Pub Date : 2024-11-08DOI: 10.1016/j.dibe.2024.100571
Zhou Zhang, Chaolin Wang, Yu Zhao, Kun Zhang, Mingxuan Shen
This study aims to investigate the influence of corn cob particles on pore structure of mortar. By using NMR technology, the pore parameters of fast-hardening sulfoaluminate cement mortar (SAC) and ordinary Portland cement mortar (PO) were measured and compared. The influence of corncob particles on the mechanical properties of eco-mortar was evaluated by uniaxial compression test. The results indicate that medium and large pores of both SAC and PO increases with corn cob particle, as well as the porosity. The fractal dimensions of harmful and multiple harmful pores are negatively correlated with the volume fraction of corn cob particles. The addition of corn cob particles reduced the overall fractal dimension of the mortar and decreased the complexity of internal pores. The probability density function of grayscale values transitions from being “thin and tall” to “short and wide”, with an increasing proportion of high grayscale values. This leads to an increase in the proportion of large pores within the mortar, resulting in a continuous deterioration of pore structure. The addition of corn cob particles greatly reduces the strength of SAC and PO, but the peak stress of SAC is higher than that of PO. When corn cob particle content is 30 wt% and 50 wt%, the peak stress of SAC is increased by 23.37% and 14.25%, respectively, compared with the peak stress of PO.
本研究旨在探讨玉米芯颗粒对砂浆孔隙结构的影响。利用核磁共振技术，测量并比较了快速硬化硫铝酸盐水泥砂浆（SAC）和普通硅酸盐水泥砂浆（PO）的孔隙参数。通过单轴压缩试验评估了玉米芯颗粒对生态砂浆机械性能的影响。结果表明，随着玉米芯颗粒的增加，SAC 和 PO 的中孔和大孔以及孔隙率也随之增加。有害孔隙和多重有害孔隙的分形尺寸与玉米芯颗粒的体积分数呈负相关。玉米芯颗粒的加入降低了砂浆的整体分形维度，并减少了内部孔隙的复杂性。灰度值的概率密度函数从 "又细又高 "过渡到 "又短又宽"，灰度值高的比例越来越大。这导致砂浆内部大孔隙比例增加，导致孔隙结构不断恶化。玉米芯颗粒的加入大大降低了 SAC 和 PO 的强度，但 SAC 的峰值应力高于 PO。当玉米芯颗粒含量为 30 wt% 和 50 wt% 时，SAC 的峰值应力比 PO 的峰值应力分别增加了 23.37% 和 14.25%。
{"title":"Study on the pore structure of eco-regenerated mortar using corn cob based on nuclear magnetic resonance","authors":"Zhou Zhang, Chaolin Wang, Yu Zhao, Kun Zhang, Mingxuan Shen","doi":"10.1016/j.dibe.2024.100571","DOIUrl":"10.1016/j.dibe.2024.100571","url":null,"abstract":"<div><div>This study aims to investigate the influence of corn cob particles on pore structure of mortar. By using NMR technology, the pore parameters of fast-hardening sulfoaluminate cement mortar (SAC) and ordinary Portland cement mortar (PO) were measured and compared. The influence of corncob particles on the mechanical properties of eco-mortar was evaluated by uniaxial compression test. The results indicate that medium and large pores of both SAC and PO increases with corn cob particle, as well as the porosity. The fractal dimensions of harmful and multiple harmful pores are negatively correlated with the volume fraction of corn cob particles. The addition of corn cob particles reduced the overall fractal dimension of the mortar and decreased the complexity of internal pores. The probability density function of grayscale values transitions from being “thin and tall” to “short and wide”, with an increasing proportion of high grayscale values. This leads to an increase in the proportion of large pores within the mortar, resulting in a continuous deterioration of pore structure. The addition of corn cob particles greatly reduces the strength of SAC and PO, but the peak stress of SAC is higher than that of PO. When corn cob particle content is 30 wt% and 50 wt%, the peak stress of SAC is increased by 23.37% and 14.25%, respectively, compared with the peak stress of PO.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"20 ","pages":"Article 100571"},"PeriodicalIF":6.2,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654254","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}
Pub Date : 2024-11-05DOI: 10.1016/j.dibe.2024.100567
Changyuan Liu , Xin Wang , Xinquan Chang , Zhishen Wu , Huang Huang , Mohammad Noori , Wael A. Altabey
