Water-based HVAC systems exhibit strong thermal inertia distributed across the heat source, hydronic network, and building envelope, which can significantly affect model predictive control (MPC) performance if not properly represented. This paper develops a unified, control-oriented model that explicitly captures multi-stage thermal inertia into a linear state-space framework. A plant-side identification workflow is proposed that estimates the source time constant and network delay–attenuation using only routinely available supply and return water temperatures from an air-source heat pump district heating system (ASHP-DHS). The identified parameters are then embedded into an MPC formulation that regulates indoor temperature while limiting electrical power use and actuation variability. Closed-loop simulations compare four MPC configurations with different levels of inertia awareness. Results show that network-side inertia is the dominant factor for warm-up and cooldown behavior: neglecting distribution delay and attenuation leads to longer recovery times and larger temperature-tracking errors. Source-side inertia mainly shapes short-term electrical power ramps, with strong sensitivity when the source time constant is comparable to the control interval. Parameter sweeps further quantify how performance degrades as inertia parameters are mis-specified, providing practical guidance on when explicit multi-stage inertia modeling is essential for reliable control.
{"title":"Modeling and identification of multi-stage thermal inertia for reliable MPC in high-inertia water-based HVAC systems","authors":"Shuaihao Jiang, Huihui Song, Meng Liu, Fanqiang Meng, Liang Liu, Yanbin Qu","doi":"10.1016/j.jobe.2026.115620","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115620","url":null,"abstract":"Water-based HVAC systems exhibit strong thermal inertia distributed across the heat source, hydronic network, and building envelope, which can significantly affect model predictive control (MPC) performance if not properly represented. This paper develops a unified, control-oriented model that explicitly captures multi-stage thermal inertia into a linear state-space framework. A plant-side identification workflow is proposed that estimates the source time constant and network delay–attenuation using only routinely available supply and return water temperatures from an air-source heat pump district heating system (ASHP-DHS). The identified parameters are then embedded into an MPC formulation that regulates indoor temperature while limiting electrical power use and actuation variability. Closed-loop simulations compare four MPC configurations with different levels of inertia awareness. Results show that network-side inertia is the dominant factor for warm-up and cooldown behavior: neglecting distribution delay and attenuation leads to longer recovery times and larger temperature-tracking errors. Source-side inertia mainly shapes short-term electrical power ramps, with strong sensitivity when the source time constant is comparable to the control interval. Parameter sweeps further quantify how performance degrades as inertia parameters are mis-specified, providing practical guidance on when explicit multi-stage inertia modeling is essential for reliable control.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"8 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-14DOI: 10.1016/j.jobe.2026.115617
Iryna Osadcha, Egle Klumbyte, Andrius Jurelionis, Paulius Spudys, Timo Hartmann, Shayan Saket, Damian Harasymczuk, Paris Fokaides
{"title":"Retraction notice to ‘Towards interoperable building energy performance simulation: A digital Twin perspective’ [Journal of Building Engineering 110 (2025) 113059]","authors":"Iryna Osadcha, Egle Klumbyte, Andrius Jurelionis, Paulius Spudys, Timo Hartmann, Shayan Saket, Damian Harasymczuk, Paris Fokaides","doi":"10.1016/j.jobe.2026.115617","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115617","url":null,"abstract":"","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"18 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-14DOI: 10.1016/j.jobe.2026.115552
Ran Bir Singh, Ashish Kumar, Divya Sharma, Surya Kant Sahdeo
Concrete despite being the cornerstone of modern infrastructure has the tendency to crack because of its brittleness. In recent years, researchers have tried to reduce such issues by investigating microbial solutions. This research addresses one possible way of introducing bacterial strains into the concrete matrix, to remain dormant until the water penetrates the matrix. The bacteria (if activated) break-down calcium lactate and form calcium carbonate (CaCO3) which closes the cracks and makes the material more robust. In the present study, three bacterial isolates Escherichia coli, Bacillus subtilis and Streptomyces toxytricini were included into M25 grade concrete. Calcium lactate 5% was used as a constant nutrient source and different dosages of 3% and 6% (by cement weight) were tested. In addition, standardized mixing, casting, and curing procedures were adhered to. The study was conducted for determining the self-healing effectiveness, compressive strength and sorptivity with different curing regimes. The results demonstrated significant crack-healing ranged from approximately 89% to 97% after 28 days, depending on type of bacteria and curing. The highest compressive strength of 40 MPa was achieved with 6% Streptomyces toxytricini bacteria that showed an increase of 79% compared to controlled concrete. The lowest sorptivity value of 0.0007 mm/s1ᐟ2 was obtained for concrete containing 6% Streptomyces toxytricini that indicated improved resistance to long-term moisture ingress. The results showed that the addition of bacteria provided crack healing, enhanced compressive strength and significantly influenced the moisture absorption properties, thus showing the potential of bacterial concrete as a sustainable construction material.
