Case Studies in Construction Materials最新文献

{"title":"Investigation of fresh, shrinkage, and mechanical properties in iron sand high-strength engineered cementitious composites: Effects of water-to-binder ratio and fiber volume fraction","authors":"Zhi Zhang ,&nbsp;Nauman Ahmad ,&nbsp;Ajad Shrestha ,&nbsp;Ziming Tang ,&nbsp;Ziwei Cai ,&nbsp;Rustam Ergashev ,&nbsp;Iftikhor Kalandarbekov ,&nbsp;Lingfei Liu ,&nbsp;Lingzhi Li","doi":"10.1016/j.cscm.2024.e04138","DOIUrl":"10.1016/j.cscm.2024.e04138","url":null,"abstract":"<div><div>High-strength engineered cementitious composites (HS-ECC) provide remarkable advantages in the construction industry by reducing specimen size and improving material utilization, leveraging the benefits of engineered cementitious composites (ECC) and ultra-high-performance concrete (UHPC). However, challenges such as material scarcity, low elastic modulus, and high shrinkage limit the widespread application of HS-ECC. This research addresses these issues by developing HS-ECC through substituting quartz sand with iron sand under different water-to-binder (<em>w</em>/<em>b</em>) ratios to achieve high elastic modulus, low shrinkage, and varying compressive strength levels. Ten HS-ECC mixtures were produced with various <em>w</em>/<em>b</em> ratios, aggregate types, and fiber volume fractions to assess their impacts on fresh, shrinkage, and mechanical properties. The experimental results demonstrated that substituting quartz sand with iron sand decreased shrinkage. Specifically, iron sand HS-ECC showed a decrease in autogenous and drying shrinkage by 22.5 % and 23.6 %, respectively, compared to quartz sand HS-ECC at 0.14 <em>w</em>/<em>b</em> ratio. Additionally, as the <em>w</em>/<em>b</em> ratio increased from 0.14 to 0.20, autogenous and total shrinkage decreased by more than 14.0 %, while drying shrinkage increased by more than 74.7 %. For workability tests, slump flow and consistency increased with higher <em>w</em>/<em>b</em> ratios, albeit with a concurrent reduction in mechanical strength. Notably, the elastic modulus increased by 6.8 % at 0.16 <em>w</em>/<em>b</em> ratio with iron sand substitution. This study lays the groundwork for the developing HS-ECC with higher elastic modulus and lower shrinkage, contributing to advancement of this promising material in civil engineering applications.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04138"},"PeriodicalIF":6.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145823","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":"Mapping stains on flat roofs using semantic segmentation based on deep learning","authors":"Lara Monalisa Alves dos Santos ,&nbsp;Leonardo Rabero Lescano ,&nbsp;Gabriel Toshio Hirokawa Higa ,&nbsp;Vanda Alice Garcia Zanoni ,&nbsp;Lenildo Santos da Silva ,&nbsp;Cesar Ivan Alvarez ,&nbsp;Hemerson Pistori","doi":"10.1016/j.cscm.2024.e04106","DOIUrl":"10.1016/j.cscm.2024.e04106","url":null,"abstract":"<div><div>Moisture stains indicate ongoing degradation processes and may reveal areas of the roof slab where water infiltration occurs, compromising the performance and durability of the building system. During inspections of roofing systems, an inspector's field of vision differs from that of drones during overflights. As a result, traditional inspections might not always detect the presence and severity of stains, making maintenance on flat roofs a complex task. In this context, this experimental study aims to analyze deep learning-based semantic segmentation with images obtained from drones to map and monitor damp patches during automated building inspections of flat roof systems. The research tested two convolutional neural networks for semantic segmentation: the Fully Convolutional Network (FCN) with a ResNet50 backbone and DeepLabV3 with a ResNet101 backbone, as well as a transformer-based deep artificial neural network called SegFormer with a MiT-B1 backbone. We evaluated three optimizers for each model—Adam, Adagrad, and SGD—along with learning rates of 1e-2, 1e-3, and 1e-4. The models were compared using four performance metrics. The FCN, optimized with Adagrad at a learning rate of 1e-2, showed the best results. The average metrics obtained in this case were as follows: precision: 79.69 %, recall: 67.81 %, F-score: 73.09 %, and Intersection over Union (IoU): 57.70 %.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04106"},"PeriodicalIF":6.