Owing to the low measuring range of traditional fiber Bragg grating (FBG) sensors and the complexity, imprecision, and lack of practicality in existing large-strain sensors, this paper introduces a novel type of large-strain sensor based on pre-relaxation and continuous sensing technology. This design aims to realize the whole-process strain monitoring of prestressed fiber reinforced polymer (FRP) plates. Static tensile tests were conducted on 9 large-strain sensor specimens. The effects of pre-relaxation degree, section number, pre-tension time, and prestressing level were evaluated. The results reveal that, the pre-relaxed sensor, proved its efficacy in capturing the strain pertinent to the post-tensioned operational state of the FRP plate, and a sensing performance of up to 18,923 με can be facilitated and further extended by a pre-relaxation and continuous sensing technique. Moreover, it is recommended that during the fabrication of the large-strain sensor, two pre-tensions be applied, with a prestressing level between 115% and 125% of the pre-relaxation degree.
由于传统的光纤布拉格光栅（FBG）传感器测量范围小，且现有的大应变传感器复杂、不精确、缺乏实用性，本文介绍了一种基于预松弛和连续传感技术的新型大应变传感器。该设计旨在实现对预应力纤维增强聚合物（FRP）板材的全过程应变监测。对 9 个大应变传感器试样进行了静态拉伸试验。评估了预松弛度、截面数、预拉伸时间和预应力水平的影响。结果表明，预松弛传感器在捕捉玻璃钢板后张力工作状态的相关应变方面证明了其有效性，而且通过预松弛和连续传感技术，可以促进并进一步扩展高达 18,923 με 的传感性能。此外，建议在制造大应变传感器时施加两个预张力，预应力水平介于预松弛度的 115% 和 125% 之间。
{"title":"Innovative design and sensing performance of a novel large-strain sensor for prestressed FRP plates","authors":"Changyuan Liu , Xin Wang , Xinquan Chang , Zhishen Wu , Huang Huang , Mohammad Noori , Wael A. Altabey","doi":"10.1016/j.dibe.2024.100567","DOIUrl":"10.1016/j.dibe.2024.100567","url":null,"abstract":"<div><div>Owing to the low measuring range of traditional fiber Bragg grating (FBG) sensors and the complexity, imprecision, and lack of practicality in existing large-strain sensors, this paper introduces a novel type of large-strain sensor based on pre-relaxation and continuous sensing technology. This design aims to realize the whole-process strain monitoring of prestressed fiber reinforced polymer (FRP) plates. Static tensile tests were conducted on 9 large-strain sensor specimens. The effects of pre-relaxation degree, section number, pre-tension time, and prestressing level were evaluated. The results reveal that, the pre-relaxed sensor, proved its efficacy in capturing the strain pertinent to the post-tensioned operational state of the FRP plate, and a sensing performance of up to 18,923 με can be facilitated and further extended by a pre-relaxation and continuous sensing technique. Moreover, it is recommended that during the fabrication of the large-strain sensor, two pre-tensions be applied, with a prestressing level between 115% and 125% of the pre-relaxation degree.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"20 ","pages":"Article 100567"},"PeriodicalIF":6.2,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654253","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}
Pub Date : 2024-11-02DOI: 10.1016/j.dibe.2024.100568
Yuxiang Tan , Bo Li , Yung-Tsang Chen , Yifeng Ling , Weizhuo Shi
The low water-to-binder ratio of ultra-high performance concrete (UHPC) often causes shrinkage and cracking due to early-age self-desiccation. This leads to significant initial dimensional instability, which may compromise structural integrity. As a promising solution, internal curing agents such as superabsorbent polymers (SAP) and natural zeolite have the potential to mitigate shrinkage and achieve self-stressing properties. This research aims to provide a comprehensive comparison between SAP and zeolite's effects within a consistent UHPC formulation. Six UHPC mixtures (including the reference mixture) were designed: three with SAP dosages of 0.2%, 0.4%, and 0.6% by cement mass, and two with zeolite replacing silica fume at 25% and 50% by mass. Various testing methods, including autogenous and drying shrinkage assessment, heat of hydration and thermogravimetric analysis, compressive strength evaluation, mercury intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), were employed to assess the mixtures at different stages of curing. The result reveals that the incorporation of SAP and zeolite in the mixtures significantly reduces UHPC's early-age autogenous shrinkage. Moreover, SAP and zeolite additions impact mechanical properties, demonstrating that a balance between shrinkage control and compressive strength can be reached, through an optimization of the additions to achieve the desired performance. Microstructural analysis through MIP and NMR reveals increased overall porosity of the UHPC with SAP and zeolite, suggesting that low-field NMR can be a valuable tool for complementing conventional test methods. The outcome of this study provided valuable insights into optimizing the balance between durability and mechanical performance, paving the way for more sustainable and cost-effective applications of UHPC in modern construction practices.
