroscopy, electron microscope, <sup>29</sup>Si Solid-state nuclear magnetic resonance and BET method to better investigate the phases assemblage evolution and their microstructure development during decomposition systematically. The results indicated that the RCF was decomposed rapidly to generate amorphous silica bearing gel. A purified amorphous nano-silica gel was successfully prepared with high porosity, high polymerization degree and high purity up to 99.3 %. And a calcium acetate rich solution was obtained as well. Both decomposed products have proved to be beneficial to the cementitious material system. The work provides technical and theoretical support for the complete and efficient reuse of the recycled cementitious material system during the later stages.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"23 ","pages":"Article e04950"},"PeriodicalIF":6.5,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329929","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}
引用次数: 0
The influence mechanism of wet-ground ultra-fine granulated blast furnace slag on the shrinkage cracking sensitivity of cementitious materials based on the eccentric ring test 基于偏心环试验研究湿磨超细粒化高炉渣对胶凝材料收缩开裂敏感性的影响机理
IF 6.5 2区 工程技术
Case Studies in Construction Materials Pub Date : 2025-06-18 DOI: 10.1016/j.cscm.2025.e04942
Cong Tian , Nan Chen , Xingyang He , Can Mei , Ying Su , Liang Xiong , Xingyuan Ma , Zhengqi Zheng
{"title":"The influence mechanism of wet-ground ultra-fine granulated blast furnace slag on the shrinkage cracking sensitivity of cementitious materials based on the eccentric ring test","authors":"Cong Tian ,&nbsp;Nan Chen ,&nbsp;Xingyang He ,&nbsp;Can Mei ,&nbsp;Ying Su ,&nbsp;Liang Xiong ,&nbsp;Xingyuan Ma ,&nbsp;Zhengqi Zheng","doi":"10.1016/j.cscm.2025.e04942","DOIUrl":"10.1016/j.cscm.2025.e04942","url":null,"abstract":"<div><div>Improving the hydration activity of supplementary cementitious materials (SCMs) through ultra-refinement to enhance their application in concrete is a critical development direction for achieving both low carbon emissions and high performance. However, ultrafine SCMs may reduce workability and increase risk of early shrinkage cracking of cementitious materials. In this research, ordinary and wet-ground ultra-fine granulated blast furnace slag (WGGBS) were selected as the subjects of study. The shrinkage and cracking performance of the two types of ultra-fine GGBS cementitious materials were characterized by the eccentric ring test. The cracking risk at various positions of the eccentric ring specimen was analyzed through theoretical analysis in the bipolar coordinate system. The effect of ultra-fine GGBS dosage on the hydration and pore structure of the cementitious materials was clarified. The results indicate that both types of ultrafine GGBS can accelerate the hydration of cement and promote the rapid refinement of pore structure, leading to an increase in the autogenous shrinkage of cementitious materials. Conversely, WGGBS cementitious materials exhibit lower porosity, improved water retention, and greater compressive strength at 7 days. WGGBS significantly reduces drying shrinkage and extends both the initial cracking and through-cracking times. The autogenous and drying shrinkage of cementitious materials are less sensitive to the content of WGGBS compared to OGGBS. WGGBS demonstrates more pronounced advantages in enhancing mechanical strength and crack resistance. This study provides theoretical support for the coordinated optimization of mechanical strength and resistance to shrinkage cracking in cementitious materials prepared with ultra-fine GGBS.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"23 ","pages":"Article e04942"},"PeriodicalIF":6.5,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338838","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}
引用次数: 0
Electrical conduction model and equivalent circuit of cementitious composites containing nano additives 含纳米添加剂胶凝复合材料的导电模型及等效电路
IF 6.5 2区 工程技术
Case Studies in Construction Materials Pub Date : 2025-06-18 DOI: 10.1016/j.cscm.2025.e04952
Yunyang Wang , Sha Liu , Liqing Zhang , Shengwei Sun , Chenggong Zhao , Yonghui Qin
