Case Studies in Construction Materials最新文献

{"title":"Comparative study of mechanical properties of one-part alkali-activated slag concrete using deformed and recycled tire steel fibers","authors":"Ali Abdulkarim,&nbsp;Hossein Tajmir Riahi,&nbsp;Abdolreza Ataei","doi":"10.1016/j.cscm.2024.e04124","DOIUrl":"10.1016/j.cscm.2024.e04124","url":null,"abstract":"<div><div>The significance of finding industrial waste solutions in the construction industry plays a crucial role in the quest for environmental conservation. To reduce the carbon footprint, this research has focused on developing solutions. This study assesses the mechanical properties of water-cured alkali-activated slag concrete (AASC) prepared using a one-part activator, where the dry alkali activator is pre-mixed with slag before water addition. The mix is then reinforced with three types of steel fibers, namely deformed steel fibers (DSF), recycled tire steel fiber (RTSF), and hybrid steel fiber (HSF) at varying volume fractions (0.5 %, 0.75 %, and 1.0 %). Numerous characteristics, including workability, compressive strength, flexural strength, splitting tensile strength, flexural toughness, and SEM observations in short-term, and stress-strain response under uniaxial compression, modulus of elasticity, peak strain and energy absorption in long-term were assessed. According to the test results, compressive strength was largely unaffected by fiber addition, with DSF at 1 % volume (DSF1) achieving the highest strength (58.51 MPa at 28 days). Conversely, optimal compressive strength for RTSF was observed at 0.5 % volume. On the other hand, the concrete mixes' splitting tensile, and flexural strengths increased with the addition of steel fibers achieving maximum values at 1 % DSF. The addition of steel fibers transformed the stress-strain response of one-part AASC mixes from brittle to ductile, with HSF specimens at 1 % volume (HSF1) exhibiting a 50 % increase in strain related to peak stress compared to the reference. Remarkably the HSF1 mix achieved a 421 % increase in toughness at 365 days compared to the reference mix. The DSF1 mix at 28 days and HSF1 at 365 days achieved the highest energy absorption capacity. Overall, the inclusion of 1 % DSF, RTSF, and HSF fibers enhanced the mechanical properties of one-part AASC, with DSF providing the most significant improvements at 28 days.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04124"},"PeriodicalIF":6.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146622","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":"Hydration and rheological properties of municipal sludge co-processing cement","authors":"Jianyun Wang ,&nbsp;Xianglong Ji ,&nbsp;Depeng Chen ,&nbsp;Chunxiang Qian ,&nbsp;Gang Liu","doi":"10.1016/j.cscm.2024.e04126","DOIUrl":"10.1016/j.cscm.2024.e04126","url":null,"abstract":"<div><div>The recycling and co-processing of municipal sludge in the production of cement clinker is a promising technology for the valorization of municipal solid wastes. However, the Al and Si rich in municipal sludge and the presence of heavy metals usually results in the different performance of municipal sludge co-processed cement (CPC) from normal ordinary Portland cement (OPC). To understand the variation in fresh behaviour, this study evaluated the flowability and rheological properties of CPC and OPC pastes with dosages of superplasticizers (SP). The hydration kinetics and hydration products of pastes in the fresh state were characterized. The influences of SP on the hardening properties of CPC and OPC samples were further addressed. The result indicated that the incorporation of SP provided a superior flowability of CPC pastes compared to OPC after mixing, however, the fast decline in flowability of CPC pastes in the first 40–80 minutes was confirmed. Consequently, CPC pastes presented faster development of static yield stress and dynamic yield stress compared to OPC with the SP dosage from 0.05 % to 0.125 %. CPC consumed significantly higher SP to achieve similar workability to OPC pastes. The characterization of reaction products indicated that hydration of CPC produced more ettringite and less portlandite in the first few minutes compared to OPC with or without SP. The application in OPC and CPC all reduced the volume of pores larger than 100 nm. The optimal SP could effectively promote the strength development of CPC and OPC at early ages.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04126"},"PeriodicalIF":6.