超高性能混凝土（UHPC）的水粘结比很低，常常会因早期龄期自干燥而导致收缩和开裂。这会导致初始尺寸严重不稳定，从而损害结构的完整性。作为一种有前途的解决方案，超吸收聚合物（SAP）和天然沸石等内部固化剂有可能缓解收缩并实现自应力特性。本研究旨在全面比较 SAP 和沸石在一致的 UHPC 配方中的效果。研究人员设计了六种 UHPC 混合物（包括参考混合物）：三种混合物的 SAP 用量分别为水泥质量的 0.2%、0.4% 和 0.6%，两种混合物的沸石取代硅灰的比例分别为 25% 和 50%。采用了各种测试方法，包括自生收缩和干燥收缩评估、水化热和热重分析、抗压强度评估、汞侵入孔隙比拟法（MIP）、核磁共振（NMR），以评估处于不同固化阶段的混合物。结果表明，在混合物中加入 SAP 和沸石可显著降低 UHPC 早期的自生收缩。此外，SAP 和沸石的添加对机械性能也有影响，这表明可以通过优化添加量来实现收缩控制和抗压强度之间的平衡，从而达到所需的性能。通过 MIP 和 NMR 进行的微观结构分析表明，添加了 SAP 和沸石的 UHPC 整体孔隙率增加，这表明低场 NMR 可以成为补充传统测试方法的重要工具。这项研究的成果为优化耐久性和机械性能之间的平衡提供了宝贵的见解，为在现代建筑实践中以更具可持续性和成本效益的方式应用 UHPC 铺平了道路。
{"title":"Effects of superabsorbent polymer and natural zeolite on shrinkage, mechanical properties, and porosity in ultra-high performance concretes","authors":"Yuxiang Tan , Bo Li , Yung-Tsang Chen , Yifeng Ling , Weizhuo Shi","doi":"10.1016/j.dibe.2024.100568","DOIUrl":"10.1016/j.dibe.2024.100568","url":null,"abstract":"<div><div>The low water-to-binder ratio of ultra-high performance concrete (UHPC) often causes shrinkage and cracking due to early-age self-desiccation. This leads to significant initial dimensional instability, which may compromise structural integrity. As a promising solution, internal curing agents such as superabsorbent polymers (SAP) and natural zeolite have the potential to mitigate shrinkage and achieve self-stressing properties. This research aims to provide a comprehensive comparison between SAP and zeolite's effects within a consistent UHPC formulation. Six UHPC mixtures (including the reference mixture) were designed: three with SAP dosages of 0.2%, 0.4%, and 0.6% by cement mass, and two with zeolite replacing silica fume at 25% and 50% by mass. Various testing methods, including autogenous and drying shrinkage assessment, heat of hydration and thermogravimetric analysis, compressive strength evaluation, mercury intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), were employed to assess the mixtures at different stages of curing. The result reveals that the incorporation of SAP and zeolite in the mixtures significantly reduces UHPC's early-age autogenous shrinkage. Moreover, SAP and zeolite additions impact mechanical properties, demonstrating that a balance between shrinkage control and compressive strength can be reached, through an optimization of the additions to achieve the desired performance. Microstructural analysis through MIP and NMR reveals increased overall porosity of the UHPC with SAP and zeolite, suggesting that low-field NMR can be a valuable tool for complementing conventional test methods. The outcome of this study provided valuable insights into optimizing the balance between durability and mechanical performance, paving the way for more sustainable and cost-effective applications of UHPC in modern construction practices.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"20 ","pages":"Article 100568"},"PeriodicalIF":6.2,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654204","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}
The deformation of long-span suspension bridges in multiple loads is an important indictor to reflect their operation state. However, the correlation between multiple loads and structural deformation is difficult to quantify. Therefore, this study proposes an explainable machine learning model for the load-deformation correlation in long-span suspension bridges using eXtreme Gradient Boosting (XGBoost) and SHapley Additive exPlanations (SHAP). Firstly, the structural health monitoring system for a suspension bridge was used to construct the dataset for the training and testing of XGBoost model. Herein, temperature, wind and vehicle loads were used as the input variables, while midspan deflections and expansion joint displacements were treated as outputs. Subsequently, the