{"title":"Electrical conduction model and equivalent circuit of cementitious composites containing nano additives","authors":"Yunyang Wang ,&nbsp;Sha Liu ,&nbsp;Liqing Zhang ,&nbsp;Shengwei Sun ,&nbsp;Chenggong Zhao ,&nbsp;Yonghui Qin","doi":"10.1016/j.cscm.2025.e04952","DOIUrl":"10.1016/j.cscm.2025.e04952","url":null,"abstract":"<div><div>Electrical conductivity cementitious composites have advantages of superior electrical conductivity, favorable mechanical property, possessing multifunctionality, thus, exhibiting widely prospect in intelligent civil infrastructures. In this paper, the cementitious composites containing the hybrid carbon nano tubes (CNTs) and nano carbon blacks (NCBs) are prepared firstly. And then, the CNTs and NCBs with dosages variation from 0.0 to 5.0 vol% effect on electrical conduction of the composites are systematically investigated. Finally, the electrical conduction model combination with equivalent circuit is proposed to explore the electrical conduction mechanisms in-depth. Results show that the electrical resistivity of the composites is reduced up to three orders of magnitude with increasing concentration of the CNTs and NCBs, and the relationship between electrical conductivity and content of the CNTs and NCBs follows the percolation theory. The electrical conduction features can be precisely explained using the proposed electrical conduction model accompanies with equivalent circuit. The originality of the present study is proposed the electrical conduction model and equivalent circuit of the cementitious composites containing the hybrid CNTs and NCBs. Therefore, the findings of the present research will pave an extensive path for utilization of electrical conductivity cementitious composites in developing multifunctional civil infrastructures.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"23 ","pages":"Article e04952"},"PeriodicalIF":6.5,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144364390","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}
引用次数: 0
Experimental study and machine learning prediction on compressive strength of industrial waste- solidified marine soft soil under dry-wet cycles 干湿循环下工业废土固化海洋软土抗压强度试验研究及机器学习预测
IF 6.5 2区 工程技术
Case Studies in Construction Materials Pub Date : 2025-06-18 DOI: 10.1016/j.cscm.2025.e04943
Yi-dan Sun , Chao Li , Qiu-yang Bi , Jia-wei Li , Jin-liang Zhang , Xiao-yu Lu , Yu Yang
{"title":"Experimental study and machine learning prediction on compressive strength of industrial waste- solidified marine soft soil under dry-wet cycles","authors":"Yi-dan Sun ,&nbsp;Chao Li ,&nbsp;Qiu-yang Bi ,&nbsp;Jia-wei Li ,&nbsp;Jin-liang Zhang ,&nbsp;Xiao-yu Lu ,&nbsp;Yu Yang","doi":"10.1016/j.cscm.2025.e04943","DOIUrl":"10.1016/j.cscm.2025.e04943","url":null,"abstract":"<div><div>The rapid development of infrastructure in coastal regions has led to the deterioration of soil mechanical properties due to dry-wet (D-W) cycles, which significantly affects the durability of engineering projects. While most previous studies have focused on the impact of curing agents on the mechanical properties of marine soft soil (MSS), a systematic framework for predicting the strength of stabilized materials under D-W cycles is still lacking. To address this gap, this study utilizes blast furnace slag (GGBS), fly ash (FA), and lime in combination to improve MSS. A database containing 624 Unconfined compressive strength (UCS) data points was established to study the strength characteristics and curing mechanism of solidified Marine silt (LGF-MSS) under D-W cycles, and the optimal content of curing agent was determined. Using the XGBoost machine learning framework, optimization algorithms including the Whale Optimization Algorithm, Particle Swarm Optimization, Sparrow Search Algorithm, Grey Wolf Optimization, and Firefly Optimization Algorithm were applied to develop a UCS prediction model under D-W conditions. The SSA-XGBoost model achieves optimal performance in UCS prediction, with a coefficient of determination (R²) of 0.9786 on the test set. In addition, the study provides the importance of curing age, LGF content, number of cycles, degree of compaction, and drying temperature by using correlation analysis, sensitivity analysis, and SHapley Additive exPlanations (SHAP). The developed high-precision prediction model effectively predicts the strength of LGF-MSS under D-W cycles, offering strong technical support and decision-making references for related engineering practices.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"23 ","pages":"Article e04943"},"PeriodicalIF":6.5,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329931","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}