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145822","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 shear strength and creep properties of loess modified by microbially induced calcium carbonate precipitation (MICP) under freeze-thaw cycles","authors":"Jiaming Liu ,&nbsp;Zhanyuan Zhu ,&nbsp;Junlin He ,&nbsp;Fei Luo ,&nbsp;Yuping Yang ,&nbsp;Huawei Gu ,&nbsp;Zhuoying Wang","doi":"10.1016/j.cscm.2024.e04119","DOIUrl":"10.1016/j.cscm.2024.e04119","url":null,"abstract":"<div><div>Numerous loess relic sites with cultural and historical values exist in the seasonally frozen ground region of Northwest China. Freeze-thaw action is an essential factor in inducing cracking and collapse of loess relic sites, and the creep behavior of loess also affects its long-term stability. Microbially induced calcium carbonate precipitation (MICP) technology has a promising application in earthen ruin reinforcement due to its environmental friendliness and good compatibility. To evaluate the feasibility of MICP technology for reinforcing loess relic sites in the seasonally frozen ground, triaxial compression tests, triaxial creep tests, and SEM tests were conducted on MICP modified loess after 0, 1, 3, 7, and 9 freeze-thaw cycles. Then, the changing laws of shear strength and creep properties of samples in the freeze-thaw conditions were analyzed. The results show that the MICP technology can enhance the mechanical properties and frost resistance of loess. The shear strength, cohesion, and long-term strength of MICP modified loess are enhanced by 27.8 %, 109 %, and 29.8 %, respectively, under 100 kPa confining pressure, and their reduction is smaller than that of the untreated loess after 9 freeze-thaw cycles; the internal friction angle fluctuates within 1°. Finally, the reinforcement mechanism and freeze-thaw resistance mechanism of MICP technology were revealed. Microbially induced calcium carbonate can cement soil particles, fill interparticle pores, and inhibit the development of pores and cracks caused by freeze-thaw action. The results can provide a theoretical foundation and scientific basis for the long-term stability analysis of loess relic sites reinforced with MICP technology.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04119"},"PeriodicalIF":6.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147257","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":"Analytical model of flexural performance for GFRP-reinforced concrete beams with constitutive model developed for new compression yielding (CY) block","authors":"Yongxiang Cui,&nbsp;Jiafei Jiang,&nbsp;Weichen Xue","doi":"10.1016/j.cscm.2024.e04122","DOIUrl":"10.1016/j.cscm.2024.e04122","url":null,"abstract":"<div><div>The compression yielding (CY) concept has proven to be an effective method for improving the insufficient flexural ductility of fiber-reinforced polymer reinforced concrete (FRP-RC) beams caused by the linear stress-strain characteristics of FRP bars. However, traditional CY materials exhibit limited variability in mechanical properties, particularly in terms of compressive strength, and they face durability issues. To address these challenges, this study introduces a novel CY block, developed by the authors, using PET FRP-confined engineered cementitious composite (ECC) with compression ductility as high as 25.81, meeting the requirement of CY blocks for compression ductility of no less than 20. This material makes it a suitable candidate for enhancing the performance of FRP-RC beams. Based on this, a design-oriented stress-strain model for the PET FRP-confined ECC was developed, followed by a validated analytical model of the flexural behavior of GFRP-RC beams with this CY block (briefly named as CY beam). The results indicate that the balanced reinforcement ratio for the CY beam is directly proportional to the height of the CY block, and the ultimate moment and curvature of the CY beam are enhanced by up to 56 % and 210 %, respectively, compared to conventional FRP-RC beams. Moreover, the deflection ductility of CY beams reaches 3–4 through reasonable design.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04122"},"PeriodicalIF":6.5,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145821","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 resistance to severe environmental erosion of modified Pisha sandstone composite materials","authors":"Changming Li ,&nbsp;Yaozong Wang ,&nbsp;Shunbo Zhao ,&nbsp;Biao Jia ,&nbsp;Yongsheng Tong ,&nbsp;Ruijuan Li ,&nbsp;Yanxin Gong","doi":"10.1016/j.cscm.2024.e04123","DOIUrl":"10.1016/j.cscm.2024.e04123","url":null,"abstract":"<div><div>Pisha sandstone (PS) was the main resource of the Yellow River coarse sediment. This study aimed to investigate the microstructural evolution and the erosion resistance of modified Pisha sandstone composite materials (PCM) in severe environmental erosion, including water, alkali, acid, and sulfate solutions. The mechanical properties of the PCM were assessed using a universal testing machine, while the erosion resistance of the PCM in different environments was compared through the softening coefficient and strength loss rate. Additionally, the study examined the enhancement effects of blast furnace slag and cement admixture on the erosion resistance of the material. Mineralogical composition and microstructure were analyzed using XRD, SEM and TG. The results indicated that the mechanical properties and the erosion resistance of the PCM increased significantly with the addition of blast furnace slag, with the softening coefficient of 0.78 and a strength of 16.3 MPa. After exposure to erosion, the compressive strength of the PCM can reach up to 16.6 MPa, 18.1 MPa, and 17.1 MPa in acidic, alkaline, and sulfate environments, respectively. Further analysis revealed that the types of montmorillonite minerals in the PS has been altered by modification treatment, subsequently the erosion resistance of the PCM has been enhanced. PCM exhibits distinct reaction mechanisms in different environments. The recrystallization of feldspar and calcite enhances structural integrity in water and alkaline environments. The montmorillonite and gel of PCM are subjected to further erosion in the acid environment, which leads to the formation of microcracks. The microscopic morphology of PCM appears layered and convex in sulfate environments.