{"title":"Experimental Investigation of Multi-Strain Bacterial Concrete: Self-Healing Efficiency, Strength, and Sorptivity under Varied Curing Conditions","authors":"Ran Bir Singh, Ashish Kumar, Divya Sharma, Surya Kant Sahdeo","doi":"10.1016/j.jobe.2026.115552","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115552","url":null,"abstract":"Concrete despite being the cornerstone of modern infrastructure has the tendency to crack because of its brittleness. In recent years, researchers have tried to reduce such issues by investigating microbial solutions. This research addresses one possible way of introducing bacterial strains into the concrete matrix, to remain dormant until the water penetrates the matrix. The bacteria (if activated) break-down calcium lactate and form calcium carbonate (CaCO<ce:inf loc=\"post\">3</ce:inf>) which closes the cracks and makes the material more robust. In the present study, three bacterial isolates Escherichia coli, Bacillus subtilis and Streptomyces toxytricini were included into M25 grade concrete. Calcium lactate 5% was used as a constant nutrient source and different dosages of 3% and 6% (by cement weight) were tested. In addition, standardized mixing, casting, and curing procedures were adhered to. The study was conducted for determining the self-healing effectiveness, compressive strength and sorptivity with different curing regimes. The results demonstrated significant crack-healing ranged from approximately 89% to 97% after 28 days, depending on type of bacteria and curing. The highest compressive strength of 40 MPa was achieved with 6% Streptomyces toxytricini bacteria that showed an increase of 79% compared to controlled concrete. The lowest sorptivity value of 0.0007 mm/s<ce:sup loc=\"post\">1</ce:sup>ᐟ<ce:sup loc=\"post\">2</ce:sup> was obtained for concrete containing 6% Streptomyces toxytricini that indicated improved resistance to long-term moisture ingress. The results showed that the addition of bacteria provided crack healing, enhanced compressive strength and significantly influenced the moisture absorption properties, thus showing the potential of bacterial concrete as a sustainable construction material.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"1 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-14DOI: 10.1016/j.jobe.2026.115519
Xuan Dong, Weiqi Guo, Jianghua Deng, Pei Ge, Zhiheng Liu
This study presents a dual-scale damage framework for modeling freeze–thaw degradation in cement-based materials by fully coupling thermo-hydro-mechanical (THM) freezing processes with a micromechanics-informed damage formulation. In contrast to conventional scalar-damage approaches, a second-order damage tensor is introduced to describe the evolution of damage-induced anisotropy in both stiffness and permeability. The coupled THM fields drive subcritical microcrack growth, whereas the evolving damage feeds back to update the effective material properties, thereby establishing a consistent micro–macro linkage. The framework is validated against experimental measurements of mechanical responses before and after freeze–thaw cycling. High agreement is obtained for the undamaged condition (R2=0.976), and the predictive performance remains strong after 25 freeze–thaw cycles (R2=0.935). In addition, the predicted damage evolution closely follows the cumulative acoustic emission energy trend (Spearman’s ρ=0.990). Simulations further indicate an approximately 10.5% increase in permeability after 30 cycles, underscoring pronounced localization and anisotropy of transport enhancement induced by freeze–thaw microcracking. Overall, the proposed framework offers a physically grounded route for linking microscopic crack evolution to macroscopic deterioration and enables mechanism-informed prediction of freeze–thaw performance.
