Case Studies in Construction Materials最新文献

{"title":"Preliminary assessment of structural masonry damage in Malbork Castle","authors":"Krzysztof Grzyb ,&nbsp;Łukasz Drobiec ,&nbsp;Jakub Zając ,&nbsp;Kacper Drobiec","doi":"10.1016/j.cscm.2024.e04166","DOIUrl":"10.1016/j.cscm.2024.e04166","url":null,"abstract":"<div><div>The castle in Malbork is one of the most representative brick buildings in the world and an excellent example of medieval defensive and residential architecture in Central Europe. This facility is a top-class monument, as evidenced by its inclusion on the UNESCO World Heritage List. Although it might seem that the subsoil is consolidated within the castle and no new cracks should be visible in the masonry structure - recent years have shown that the facility still requires both systematic monitoring of displacements and comprehensive structural diagnostics. Damage was observed in the Palace of the Grand Masters, particularly on the eastern wall and the barrel and palm vaults. The paper presents a preliminary analysis of palace damage and observed cracks. The assessment of the technical condition of the walls and the causes of the structural irregularities was carried out based on local inspections and tests of the structure, including geodetic measurements, ultrasonic tomograph tests and geophysical tests performed using the GPR method using the short-offset reflective profiling (GPR) technique. Additionally, destructive tests were also performed by drilling holes in the basement floor with the introduction of an inspection camera. It was found that the cause of the damage was uneven settlement of the subsoil. Additionally, it was found that there is probably a previously undiscovered brick vault below the basement floor, where visual inspection holes have been made.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04166"},"PeriodicalIF":6.5,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical properties and microstructure of low carbon high-strength engineered cementitious composites with supplementary cementitious material","authors":"Shuangquan Qing ,&nbsp;Chuanxi Li","doi":"10.1016/j.cscm.2024.e04164","DOIUrl":"10.1016/j.cscm.2024.e04164","url":null,"abstract":"<div><div>The carbon emissions associated with concrete production remain a significant unresolved issue. One effective approach to mitigate this problem is to partially substitute cement with supplementary cementitious materials. The aim of the present study was to develop low-carbon, high-strength Engineered Cementitious Composites (HSECC) by incorporating low-hydration active solid waste in the form of coal gangue powder. To investigate the mechanical properties and underlying microscopic mechanisms of these composites, comprehensive testing was conducted, including assessments of compressive strength, tensile strength, single-crack tensile behaviour, three-point flexural performance, and scanning electron microscopy. The test results reveal that the integrity of the damaged compressive specimen was high. Compared with the test group without coal gangue powder, the incorporation of coal gangue powder significantly reduced the compressive strength, decreasing by 27.2 % and 32.5 %, respectively. The tensile strain hardening phenomenon appeared in all experimental groups. The inclusion of an optimal amount of coal gangue powder enhanced the tensile strain capacity, with the maximum tensile strain capacity reaching 4.15 %. Increasing fibre length substantially reduced crack width; for instance, the crack width in the 18 mm fibre test group was 31μm, which is only 33.6 % of the crack width observed in the 12 mm fibre group. Additionally, the incorporation of coal gangue powder significantly contributed to the reduction of crack width. In the context of embodied energy and embodied carbon in HSECC, PVA fibres and cement were found to be the primary contributors. Substituting a portion of the cement with coal gangue powder and silica powder significantly reduced both embodied energy and embodied carbon. The present study provides a novel utilisation method for coal gangue, a solid waste byproduct, which significantly mitigates its environmental impact. Additionally, the high-strength ECC produced using exclusively local materials demonstrates potential for broader implementation, particularly in applications such as concrete for bridge expansion joint anchorage zones and seismic retrofitting of external masonry walls.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04164"},"PeriodicalIF":6.