hyperparameters of XGBoost model were optimized using grid search and 5-fold cross-validation to ensure its prediction performance. Then, the prediction results were compared with other four machine learning methods (i.e., linear regression, artificial neural networks, gradient boosted decision trees and CatBoost). Finally, the correlation between different loads and displacement responses were explained by the SHAP method to identify the contribution of the loads on deformation. The results show that the XGBoost model has the highest prediction accuracy. Compared to vehicle and wind loads, temperature significantly affects the deformation of long-span suspension bridges during daily operation. The effects of temperature and wind on bridge deformation are independent, and there is no significant interaction between these two factors.
{"title":"Explainable machine learning model for load-deformation correlation in long-span suspension bridges using XGBoost-SHAP","authors":"Mingyang Chen , Jingzhou Xin , Qizhi Tang , Tianyu Hu , Yin Zhou , Jianting Zhou","doi":"10.1016/j.dibe.2024.100569","DOIUrl":"10.1016/j.dibe.2024.100569","url":null,"abstract":"<div><div>The deformation of long-span suspension bridges in multiple loads is an important indictor to reflect their operation state. However, the correlation between multiple loads and structural deformation is difficult to quantify. Therefore, this study proposes an explainable machine learning model for the load-deformation correlation in long-span suspension bridges using eXtreme Gradient Boosting (XGBoost) and SHapley Additive exPlanations (SHAP). Firstly, the structural health monitoring system for a suspension bridge was used to construct the dataset for the training and testing of XGBoost model. Herein, temperature, wind and vehicle loads were used as the input variables, while midspan deflections and expansion joint displacements were treated as outputs. Subsequently, the hyperparameters of XGBoost model were optimized using grid search and 5-fold cross-validation to ensure its prediction performance. Then, the prediction results were compared with other four machine learning methods (i.e., linear regression, artificial neural networks, gradient boosted decision trees and CatBoost). Finally, the correlation between different loads and displacement responses were explained by the SHAP method to identify the contribution of the loads on deformation. The results show that the XGBoost model has the highest prediction accuracy. Compared to vehicle and wind loads, temperature significantly affects the deformation of long-span suspension bridges during daily operation. The effects of temperature and wind on bridge deformation are independent, and there is no significant interaction between these two factors.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"20 ","pages":"Article 100569"},"PeriodicalIF":6.2,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654252","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}
Pub Date : 2024-10-29DOI: 10.1016/j.dibe.2024.100560
Simon Fischer , Harald Urban , Christian Schranz , Patrick Loibl , Léon van Berlo
This paper examines the potential for extending the Information Delivery Specification (IDS) schema to facilitate its integration into the building permit process. IDS is an open specification for defining and verifying information requirements for digital building models. Building authorities have already begun utilising IDS to define information requirements for automated code compliance checks. However, this requires the filtering of elements beyond the current scope of IDS. Such filtering functionality also has the potential to facilitate simple code compliance checks. This paper presents concepts for extending IDS to define information requirements for escape route analysis and code compliance checks for Austrian fire resistance regulations. The main extension was the filtering of elements depending on characteristics of related elements. Nesting existing functionalities enabled the schema to remain simple. A prototype implementation demonstrated that minor extensions to the IDS schema can significantly enhance its functionality, paving the way for broader applications of IDS.