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147270","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":"Experimental study on the effect of nano SiO2 dispersion on the compressive strength and early high-temperature resistance of modified cement paste","authors":"Zhang Xiaowei,&nbsp;Pei Xiaofang,&nbsp;Zhao Sheng,&nbsp;Shi Haoran,&nbsp;Wu Linsong","doi":"10.1016/j.cscm.2024.e04135","DOIUrl":"10.1016/j.cscm.2024.e04135","url":null,"abstract":"<div><div>This study investigates the influence of varying levels nano-silica (NS) dispersion levels on cement paste (CP) properties. Utilizing ultrasonic dispersion and water-reducing agent, NS was uniformly dispersed within the CP. This research methodically investigates the dispersion of NS and its subsequent effects on CP's mechanical properties, high-temperature resistance and microstructure. The findings demonstrated that effectively dispersed NS markedly improved CP's initial and residual compressive strength after high-temperature exposure. Optimal comprehensive performance of the cement paste was achieved with an ultrasonic dispersion duration of 40 min, an NS concentration of 1.0 wt%, and Polycarboxylate Ether concentration of 0.75 wt%. The 28-day compressive strength was 83.7 MPa, and the normalized residual compressive strength was 37.3 % after holding at 800 ºC for 2 h. Microstructure analyses indicate that optimal NS dispersion facilitates the early cement hydration process by filling minute voids and increasing the compactness of the cement matrix. This enhancement positively impacts CP's internal structure, mitigating crack formation and growth, thus enhancing compressive strength and high-temperature resilience.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04135"},"PeriodicalIF":6.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146164","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":"Modeling and comparative analysis of sustainable cotton rope confinement: Full vs. STrip wrapping for enhanced concrete strength and ductility","authors":"Panumas Saingam ,&nbsp;Chaitanya Krishna Gadagamma ,&nbsp;Qudeer Hussain ,&nbsp;Hnin Hnin Hlaing ,&nbsp;Rawirot Suwannatrai ,&nbsp;Muhammad Irshad Qureshi ,&nbsp;Kaffayatullah Khan ,&nbsp;Ali Ejaz","doi":"10.1016/j.cscm.2024.e04134","DOIUrl":"10.1016/j.cscm.2024.e04134","url":null,"abstract":"<div><div>The rise of natural FRPs as ecological alternatives to synthetic ones has highlighted the need for studies on partial confinement using cotton ropes, which offer cost-effective, low-carbon solutions with high rupture strain. Unlike full confinement, partial confinement through cotton rope strips can efficiently strengthen deteriorated concrete sections with reduced material usage. Despite possessing several advantages, the partial confinement by cotton on concrete has not been investigated. This study addresses the gap by investigating the performance of cotton rope strips and developing analytical models to predict their structural impact. This study tested cylindrical concrete specimens of two strengths, strengthened with cotton rope in either complete wrapping (Group 1) or strip wrapping (Group 2). Each group was further divided by concrete strength and included one unstrengthened specimen, and three strengthened with one, two, or three layers of cotton rope. Experimental results revealed that cotton rope wraps effectively confined the concrete, enhancing load-bearing capacity and improving ultimate compressive strength by 9.97–152.10 % and ultimate strain by 188.00 % to 1488.89 %. The compressive stress vs. strain behavior exhibited an initial stiff elastic ascent followed by a parabolic transition. The second branch of the response, either ascending or descending, was significantly improved with an increased confinement ratio. Type-I failure was characterized by an ascending second branch in the compressive stress vs. strain curve, while Type-II failure exhibited a descending second branch. Four specimens demonstrated Type-I failure (L-2F, L-3F, H-3F, and L-3S), predominantly in full configurations and with lower unconfined compressive strength. The modulus of the second branch improved with an increased confinement ratio, transitioning from Type-II to Type-I failure near a ratio of approximately 0.50. Regression analysis provided equations of various key points along the compressive response with <em>R²</em> values greater than 0.90, highlighting a strong dependence on the confinement ratio. The Popovics model effectively predicted the first part of the compressive response, with predicted curves closely matching experimental results.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04134"},"PeriodicalIF":6.