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning-based modelling and analysis of carbonation depth of recycled aggregate concrete","authors":"Xuyong Chen ,&nbsp;Xuan Liu ,&nbsp;Shukai Cheng ,&nbsp;Xiaoya Bian ,&nbsp;Xixuan Bai ,&nbsp;Xin Zheng ,&nbsp;Xiong Xu ,&nbsp;Zhifeng Xu","doi":"10.1016/j.cscm.2024.e04162","DOIUrl":"10.1016/j.cscm.2024.e04162","url":null,"abstract":"<div><div>This paper used machine learning to model the prediction of carbonation depth and the analysis of feature parameters for recycled aggregate concrete (RAC). Specifically, a database containing 579 sets of RAC carbonation test data was developed. Twelve parameters representing material characteristics and environmental conditions were input, along with one output parameter. On this basis, six machine learning models were employed to predict RAC carbonation depth: Artificial Neural Network, Decision Tree, Support Vector Regression, Random Forest, Extreme Gradient Boosting, and Light Gradient Boosting. Different types of analysis, including statistical measures, shapley additive explanations (SHAP) sensitivity analysis, SHAP parametric study, and comparison study, were used to examine the performance of the developed models and the effects of the input parameters on predictions. The results show that the extreme gradient boosting (XGB) model exhibited the highest accuracy with an R² of 0.99 and a mean absolute percentage error (MAPE) of 6.632 on the training set, and an R² of 0.953 and a MAPE of 13.243 on the test set. The variable importance analysis shows that the carbonation depth for RAC was determined by both internal and external factors. The top five factors impacting RAC carbonation depth are exposure time, water-to-binder ratio, CO₂ concentration, coarse aggregate density, and cement content. RAC carbonation depth correlates positively with the former three factors. In contrast, it exhibits a negative correlation with the remaining two variables. In addition, a graphical user interface (GUI) for RAC carbonation depth prediction was designed.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04162"},"PeriodicalIF":6.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of severe environment and radiation on the behavior of cementitious materials modified by CKD and GBFS","authors":"Youssef Ahmed Awad ,&nbsp;Rafik K. Abdel Wahab ,&nbsp;Ahmed Deifalla ,&nbsp;Denise-Penelope N. Kontoni ,&nbsp;Mohamed Ehab","doi":"10.1016/j.cscm.2024.e04163","DOIUrl":"10.1016/j.cscm.2024.e04163","url":null,"abstract":"<div><div>Although concrete has many advantages as a construction material under normal settings, its behavior under extreme conditions has yet to be fully investigated, particularly with new advances in concrete technology and the need to create sustainable concrete. This study looks at the strength of modified cementitious materials in harsh situations. This study looks at the strength of modified cementitious materials in harsh situations. To test strength during sodium chloride exposure (5 % and 15 %) and radiation (80, 238, 356, 662, 1173, 1333, and 2164 keV), 62 specimens were manufactured with various concentrations of Granulated Blast Furnace Slag (GBFS) (10 %, 20 % and 30 %) and Cement Kiln Dust (CKD) (50 % and 100 %). The results show that GBFS-modified materials outperformed CKD. Specimens treated to 15 % sodium chloride showed a greater loss in strength than those exposed to 5 % sodium chloride. Cementitious materials changed with GBFS are more resistant to salts (sodium chloride) than those modified with CKD. Cementitious materials with GBFS demonstrated better gamma-ray shielding properties for CKD in the half value layers \"HVL\" and tenth value layers \"TVL\". Increasing thickness has no significant influence on the Linear Attenuation Coefficient.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04163"},"PeriodicalIF":6.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chloride threshold level determination: Call for test standardization to limit variations in experimental methodology and resolve inherent experimental and modelling detection challenges","authors":"Nicolas Maamary ,&nbsp;Ibrahim G. Ogunsanya","doi":"10.1016/j.cscm.2024.e04167","DOIUrl":"10.1016/j.cscm.2024.e04167","url":null,"abstract":"<div><div>Chloride-induced corrosion significantly threatens the durability of reinforced concrete structures, leading to deterioration, costly repairs, and potential structural failures. Accurately determining the steel reinforcing bar (rebar) chloride threshold level (CTL) is crucial for predicting corrosion onset, optimizing material selection, and estimating the service life of these structures. An ensemble machine learning model was trained using literature CTL data. Despite achieving a mean absolute error of 0.218 % weight of binder, a root mean square error of 0.321 % weight of binder, and an R² value of 0.751 on unseen data, the model's performance reveals limitations due to the wide variability in reported CTL, stemming from disparities in experimental methodologies including set-up and corrosion detection techniques. After model development, this paper also investigates challenges associated with CTL evaluation by comparing literature practices and providing insights to enhance data reliability and comparability. Factors impacting CTL evaluation includes corrosion detection techniques, initiation criteria, chloride introduction methods, testing setup, exposure solution compositions, chloride concentration measurement techniques, and rebar concrete/mortar cover thickness. This paper focused on the largely ignored aspect of these factors, some of which are inherent and nearly non-circumventable, and will continue to lead to suboptimal performance of any CTL predictive model when not addressed. Recommendations for standardizing practices are proposed to improve CTL assessment consistency, reliability of developed CTL predictive models, and accuracy of service life modeling.