{"title":"Extending Information Delivery Specifications for digital building permit requirements","authors":"Simon Fischer , Harald Urban , Christian Schranz , Patrick Loibl , Léon van Berlo","doi":"10.1016/j.dibe.2024.100560","DOIUrl":"10.1016/j.dibe.2024.100560","url":null,"abstract":"<div><div>This paper examines the potential for extending the Information Delivery Specification (IDS) schema to facilitate its integration into the building permit process. IDS is an open specification for defining and verifying information requirements for digital building models. Building authorities have already begun utilising IDS to define information requirements for automated code compliance checks. However, this requires the filtering of elements beyond the current scope of IDS. Such filtering functionality also has the potential to facilitate simple code compliance checks. This paper presents concepts for extending IDS to define information requirements for escape route analysis and code compliance checks for Austrian fire resistance regulations. The main extension was the filtering of elements depending on characteristics of related elements. Nesting existing functionalities enabled the schema to remain simple. A prototype implementation demonstrated that minor extensions to the IDS schema can significantly enhance its functionality, paving the way for broader applications of IDS.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"20 ","pages":"Article 100560"},"PeriodicalIF":6.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571711","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}
Pub Date : 2024-10-28DOI: 10.1016/j.dibe.2024.100565
I. Karatasios, S. Papaioannou, E. Tziviloglou, V. Kilikoglou
The aim of this work is the development of cementitious macro-capsules for self-healing cement and concrete materials. Emphasis is placed on shell properties, including size, thickness, strength, and volume to active component ratio. This enhancement is aimed at protecting the healing agent and ensuring adequate reactivity upon crack formation, surpassing survivability considerations. To this direction, core/shell particles have been produced following the pan-coating method, while different types and concentrations of setting acceleration solutions for the shell stabilization were studied. The formation of core-shell capsules encompasses the formation a spherical core through agglomeration, followed by simultaneous spraying of cement powder and a setting acceleration solution for the shell formation, under continuous rotation. The microstructural characteristics of the shell were studied through scanning electron microscopy (SEM), while the reactivity of the protected core (reactive agent) inside the hardened mortar mixtures was evaluated using thermogravimetric analysis (TGA). Moreover, the crushing load of the capsules under compression and their survivability during mixing process were examined and interpreted in relation to their diameter, circularity, and shell thickness.
The results revealed the ability of the encapsulation methodology proposed to tailor the shell properties and modify the capsule properties so as satisfy the requirements of different applications. The use of setting accelerators during shell formation proved essential for enhancing the density and the strength of the shell layer. As a consequence, this leads to macro-scale capsules with elevated survivability rate and core reactivity.