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04123"},"PeriodicalIF":6.5,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146141","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":"A study of blast furnace slag on the mechanical properties improvement and microstructure of hemihydrate phosphogypsum pretreated by calcium hydroxide","authors":"Liya Zhao ,&nbsp;Chunwei Wang ,&nbsp;Seunghyun Na ,&nbsp;Yuzhong Jin ,&nbsp;Wenjing Kang ,&nbsp;Jianping Zhu ,&nbsp;Wenyan Zhang ,&nbsp;Yadong Bian ,&nbsp;Surendra P. Shah","doi":"10.1016/j.cscm.2024.e04121","DOIUrl":"10.1016/j.cscm.2024.e04121","url":null,"abstract":"<div><div>Phosphogypsum (PG) pretreatment with calcium hydroxide (CH) effectively reduces environmental pollution but inversely decreases the mechanical strength of the hardened paste, which leads to its relatively low utilization rate in construction industry. Therefore, in order to enhance the properties of PG pretreated with CH, this study mainly investigate the addition of blast furnace slag (BFS) on the proeperties and microstructure of pretreated hemihydrate phosphogypsum by calcium hydroxide. The results indicated that the incorporation of BFS not only prolonged the setting time of PG, but also significantly enhanced mechanical properties and water resistance. The mechanical strength of samples with 40 % BFS was increased to 15.7 MPa at 28 days, which was 2.7 times compared with the reference sample. The analysis of phase composition change showed that the incorporation of BFS promoted the formation of new phases, such as ettringite (AFt) and calcium alumino silicate hydrate (C-A-S-H) gel, significantly altering the microstructure by affecting the relative content of hydration products. In addition, the incorporation of BFS could alter the crystallization behavior and morphology of gypsum, mainly caused by the dissolution rate of HPG particles and the nucleation and growth of gypsum due to the hydration environment change. Meanwhile, C-A-S-H gel encapsulated AFt and gypsum, imparting a dense microstructure characteristic. This study provides a theoretical foundation for optimizing PG and advances solid waste utilization on the development of sustainable building materials.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04121"},"PeriodicalIF":6.5,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147263","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":"Fatigue tests and assessment of high-yield-strength cold-rolled large-diameter ribbed steel bars","authors":"Jin-dou Liu ,&nbsp;Chuang Cui ,&nbsp;Song Xia ,&nbsp;Yan-qing Fu ,&nbsp;Hai-lin Chang","doi":"10.1016/j.cscm.2024.e04088","DOIUrl":"10.1016/j.cscm.2024.e04088","url":null,"abstract":"<div><div>Cold-rolled large-diameter ribbed steel bars have higher strength than hot-rolled steel bars but are susceptible to cracks, particularly at the root of the ribs, owing to the manufacturing process. This study investigated steel bars of 75 mm diameter produced using different manufacturing processes. Extensive testing of the specimens was conducted, including high-cycle fatigue tests under various high loadings, fatigue crack growth (FCG) rate at a stress ratio of 0.85, fracture surface analysis, and statistical analysis of the probabilities and FCG mechanisms. A fatigue life model considering the initial cracks in a ribbed steel bar was proposed based on the Paris and Walker models. Fewer rolling cycles and higher tempering temperatures accelerated the growth rate of the initial cracks. Finally, the FCG life was calculated using the integral equation under diverse processes and loading conditions. The critical thresholds for the initial crack length demonstrated the ability to withstand 2 × 10⁶ cycles under a stress amplitude of 88 MPa without fracture.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04088"},"PeriodicalIF":6.5,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143145818","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":"Application and feasibility analysis of knowledge-based machine learning in predicting fatigue performance of stainless steel","authors":"Jia Wang,&nbsp;Dongkui Fan,&nbsp;C.S. Cai","doi":"10.1016/j.cscm.2024.e04090","DOIUrl":"10.1016/j.cscm.2024.e04090","url":null,"abstract":"<div><div>To better predict the fatigue-related S-N curves of different series of stainless steels, 570 sets of data including fatigue test results and other performance parameters for five common types of stainless steel materials were initially collected. Eight machine learning models were deployed and analyzed using the dataset, and their predictive