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04167"},"PeriodicalIF":6.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sustainable geopolymer adsorbents utilizing silica fume as a partial replacement for metakaolin in the removal of copper ion from synthesized copper solution","authors":"Pilomeena Arokiasamy ,&nbsp;Mohd Mustafa Al Bakri Abdullah ,&nbsp;Eva Arifi ,&nbsp;Noorina Hidayu Jamil ,&nbsp;Md Azree Othuman Mydin ,&nbsp;Shayfull Zamree Abd Rahim ,&nbsp;Andrei Victor Sandu ,&nbsp;Shafiq Ishak","doi":"10.1016/j.cscm.2024.e04142","DOIUrl":"10.1016/j.cscm.2024.e04142","url":null,"abstract":"<div><div>Biochar has great significance for controlling heavy metal pollution. Nevertheless, its application is impeded by certain shortcomings, such as a limited adsorption capacity, a slow adsorption rate, and poor reusability. Besides, the physical adsorption capacity of raw biochar to heavy metals is suboptimal. As a result, researchers prefer to use geopolymer-based adsorbents for the removal of heavy metals due to their excellent immobilization effect. However, no research has been done on the synthesis of geopolymer-based adsorbent using silica fume for heavy metal adsorption. Thus, the aim of this study is to partially replace metakaolin (MK) with silica fume (S1) (25, 50, 75 and 100 %) in geopolymer formulation at varied S:L ratio (0.4, 0.6, 0.8 and 1.0) to study the impact on the geopolymerization and its following properties in the removal efficiency of copper (Cu^2 +). Characterization techniques such as Energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM) and Energy dispersive X-ray spectroscopy (EDX) were used to study the physicochemical properties of the developed geopolymer. The concentration of Cu²⁺ before and after adsorption was determined by Atomic absorption spectroscopy (AAS) and the removal efficiency was calculated. Based on the experimental result, the geopolymer prepared with 25 % MK and 75 % S1 at S:L of 0.6 maintained the high removal efficiency of Cu²⁺ (99.62 %) with 100 % MK geopolymer (98.56 %). The generation of N-A-S-H gel with the 75 % replacement level of S1 producing more reactive Si and Al binding sites for Cu²⁺ adsorption. In addition, S1 contains exchangeable cations such as Ca²⁺, Mg²⁺ and Na⁺ which further promote the adsorption of Cu²⁺ by ion exchange. Moreover, the mechanisms such as chemical bonding and precipitation were involved in the adsorption of Cu²⁺. Hence, this research could serve as a basis for the development of solid waste based geopolymers that could remove heavy metal ions from aqueous solution.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04142"},"PeriodicalIF":6.5,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation of hollow-core FRP-concrete-steel column subjected to the combined collision and blast loads","authors":"Zailin Yang ,&nbsp;Yongtao Mi ,&nbsp;Weiqiang Wang ,&nbsp;Jian Zhao ,&nbsp;Yicun Chen","doi":"10.1016/j.cscm.2024.e04143","DOIUrl":"10.1016/j.cscm.2024.e04143","url":null,"abstract":"<div><div>Hollow-core fiber-reinforced polymer-concrete-steel (HC-FCS) column is emerging as a viable option as the bridge pier that has excellent structural performance and superior corrosion resistance. Although the HC-FCS column exhibits superb resilience under the separate collision or blast load, its behavior under the combined collision and blast (C-C-B) loads has not been studied. In this study, extensive numerical studies were performed to investigate the dynamic behavior of HC-FCS column against the C-C-B loads. Refined numerical models were established and their accuracies were validated against the existing test data. Afterwards, the dynamic responses of HC-FCS column against the separate collision, separate blast, as well as the C-C-B loads were studied. The damage patterns, the impact force (F) and deflection (D)-time histories, the bending moment (BM) and shear force (SF)-time histories were recorded and analyzed. The simulation results indicate that the HC-FCS column experiences more severe damage and larger residual deflection when subjected to the C-C-B loads, but it still exhibits in a highly ductile manner. Furthermore, the influences of main variables on the dynamic responses of HC-FCS column subjected to the C-C-B loads were investigated through parametric studies. Finally, the damage of HC-FCS column with different loading scenarios were quantitively evaluated and discussed.