{"title":"Effect of shell composition on watertightness and mechanical performance of cement-based capsules used as self-healing additives of cement","authors":"I. Karatasios, S. Papaioannou, E. Tziviloglou, V. Kilikoglou","doi":"10.1016/j.dibe.2024.100565","DOIUrl":"10.1016/j.dibe.2024.100565","url":null,"abstract":"<div><div>The aim of this work is the development of cementitious macro-capsules for self-healing cement and concrete materials. Emphasis is placed on shell properties, including size, thickness, strength, and volume to active component ratio. This enhancement is aimed at protecting the healing agent and ensuring adequate reactivity upon crack formation, surpassing survivability considerations. To this direction, core/shell particles have been produced following the pan-coating method, while different types and concentrations of setting acceleration solutions for the shell stabilization were studied. The formation of core-shell capsules encompasses the formation a spherical core through agglomeration, followed by simultaneous spraying of cement powder and a setting acceleration solution for the shell formation, under continuous rotation. The microstructural characteristics of the shell were studied through scanning electron microscopy (SEM), while the reactivity of the protected core (reactive agent) inside the hardened mortar mixtures was evaluated using thermogravimetric analysis (TGA). Moreover, the crushing load of the capsules under compression and their survivability during mixing process were examined and interpreted in relation to their diameter, circularity, and shell thickness.</div><div>The results revealed the ability of the encapsulation methodology proposed to tailor the shell properties and modify the capsule properties so as satisfy the requirements of different applications. The use of setting accelerators during shell formation proved essential for enhancing the density and the strength of the shell layer. As a consequence, this leads to macro-scale capsules with elevated survivability rate and core reactivity.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"20 ","pages":"Article 100565"},"PeriodicalIF":6.2,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561028","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}
Pub Date : 2024-10-24DOI: 10.1016/j.dibe.2024.100564
Geon Noh , Gaurav Sharma , Hyeju Kim , Kunal Krishna Das , Jeong Gook Jang , Jung-Jun Park , Namkon Lee
This study investigates the physicochemical properties of CO2-cured belite-rich cement with electric arc furnace (EAF) reduction slag as a partial replacement at varying weight percentages (0–20%). The results revealed that water-cured specimens (WRS) showed significant increases in the numbers of gel and medium capillary pores, while carbonation-cured specimens (CRS) demonstrated increases in the numbers of large capillary and macro pores. Moreover, up to 10% replacement of the slag led to a decrease in the compressive strength, accompanied by increased CO2 absorption and reduced alkalinity. When the EAF reduction slag content increased from 15% to 20%, CRS exhibited a trend reversal in the compressive strength, marked by an increase in the pH, approaching compressive strength comparable to those of WRS. This signified that higher percentages of EAF reduction slag are advantageous for enhancing CO2 sequestration due to the potential reactivity of magnesium oxide in EAF reduction slag with CO2.
{"title":"Physicochemical properties of CO2-cured belite-rich cement with electric arc furnace reduction slag as a partial replacement","authors":"Geon Noh , Gaurav Sharma , Hyeju Kim , Kunal Krishna Das , Jeong Gook Jang , Jung-Jun Park , Namkon Lee","doi":"10.1016/j.dibe.2024.100564","DOIUrl":"10.1016/j.dibe.2024.100564","url":null,"abstract":"<div><div>This study investigates the physicochemical properties of CO<sub>2</sub>-cured belite-rich cement with electric arc furnace (EAF) reduction slag as a partial replacement at varying weight percentages (0–20%). The results revealed that water-cured specimens (WRS) showed significant increases in the numbers of gel and medium capillary pores, while carbonation-cured specimens (CRS) demonstrated increases in the numbers of large capillary and macro pores. Moreover, up to 10% replacement of the slag led to a decrease in the compressive strength, accompanied by increased CO<sub>2</sub> absorption and reduced alkalinity. When the EAF reduction slag content increased from 15% to 20%, CRS exhibited a trend reversal in the compressive strength, marked by an increase in the pH, approaching compressive strength comparable to those of WRS. This signified that higher percentages of EAF reduction slag are advantageous for enhancing CO<sub>2</sub> sequestration due to the potential reactivity of magnesium oxide in EAF reduction slag with CO<sub>2</sub>.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"20 ","pages":"Article 100564"},"PeriodicalIF":6.2,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529637","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}
Pub Date : 2024-10-24DOI: 10.1016/j.dibe.2024.100562