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146160","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":"Experimental investigation and theoretical analysis of long-term performance for optical fiber Bragg grating-fiber reinforced composite in alkaline concrete environment","authors":"Tiejun Liu ,&nbsp;Yangyu Fu ,&nbsp;Kexuan Li ,&nbsp;Ao Zhou ,&nbsp;Renyuan Qin ,&nbsp;Dujian Zou","doi":"10.1016/j.cscm.2024.e04130","DOIUrl":"10.1016/j.cscm.2024.e04130","url":null,"abstract":"<div><div>Fiber reinforced composite (FRP) is a promising material to encapsulate optical fiber Bragg grating sensors for in-situ structural monitoring and reinforcement. However, the long-term performance of multifunctional optical fiber Bragg grating-basalt fiber reinforced polymer (OFBG-BFRP) in concrete structures remains unclear. Hence, its mechanical and sensing properties under alkaline concrete condition were experimentally investigated and theoretically analyzed. The results showed that the tensile strength and strain sensing range of OFBG-BFRP decreased by 22 % and 43 % under alkaline concrete condition, respectively. The relationship between the elastic modulus and sensing sensitivity was significant with 0.77 Person correlation coefficient. It is revealed that, for OFBG-BFRP bar, the sensing performance degradation in alkaline concrete condition was mainly caused by optical fiber-resin interfacial debonding, while the mechanical deterioration was attributed to resin hydrolysis and basalt fiber-resin interfacial debonding. Based on the deterioration mechanism and chemical etching theory, a service life prediction model is proposed to evaluate the performance of OFBG-BFRP accurately. This work facilitates in-depth understanding on the deterioration behavior and mechanism of OFBG-BFRP bars in concrete structures, inspiring accurate service life prediction for safe and durable FRP reinforced concrete structures.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04130"},"PeriodicalIF":6.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145826","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":"Property enhancement and mechanism of cement-based composites from the perspective of nano-silica dispersion improvement","authors":"Tonghuan Zhang ,&nbsp;Zhenjun Wang ,&nbsp;Wei Wang ,&nbsp;Gang Li ,&nbsp;Haoyan Guo ,&nbsp;Haibao Zhang","doi":"10.1016/j.cscm.2024.e04125","DOIUrl":"10.1016/j.cscm.2024.e04125","url":null,"abstract":"<div><div>Nano-silica (NS) exhibits significant potential for enhancing the properties of cement materials. However, its effectiveness in improving the properties of cement-based materials is hindered by the poor dispersion of NS within the cement matrix. In this work, the dispersibility of NS in cement solutions was improved by water reducers (FDN-C naphthalene water reducer and PCE-11 polycarboxylate superplasticizer) and mechanical dispersion methods (ultrasonication and magnetic stirrer), and their synergistic effects were investigated by ultraviolet visible spectrophotometry and zeta potential tests. Effects and mechanism of NS dispersibility on microstructure and properties of NS modified cement pastes (NS-C) were also investigated and analyzed. Results indicate that polycarboxylate superplasticizers have stronger adsorption on the surface of NS particles compared with naphthalene water reducers, which effectively improved the dispersion stability of NS in cement solutions. Furthermore, ultrasonication can ensure better dispersion of NS than magnetic stirrer. The synergistic effects of 1.0 % polycarboxylate superplasticizers and 1 h of ultrasonication enhances the dispersion of NS aggregates, thereby promoting the hydration reaction of cement and refining the pore structure. Additionally, this synergistic effect improves the workability and the compressive strength of NS-C. Thermogravimetric (TG) and industrial computed tomography (ICT) results indicated that the increase in C-S-H gel and the reduction in the volume of large pores (greater than 10 mm³) in NS-C dispersed synergistically with 1 % polycarboxylate superplasticizers and 1 h of ultrasonication are the mainly reasons for the improvement in compressive strength.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04125"},"PeriodicalIF":6.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146145","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":"Experimental and numerical analysis of traditional wooden glass windows subject to extraordinary dynamic loads","authors":"Martin Ščotka,&nbsp;Zuzana Papánová","doi":"10.1016/j.cscm.2024.e04127","DOIUrl":"10.1016/j.cscm.2024.e04127","url":null,"abstract":"<div><div>Traditional wooden windows are still prominently present today among the glass parts of older, still-used buildings. Increasingly often, they must withstand extraordinary dynamic loads such as explosions, bird collisions or various natural disasters. From a mechanical standpoint, their resistance is a significant drawback, especially