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04143"},"PeriodicalIF":6.5,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating subgrade dynamic and static resilience modulus through enhanced testing techniques","authors":"Naitian Zhang ,&nbsp;Peng Wang ,&nbsp;Chengdong Xia ,&nbsp;Lin Gao ,&nbsp;Yongze Wang ,&nbsp;Songtao Lv ,&nbsp;Wang Dikuan","doi":"10.1016/j.cscm.2024.e04159","DOIUrl":"10.1016/j.cscm.2024.e04159","url":null,"abstract":"<div><div>This study investigates the impact of pavement structure self-weight on the dynamic and static resilient modulus of subgrade materials and proposes a prediction model to account for this effect. Traditional methods for measuring subgrade modulus are limited in simulating repeated traffic loading and the influence of self-weight, leading to inaccurate evaluations. To address this, a novel test device capable of applying cyclic loads was developed. Dynamic and static modulus tests were conducted using different bearing plate and lantern ring sizes to simulate the self-weight effect. Results show that the resilient modulus decreases as the bearing plate size increases, stabilizing at 30 cm, while the modulus increases with the collar size, stabilizing at 50 cm for a 20 cm plate and 35 cm for a 30 cm plate. A prediction model for dynamic and static resilient modulus, incorporating the effect of pavement self-weight, was developed. This model enhances the accuracy of subgrade modulus predictions, contributing to more reliable pavement structure designs. The findings are significant for improving the efficiency and accuracy of subgrade testing, with important implications for pavement design and maintenance.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04159"},"PeriodicalIF":6.5,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The application of geopolymers in the renovation of the historical ceramic tiles in the pilgrimage church of St. John of Nepomuk (Czech Republic)","authors":"Ivana Perná ,&nbsp;Martina Novotná ,&nbsp;Tomáš Hanzlíček ,&nbsp;Jakub Rafl ,&nbsp;Martina Nováková","doi":"10.1016/j.cscm.2024.e04161","DOIUrl":"10.1016/j.cscm.2024.e04161","url":null,"abstract":"<div><div>This article describes the use of geopolymer materials for the renovation of historical ceramic tiles from the mosaic floor of the church of St. John of Nepomuk. The restoration project, carried out in close cooperation with expert restorers, proceeded in several stages. These stages included initial experiments to assess the suitability of the geopolymer material, the development and adjustment of the geopolymer composition, the possibility of coloring the mixture, and extensive testing to evaluate the effect of ambient temperature on the geopolymer setting. Experiments with different geopolymer mixtures have shown that higher slag content can reduce the setting time but it also changes the consistency, color and surface hardness of the material, which are crucial properties for restorers. Finally, suitable geopolymer mixtures were created to meet the specific requirements of restorers. The project involved the successful bonding and reinforcement of damaged tiles in a controlled laboratory environment. The restoration process was concluded with an <em>in-situ</em> application – filling in the missing parts of the ceramic tiles in the church. This comprehensive approach highlights the potential of tailored geopolymer materials in the protection of cultural heritage.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04161"},"PeriodicalIF":6.5,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic behavior and residual performance of CFDSTCs under coupled collision and blast loads","authors":"Yongtao Mi ,&nbsp;Huiqi Ren ,&nbsp;Chenxi Sun ,&nbsp;Jian Zhao ,&nbsp;Weiqiang Wang ,&nbsp;Zailin Yang ,&nbsp;Yicun Chen","doi":"10.1016/j.cscm.2024.e04147","DOIUrl":"10.1016/j.cscm.2024.e04147","url":null,"abstract":"<div><div>Bridges can suffer partial or even total collapse when bridge piers, as crucial load-bearing bridge components, are hit by vehicles or ships. Concrete-filled double-skin steel tubular columns (CFDSTCs) offer high bearing capacity and good fire resistance, exhibit excellent mechanical properties under separate collision or blast load, and have broad application prospects in bridge structures. However, in extreme cases, CFDSTCs can be subjected to coupled collision and blast (CCB) loads, initiating coupling effects. In this study, the dynamic behavior and residual performance of CFDSTCs under CCB loads were investigated. First, the reliability of the numerical model was validated on the basis of existing experimental results. Second, the damage propagation process of CFDSTCs subjected to the separate collision and CCB loads was investigated, and the patterns of damage, deflection (D), and impact force (F) time histories were comparatively analyzed. The performance level of CFDSTCs after the CCB loads was determined based on the damage index thresholds. Finally, the primary determinants affecting the dynamic behavior and residual performance of CFDSTCs were investigated. The results showed that compared with the sum of the deflections under the separate collision and blast loads, the maximum deflection and residual deflection under CCB loads increased by 6.1 mm and 7.8 mm, respectively.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04147"},"PeriodicalIF":6.5,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}