引用次数: 0
Phased array ultrasonic and deep learning based internal defect detection in underwater concrete bridge structures 基于相控阵超声和深度学习的水下混凝土桥梁结构内部缺陷检测
IF 6.5 2区 工程技术
Case Studies in Construction Materials Pub Date : 2025-06-17 DOI: 10.1016/j.cscm.2025.e04946
Weihao Sun , Shitong Hou , Gang Wu , Zhishen Wu , Wen Xiong , Jian Zhang
{"title":"Phased array ultrasonic and deep learning based internal defect detection in underwater concrete bridge structures","authors":"Weihao Sun ,&nbsp;Shitong Hou ,&nbsp;Gang Wu ,&nbsp;Zhishen Wu ,&nbsp;Wen Xiong ,&nbsp;Jian Zhang","doi":"10.1016/j.cscm.2025.e04946","DOIUrl":"10.1016/j.cscm.2025.e04946","url":null,"abstract":"<div><div>Underwater concrete structures, which are critical load-bearing components in water-crossing bridges, are often prone to internal defects that undermine their long-term integrity. Traditional inspection methods, which mainly focus on surface defects, fall short in detecting internal structural issues, creating a significant gap in maintenance and safety assessments. This study proposes a phased array ultrasonic testing (PAUT) and deep learning based internal defect detection method in underwater concrete bridges. First, a new underwater PAUT device is developed, incorporating non-local means filtering to reduce noise and enhance ultrasonic imaging quality. Second, a small-scale dataset of ultrasonic images depicting internal defects in underwater concrete is created, and StyleGAN2-ADA was employed for effective data augmentation, addressing the challenge of limited data availability. To further improve defect detection, an enhanced SAM-based method is introduced, utilizing both serial and parallel depth-wise adapter fine-tuning strategies, which significantly boost the model's adaptability to complex underwater ultrasonic imaging tasks. Additionally, a pyramid-module-based self-generating prompt encoder is developed to optimize feature extraction and reduce manual intervention. Experimental results on both laboratory specimens and real-world underwater bridge piers demonstrate the superior performance of this method. The detection model achieves an Intersection over Union (IoU) score of 0.772—an improvement of 4.49 % over the baseline SAM model—and outperforms other approaches in precision, recall, and F1-score. This research presents a robust, efficient, and scalable solution for internal defect detection in underwater concrete bridge structures, with strong potential for real-world applications in structural health monitoring.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"23 ","pages":"Article e04946"},"PeriodicalIF":6.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144321630","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}
引用次数: 0
Iron tailing powder in cement-based composites: Evaluating filling effect from particle-size distribution 铁尾矿粉在水泥基复合材料中的应用:从粒径分布评价充填效果
IF 6.5 2区 工程技术
Case Studies in Construction Materials Pub Date : 2025-06-17 DOI: 10.1016/j.cscm.2025.e04919
Mingjing Yang, Jianheng Sun, Jing Yuan, Hongbin Li, Da Xu, Ruolan Zhang, Xinrui Ma
{"title":"Iron tailing powder in cement-based composites: Evaluating filling effect from particle-size distribution","authors":"Mingjing Yang,&nbsp;Jianheng Sun,&nbsp;Jing Yuan,&nbsp;Hongbin Li,&nbsp;Da Xu,&nbsp;Ruolan Zhang,&nbsp;Xinrui Ma","doi":"10.1016/j.cscm.2025.e04919","DOIUrl":"10.1016/j.cscm.2025.e04919","url":null,"abstract":"<div><div>Iron tailings, a significant hazardous waste, can be put to use as mineral admixtures in concrete, but the mechanism by which they function requires elucidation. In this study, we define a filling-effect coefficient <em>δ</em> for iron tailing powder (ITP) based on the Horsfield and Andreasen closest-packing theories. Four intervals of the particle size are selected to show how the distribution of ITP affects the pore structure of cement-based composites (CBCs). Experimental measurements of the activity of ITP show that by using <em>δ</em>, the activity indices of ITPs with different fineness values can be calculated without time-consuming mortar tests. Our analysis indicates that ITP particle sizes &lt; 5 µm are essential for the filling effect. However, the contribution of the filling effect to the activity index is limited: Excessive increase in the fineness of ITP does not further enhance their activity. The overall correlation coefficient between <em>δ</em> and the 28 d activity index of ITP with different fineness values is 0.9076. An evaluation formula of the activity index of ITP is established to quantitatively calculate the activity index of ITP with different fineness without mortar test.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"23 ","pages":"Article e04919"},"PeriodicalIF":6.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144321631","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}