when under the dynamic impact loads to which they are subjected in these extreme situations. To increase the resistance of glass window infills, various safety features are currently in use. One of them is polyethylene terephthalate-based safety foil (PET). However, its effect on the load-bearing capacity of glass is questionable. In terms of the background of the research, it can be stated that a number of research teams around the world have addressed the partial issues of window system resistance in depth. A more comprehensive connection of individual analyses and a focus on “traditional wooden windows” in relation to explosion, impact and additional foil reinforcement has not yet been performed. The aim of this paper is to compare the resistance of the glass infills of traditional wooden windows subjected to extraordinary dynamic load in both cases – before and after their reinforcement with safety foil. In the experimental phase, both tested samples are subjected to hardbody impact and explosion. An essential part of research in multiple branches of dynamics is currently the linking of experimental and numerical methods. The methodology used to achieve the research objective consists of two fundamental approaches: an in-lab experiment correlated with analytical tools in order to tune the inputs for the Finite Element Method (FEM) model, and an in-situ experiment compared with the tuned FEM model to derive conclusions for practice and further research. The paper provides a verification of the experimentally obtained parameters by numerical modeling based on the finite element method in the ANSYS Workbench system interface. One of the main results of the research presented in this paper was a tuned computational model of a traditional wooden window in terms of its behavior towards explosion and hard body impact, which clearly identifies the problems and challenges of modelling its individual structural parts. One of the main conclusions of the paper is the minimal effectiveness of the PET foil for the static load-bearing capacity of the traditional wooden window, its slightly increased damping in dynamic response to extreme impact loads and its high effectiveness in protecting against shattering glass fragments at the collapse of the glass infill. These conclusions are supported by detailed analyses of a series of 7 pendulum test measurements under laboratory conditions, 6 explosion measurements of two different explosives, and the identification of 6 natural modes and natural frequencies of vibration.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04127"},"PeriodicalIF":6.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146619","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":"An enhanced approach to red mud (RM) sustainable management and utilization for marl stabilization considering the dynamic response and durability analysis","authors":"Amir Hossein Vakili ,&nbsp;Mahdi Salimi ,&nbsp;İnan Keskin ,&nbsp;Mehmet İnanç Onur ,&nbsp;Abdollah Tabaroei ,&nbsp;Mohammadhossein Dadgar","doi":"10.1016/j.cscm.2024.e04084","DOIUrl":"10.1016/j.cscm.2024.e04084","url":null,"abstract":"<div><div>Marl soil, known for its high calcite content, presents significant challenges in construction projects due to its low strength and poor durability, especially under varying moisture conditions. In wet environments, marl often exhibits rapid disintegration, compromising stability and limiting its use in geotechnical applications. On the other hand, the worldwide disposal of red mud (RM) waste, an industrial by-product of alumina processing, has resulted in significant environmental concerns and substantial financial burdens. This study investigates the potential of RM for enhancing the mechanical, dynamic, and durability characteristics of marl soil under both dry and wet conditions. The experiments included the unconfined compressive strength test (UCS), Brazilian tensile strength test (BTS), bender element test (BET), long-time soaking test, as well as a set of microstructural analyses. The findings indicated that the UCS of the samples containing 30 % RM increased by 3.6 and 6.83 times after curing periods of 7 and 28, respectively, reaching an acceptable strength level even under wet conditions. Furthermore, RM was found capable of postponing the development of cracks and sustaining the integrity of the sample over the long term. RM treatment also improved the dynamic properties, increasing shear wave velocity by 127.9 % and reclassifying the soil from Class F (very weak) to Class D (very stiff) under seismic loading criteria. However, RM introduced brittle behavior to the treated samples, resulting in reduced axial strain and a 60–70 % drop in strength under wet conditions. Future research should focus on addressing these limitations by incorporating additional stabilizing agents. This study highlights the potential of RM for sustainable soil stabilization, offering an effective approach to managing industrial waste while enhancing marl’s performance in geotechnical applications.