Kun Feng , David Hester , Su Taylor , Connor O'Higgins , Alan Ferguson , Zuo Zhu , Guang Zou , Myra Lydon , Juliana Early
In the context of improving resilience in transport infrastructure, an emerging approach of indirect structural health monitoring is gaining attention, known as drive-by monitoring, instrumenting a vehicle with sensors to evaluate the bridges it crosses. However, their effectiveness has predominantly been investigated in ideal scenarios, with actual real-world applications being quite scarce. The research presented in this paper explores the feasibility of combining two routes: (1) fleet emissions reduction and (2) transport resilience enhancement, through drive-by monitoring integrated with shared mobility, including electric mobility scooter and bicycle. The information from drive-by data collected from shared mobility can give valuable information on critical transport infrastructure (e.g., bridges) and such a drive-by database has the potential for network level infrastructure condition assessment. In this paper, two different drive-by roadmaps are investigated subject to the flexibility of the bridges, namely partially or fully drive-by monitoring. To validate the proposed roadmaps, a full-scale pedestrian bridge was chosen for drive-by testing, where smartphone sensors and specialised accelerometers are mounted on shared mobility for data acquisition. Experimental results demonstrate that (i) smartphone sensing can provide data with similar accuracy compared to specialised accelerometers, (ii) bridge frequencies can be easily obtained from temporarily parked shared mobility, with a maximum relative error of 1.05%, (iii) both the bridge frequencies and operational deflection shapes are successfully extracted from the moving shared mobility by using variational mode decomposition and filtering techniques, and shared mobility's GPS data along with moving speeds are collected for potential vehicle positioning and drive-by database updating.
{"title":"Experimental modal identification of a pedestrian bridge through drive-by monitoring integrated with shared-mobility vehicles","authors":"Kun Feng , David Hester , Su Taylor , Connor O'Higgins , Alan Ferguson , Zuo Zhu , Guang Zou , Myra Lydon , Juliana Early","doi":"10.1016/j.dibe.2024.100562","DOIUrl":"10.1016/j.dibe.2024.100562","url":null,"abstract":"<div><div>In the context of improving resilience in transport infrastructure, an emerging approach of indirect structural health monitoring is gaining attention, known as drive-by monitoring, instrumenting a vehicle with sensors to evaluate the bridges it crosses. However, their effectiveness has predominantly been investigated in ideal scenarios, with actual real-world applications being quite scarce. The research presented in this paper explores the feasibility of combining two routes: (1) fleet emissions reduction and (2) transport resilience enhancement, through drive-by monitoring integrated with shared mobility, including electric mobility scooter and bicycle. The information from drive-by data collected from shared mobility can give valuable information on critical transport infrastructure (e.g., bridges) and such a drive-by database has the potential for network level infrastructure condition assessment. In this paper, two different drive-by roadmaps are investigated subject to the flexibility of the bridges, namely partially or fully drive-by monitoring. To validate the proposed roadmaps, a full-scale pedestrian bridge was chosen for drive-by testing, where smartphone sensors and specialised accelerometers are mounted on shared mobility for data acquisition. Experimental results demonstrate that (i) smartphone sensing can provide data with similar accuracy compared to specialised accelerometers, (ii) bridge frequencies can be easily obtained from temporarily parked shared mobility, with a maximum relative error of 1.05%, (iii) both the bridge frequencies and operational deflection shapes are successfully extracted from the moving shared mobility by using variational mode decomposition and filtering techniques, and shared mobility's GPS data along with moving speeds are collected for potential vehicle positioning and drive-by database updating.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"20 ","pages":"Article 100562"},"PeriodicalIF":6.2,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538786","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}
Cemented lithium mica tailings backfill (CLMTB) faces dynamic loads from mining operations, affecting its stability. This study investigates the use of alkaline rice straw fibers (ARSF) to enhance CLMTB's dynamic properties. Dynamic impact tests were conducted on CLMTB specimens with varying ARSF contents, revealing that dynamic compressive strength (DCS) increased with ARSF up to 0.45% before decreasing. DCS improved with rising strain rates. The research includes analyses of stress-strain behavior, failure patterns, and energy dissipation during impacts, with scanning electron microscopy revealing the microstructural effects of ARSF on CLMTB. The findings suggest that ARSF effectively mitigates the damaging impacts of loads, significantly reducing crack development in CLMTB.