引用次数: 0
Optimization and utilization of air-entrained recycled brick aggregate concrete under freeze-thaw environment 冻融环境下掺气再生砖骨料混凝土的优化利用
IF 6.5 2区 工程技术
Case Studies in Construction Materials Pub Date : 2025-06-17 DOI: 10.1016/j.cscm.2025.e04941
Muhammad Atasham ul haq , Peng Wang , Yaocheng Wang , Hongzhi Cui , Muhammad Tahir , Fuyuan Gong , Weiwen Li
{"title":"Optimization and utilization of air-entrained recycled brick aggregate concrete under freeze-thaw environment","authors":"Muhammad Atasham ul haq ,&nbsp;Peng Wang ,&nbsp;Yaocheng Wang ,&nbsp;Hongzhi Cui ,&nbsp;Muhammad Tahir ,&nbsp;Fuyuan Gong ,&nbsp;Weiwen Li","doi":"10.1016/j.cscm.2025.e04941","DOIUrl":"10.1016/j.cscm.2025.e04941","url":null,"abstract":"<div><div>Utilizing recycled brick aggregate (RBA) offers a sustainable solution to the environmental challenges posed by construction and demolition waste (CDW). However, the high water absorption and porosity of RBA accelerate freeze-thaw (FT) damage, leading to significant deterioration of both the aggregate and the concrete matrix, which compromises structural integrity. While air-entrainment has proven effective for natural and recycled concrete aggregate concrete, its application to recycled brick aggregate concrete (RBAC) remains unexplored. This study investigates the effectiveness of air-entrainment in enhancing the FT resistance of RBAC. Twelve air-entrained RBAC mixtures with varying w/c ratios (0.55, 0.45, and 0.35) and RBA substitution levels (0 %, 25 %, 50 %, and 100 %) were prepared and subjected to 300 rapid FT cycles. The results showed that RBA has a detrimental effect on the FT resistance of RBAC despite air-entrainment as evidenced by the increased mass loss, reduced RDME, and reduction in compressive strength. However, the combination of air-entrainment with low w/c ratio effectively moderated internal deterioration caused by ice expansion during FT cycling. Mercury intrusion porosimetry (MIP) analysis showed similar alteration in pore size distribution between the 0.35A-RBA-0 and 0.35A-RBA-100 specimen after FT cycling, while RBAC specimens with 0.45 and 0.55 w/c ratio showed significant expansion of mesopores and macropores (harmful pores &gt;100 nm). X-ray computed tomography (XCT) analysis confirmed that air-entrainment preserved the mortar matrix from cracking despite localized RBA cracking at low w/c ratio. The developed FT damage model confirmed up to 46 % reduction in service life of RBAC compared to NAC, depending on w/c ratio. Therefore, it is recommended to limit the RBA content to 50 % while maintaining low w/c ratio at or below 0.45, particularly in cold regions where FT resistance is critical. These findings establish guidelines for optimizing RBAC mix design under cold climates, advancing sustainability and promoting circular economy practices in the construction sector.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"23 ","pages":"Article e04941"},"PeriodicalIF":6.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144313461","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}
引用次数: 0
Evaluation of compressive strength of eco-friendly cementitious composites incorporating waste oyster shells under sodium chloride solution exposure 含废牡蛎壳的环保胶凝复合材料在氯化钠溶液下的抗压强度评价
IF 6.5 2区 工程技术
Case Studies in Construction Materials Pub Date : 2025-06-17 DOI: 10.1016/j.cscm.2025.e04944
Jinwoong Kim, Inyeong Cha, Byungkyu Jo, Heeyoung Lee