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04084"},"PeriodicalIF":6.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145825","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":"Investigating the microscopic, mechanical, and thermal properties of vacuum-sintered BH-1 lunar regolith simulant for lunar in-situ construction","authors":"Yu Jiang ,&nbsp;Feng Li ,&nbsp;Siqi Zhou ,&nbsp;Li Liu","doi":"10.1016/j.cscm.2024.e04132","DOIUrl":"10.1016/j.cscm.2024.e04132","url":null,"abstract":"<div><div>The lunar base establishing is crucial for the long-term deep space exploration. Given the high costs associated with Earth-Moon transportation, in-situ resource utilization (ISRU) has become the most viable approach for lunar construction. This study investigates the sintering behavior of BH-1 lunar regolith simulant (LRS) in a vacuum environment across various temperatures. The sintered samples were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM), along with nanoindentation, uniaxial compression, and thermal property tests to evaluate the microstructural, mechanical, and thermal properties. The results show that the sintering temperature significantly affects both the microstructure and mechanical strength of the samples. At a sintering temperature of 1100°C, the compressive strength reached a maximum of 90 MPa. The mineral composition of the sintered samples remains largely unchanged at different sintering temperatures, with the primary differences observed in the XRD peak intensities of the phases. The plagioclase melting first and filling the intergranular pores as a molten liquid phase. The BH-1 LRS exhibited a low coefficient of thermal expansion (CTE) within the temperature range of −150°C to 150°C, indicating its potential for resisting fatigue damage caused by temperature fluctuations. These findings provide technical support for the in-situ consolidation of lunar regolith and the construction of lunar bases using local resources.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04132"},"PeriodicalIF":6.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145819","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":"Alkali-activated pastes by Basic Oxygen Furnace slag and fly ash: Mechanical and microstructural analysis","authors":"Heloina Nogueira da Costa ,&nbsp;Antônio Eduardo Bezerra Cabral ,&nbsp;Ricardo Emílio Ferreira Quevedo Nogueira","doi":"10.1016/j.cscm.2024.e04128","DOIUrl":"10.1016/j.cscm.2024.e04128","url":null,"abstract":"<div><div>This study aims to investigate the mechanical behavior and microstructure formation of alkali-activated pastes prepared from basic oxygen furnace (BOF) steel slag and fly ash (FA). In addition, the fluidity and setting time of five different proportions of FA and BOF (0/100, 75/25, 50/50, 25/75 and 100/0) were prepared using silicate and sodium hydroxide as activators. Compressive strength (1, 7 and 28 days), stress-strain curve, modulus of elasticity and fracture energy were evaluated in the hardened state. Infrared spectroscopy, scanning electron microscopy, X-ray diffraction and thermal analysis were used to analyze the microstructure. The best mini-slump results was 50/50 paste with 117.3 mm, 8.0 Pa and 2096.8 kg/m³ of spreading diameter, yield stress and density, respectively. The calcium present in BOF accelerated the setting time. Compressive strength of paste 50/50 presented higher, 52.3, 57.6 and 62.3 MPa at 1, 7 and 28 days and also the higher modulus of elasticity (25.9 GPa) and fracture energy (116.9 N/m). Microstructural analyses indicate the increasing the BOF slag content, increases the availability of calcium, densifying the microstructure, due to the formation of C-(N)-A-S-H (hydrated calcium aluminosilicate) and C-A-S-H (hydrated calcium aluminosilicate) gels, which are also responsible for the mechanical strength growth up to 50 % BOF increment. However, in pastes with higher fly ash contents (75/25 and 100/0), the N-A-S-H (hydrated sodium aluminosilicate) gel type predominates. Therefore, the results obtained confirm the potential of using BOF slag as a calcium and Fa as a silica source in alkali-activated pastes.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04128"},"PeriodicalIF":6.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145885","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}