{"title":"Enhancing dynamic mechanical properties of cemented lithium mica tailings backfill with alkaline rice straw fibers: Experimental investigation and microscopic analysis","authors":"Daopei Zhu , Nanhui Huang , Quanmao Xiao , Zhangli Wang","doi":"10.1016/j.dibe.2024.100563","DOIUrl":"10.1016/j.dibe.2024.100563","url":null,"abstract":"<div><div>Cemented lithium mica tailings backfill (CLMTB) faces dynamic loads from mining operations, affecting its stability. This study investigates the use of alkaline rice straw fibers (ARSF) to enhance CLMTB's dynamic properties. Dynamic impact tests were conducted on CLMTB specimens with varying ARSF contents, revealing that dynamic compressive strength (DCS) increased with ARSF up to 0.45% before decreasing. DCS improved with rising strain rates. The research includes analyses of stress-strain behavior, failure patterns, and energy dissipation during impacts, with scanning electron microscopy revealing the microstructural effects of ARSF on CLMTB. The findings suggest that ARSF effectively mitigates the damaging impacts of loads, significantly reducing crack development in CLMTB.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"20 ","pages":"Article 100563"},"PeriodicalIF":6.2,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529585","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}
Pub Date : 2024-10-19DOI: 10.1016/j.dibe.2024.100559
Bin Yang, Hongru Xiao, Binghan Zhang
Accurately detecting whether workers wear Personal Protective Equipment (PPE) in real time plays an important role in safety management. Previous studies mainly used multiple models jointly or only object detection for wearing relationship judgments. This makes it difficult to provide real-time, accurate detection of security relationships. Therefore, this paper proposes safe-wearing detection rules and a novel multi-targets and keypoints detection framework (MTKF), which is capable of accomplishing multiple classes of targets and keypoints detection simultaneously in one-stage, to get more accurate results. In order to improve the performance in the PPE and worker keypoints detection in challenging construction scenes, the detection head transformation strategy, mix group shuffle attention (MGSA) module, and the improved dual and cross-class suppression algorithm (DC-NMS) are proposed. The experimental results are implemented on one established dataset (Joint dataset) and two public datasets (SHWD and COCO), which conduct a comprehensive evaluation in multiple dimensions. Compared to the baseline model, our method improves the mAP by 2.6%–7.1%, reduces the number of parameters by at least 70%, and is able to achieve an inference speed of 155 fps.
{"title":"A unified object and keypoint detection framework for Personal Protective Equipment use","authors":"Bin Yang, Hongru Xiao, Binghan Zhang","doi":"10.1016/j.dibe.2024.100559","DOIUrl":"10.1016/j.dibe.2024.100559","url":null,"abstract":"<div><div>Accurately detecting whether workers wear Personal Protective Equipment (PPE) in real time plays an important role in safety management. Previous studies mainly used multiple models jointly or only object detection for wearing relationship judgments. This makes it difficult to provide real-time, accurate detection of security relationships. Therefore, this paper proposes safe-wearing detection rules and a novel multi-targets and keypoints detection framework (MTKF), which is capable of accomplishing multiple classes of targets and keypoints detection simultaneously in one-stage, to get more accurate results. In order to improve the performance in the PPE and worker keypoints detection in challenging construction scenes, the detection head transformation strategy, mix group shuffle attention (MGSA) module, and the improved dual and cross-class suppression algorithm (DC-NMS) are proposed. The experimental results are implemented on one established dataset (Joint dataset) and two public datasets (SHWD and COCO), which conduct a comprehensive evaluation in multiple dimensions. Compared to the baseline model, our method improves the mAP by 2.6%–7.1%, reduces the number of parameters by at least 70%, and is able to achieve an inference speed of 155 fps.</div></div>","PeriodicalId":34137,"journal":{"name":"Developments in the Built Environment","volume":"20 ","pages":"Article 100559"},"PeriodicalIF":6.2,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529584","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}
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