{"title":"Evaluation of compressive strength of eco-friendly cementitious composites incorporating waste oyster shells under sodium chloride solution exposure","authors":"Jinwoong Kim,&nbsp;Inyeong Cha,&nbsp;Byungkyu Jo,&nbsp;Heeyoung Lee","doi":"10.1016/j.cscm.2025.e04944","DOIUrl":"10.1016/j.cscm.2025.e04944","url":null,"abstract":"<div><div>The development of the marine industry and the continuous increase in oyster production have caused the accumulation of large quantities of waste oyster shells, with only a small portion being recycled. Unrecycled waste oyster shells cause environmental problems, produce odors, and harm marine ecosystems. Simultaneously, aggregates such as sand are in high demand in the construction industry. Waste oyster shells, primarily comprising calcium carbonate (CaCO₃), have similar material characteristics to sand and can be used as a sand substitute. In this study, oyster shell cementitious composites were produced to assess the potential of waste oyster shells as a sand replacement. The experimental parameters included the use of admixtures, curing in either fresh water or sodium chloride solution, and various curing durations. The specimens were cured for 91 days in fresh water and 30, 60, or 91 days in sodium chloride solution. Nine oyster shell cementitious composite specimens measuring 50 mm × 50 mm × 50 mm were fabricated for each experimental condition, resulting in a total of 144 specimens. When cured in sodium chloride solution, the compressive strength decreased as the curing time increased, while the compressive strengths cured in fresh water and sodium chloride solution for 91 days were 38.8 and 34.55 MPa, respectively. Thus, the specimens cured in sodium chloride solution retained more than 80 % of the strength of those cured in fresh water. Therefore, waste oyster shells can serve as an eco-friendly construction material and are a viable alternative to sand.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"23 ","pages":"Article e04944"},"PeriodicalIF":6.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329932","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}
引用次数: 0
Shear behavior of environmentally friendly rubberized RC beams externally strengthened with side-bonded prefabricated SHCC plates 边粘结预制SHCC板外加固环保型橡胶RC梁的抗剪性能
IF 6.5 2区 工程技术
Case Studies in Construction Materials Pub Date : 2025-06-16 DOI: 10.1016/j.cscm.2025.e04936
Mohamed Ghalla , Mohamed H. El-Naqeeb , Weiwen Li , Peng Wang , Walid Mansour , Taher A. Tawfik
{"title":"Shear behavior of environmentally friendly rubberized RC beams externally strengthened with side-bonded prefabricated SHCC plates","authors":"Mohamed Ghalla ,&nbsp;Mohamed H. El-Naqeeb ,&nbsp;Weiwen Li ,&nbsp;Peng Wang ,&nbsp;Walid Mansour ,&nbsp;Taher A. Tawfik","doi":"10.1016/j.cscm.2025.e04936","DOIUrl":"10.1016/j.cscm.2025.e04936","url":null,"abstract":"<div><div>This research proposes a sustainable solution for discarded tire disposal by repurposing rubber as a sand replacement in concrete mixtures for reinforced concrete (RC) beams. Furthermore, it examines the strengthening of rubberized beams using prefabricated strain-hardening cementitious composite (SHCC) plates to mitigate potential reductions in ultimate load or ductility caused by rubber incorporation in the concrete mixture. An experimental program was designed, consisting of 16 half-scale RC beams with shear deficiencies tested under three-point loading. The program investigates the effect of replacing sand with recycled rubber at proportions of 10 %, 30 %, and 50 %. Additionally, it examines the arrangement of the strengthening plates, either vertical or inclined at a 45° to the beam axis, as well as the fixation method, using either epoxy alone or a combination of epoxy and 10 mm steel anchors. The results indicate that vertical and inclined SHCC plates, fixed with epoxy alone, enhanced the ultimate load of rubberized beams containing 10 % rubber by 5 % and 16 %, respectively, compared to the reference beam cast entirely with sand. Furthermore, the beam cast with 10 % rubber and strengthened with inclined plates fixed using both epoxy and steel anchors exhibited the highest increase in ultimate load and ductility among the tested specimens, with improvements of 32 % and 85 %, respectively, relative to the reference beam. In addition to the experimental program, this study develops an analytical model to predict the ultimate load of rubberized beams strengthened with SHCC plates, considering the rubber content, the arrangement of the strengthening plates, and the fixation method.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"23 ","pages":"Article e04936"},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144313465","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}
引用次数: 0
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