performances were evaluated using assessment metrics. Based on the best-performing model, corresponding S-N curves were constructed. The SHapley Additive exPlanations (SHAP) method was then applied to the optimal model to comprehensively describe and analyze the influence mechanisms of various factors on the number of cycles than stainless steel could withstand. Finally, the results predicted by the optimal model were compared with multiple design standards to verify the feasibility and effectiveness of the model in predicting the S-N curves of stainless steel materials. The results show that a genetic algorithm–optimized artificial neural network (GA-ANN) model possesses higher prediction accuracy than other models, with a correlation coefficient <span><math><msup><mrow><mi>R</mi></mrow><mn>2</mn></msup></math></span> of 0.98 and prediction data within a twofold error margin. The feature parameter constructed through feature engineering has the most significant impact on the number of cycles. The fatigue-related S-N curves predicted by the machine learning model can satisfy the requirements of design standards, demonstrating the feasibility of using this model to predict the fatigue property of stainless steel materials.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04090"},"PeriodicalIF":6.5,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146148","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":"Recycled cross-laminated timber as a low environmental impact alternative to virgin material: Latvia case study","authors":"Peteris Vasuks ,&nbsp;Ilze Vamza ,&nbsp;Megija Valtere ,&nbsp;Tereza Bezrucko ,&nbsp;Dagnija Blumberga","doi":"10.1016/j.cscm.2024.e04094","DOIUrl":"10.1016/j.cscm.2024.e04094","url":null,"abstract":"<div><div>Building with wood has become more popular and so has the circularity concept and carbon storage in products. This study aims to analyse the life cycle impacts of cross-laminated timber (CLT) recycling. Functional unit of 1 m³ was chosen for the CLT and recycled cross-laminated timber (ReCLT) comparison. For the life cycle assessment, the ReCiPe methodology was used allowing to calculate midpoint and endpoint accumulated impacts of both ReCLT and CLT, therefore allowing for the best comparison. Overall, the ReCLT showed significantly reduced environmental impacts in endpoint categories from 50 % to 80 % reduction in the single score evaluation. Although midpoint impacts showed mostly reduced environmental impacts, e.g., global warming, land use and others, the water eutrophication – both marine and freshwater, leading to think for improvements in the recycling process.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04094"},"PeriodicalIF":6.5,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147265","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":"Seismic fragility analysis of coastal bridges considering different corrosion damage modes among multiple RC bridge columns","authors":"Zhong-Kui Cai ,&nbsp;Wei Yuan ,&nbsp;Suchao Li ,&nbsp;Xiaolan Pan ,&nbsp;Zhi Zheng","doi":"10.1016/j.cscm.2024.e04099","DOIUrl":"10.1016/j.cscm.2024.e04099","url":null,"abstract":"<div><div>In a typical coastal bridge structure, the multiple reinforced concrete (RC) bridge columns possess different distributions of the atmospheric, splash-tidal, and submerged zone along the elevation, owing to the seabed topography and depth difference. Thereby, the corrosion damages are different among the multiple bridge columns. This phenomenon affects the bridge seismic fragility but has seldom been studied. Two main novelty of this study on the bridge seismic fragility are as follows. First, the variable corrosion deterioration rate along the height of one bridge column is considered. Second, the differences of the corrosion damages among multiple bridge columns are considered. Three sequential parts of research were conducted in this paper to bridge the research gap. (1) The bridge columns in one bridge were categorized into three types according to the corrosion damage characteristics. For each type of column, the life-cycle possible seismic failure modes were analyzed. (2) The corrosion processes of the coastal bridge columns in the three types were divided into two stages. The initial corrosion time and the time-dependent mechanical properties of the reinforcement were studied. (3) The seismic fragility of coastal bridges incorporating multiple bridge columns with different corrosion damages was analyzed by a case study. Research results indicate that for the multiple bridge columns in one coastal bridge, the time-dependent seismic failure modes are different due to different corrosion positions. Such differences should be considered when estimating the bridge’s seismic fragility in the service life. This paper provides the method to this complicated problem and also a case study to illustrate the method.</div></div>","PeriodicalId":9641,"journal":{"name":"Case Studies in Construction Materials","volume":"22 ","pages":"Article e04099"},"PeriodicalIF":6.5,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147262","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}