{"title":"A dual-scale damage model for freezing–thaw degradation in cement-based materials under thermo-hydro-mechanical coupling","authors":"Xuan Dong, Weiqi Guo, Jianghua Deng, Pei Ge, Zhiheng Liu","doi":"10.1016/j.jobe.2026.115519","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115519","url":null,"abstract":"This study presents a dual-scale damage framework for modeling freeze–thaw degradation in cement-based materials by fully coupling thermo-hydro-mechanical (THM) freezing processes with a micromechanics-informed damage formulation. In contrast to conventional scalar-damage approaches, a second-order damage tensor is introduced to describe the evolution of damage-induced anisotropy in both stiffness and permeability. The coupled THM fields drive subcritical microcrack growth, whereas the evolving damage feeds back to update the effective material properties, thereby establishing a consistent micro–macro linkage. The framework is validated against experimental measurements of mechanical responses before and after freeze–thaw cycling. High agreement is obtained for the undamaged condition (<mml:math altimg=\"si3.svg\" display=\"inline\"><mml:mrow><mml:msup><mml:mrow><mml:mi>R</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup><mml:mo linebreak=\"goodbreak\" linebreakstyle=\"after\">=</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:mn>976</mml:mn></mml:mrow></mml:math>), and the predictive performance remains strong after 25 freeze–thaw cycles (<mml:math altimg=\"si4.svg\" display=\"inline\"><mml:mrow><mml:msup><mml:mrow><mml:mi>R</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup><mml:mo linebreak=\"goodbreak\" linebreakstyle=\"after\">=</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:mn>935</mml:mn></mml:mrow></mml:math>). In addition, the predicted damage evolution closely follows the cumulative acoustic emission energy trend (Spearman’s <mml:math altimg=\"si318.svg\" display=\"inline\"><mml:mrow><mml:mi>ρ</mml:mi><mml:mo linebreak=\"goodbreak\" linebreakstyle=\"after\">=</mml:mo><mml:mn>0</mml:mn><mml:mo>.</mml:mo><mml:mn>990</mml:mn></mml:mrow></mml:math>). Simulations further indicate an approximately 10.5% increase in permeability after 30 cycles, underscoring pronounced localization and anisotropy of transport enhancement induced by freeze–thaw microcracking. Overall, the proposed framework offers a physically grounded route for linking microscopic crack evolution to macroscopic deterioration and enables mechanism-informed prediction of freeze–thaw performance.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"95 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-14DOI: 10.1016/j.jobe.2026.115622
Hu Xu, Zihan Cao, Jiaxu Wu, Qingliang Zhan
This study proposes a novel composite beam system in which a ribbed ultra-high-performance concrete (UHPC) precast shell acts synergistically as both permanent formwork and a primary shear-resisting component, thereby reducing reliance on conventional stirrups. To investigate its shear performance, four beam specimens—one conventional RC beam and three UHPC-NC composite beams with varying stirrup ratios (0.177%–0.491%)—were tested under shear loading. Results showed that the UHPC shell significantly enhanced cracking resistance (first crack load increased by 100%–250%) and shear capacity (peak load improved by 37.6%–54.1% compared to the RC beam). Notably, with a 44% lower stirrup ratio (0.177% vs. 0.314%), the composite beam still achieved a 37.6% higher peak load, demonstrating the substantial shear contribution of the UHPC shell. The system also transformed failure from brittle to ductile, promoting distributed cracking and stable post-peak behavior. These findings validate the dual advantage of the proposed system: facilitating construction through lightweight precast elements and enabling the design of more resilient and economical shear-critical members, thus supporting the development of performance-based design guidelines.
本研究提出了一种新型复合梁系统，其中带肋超高性能混凝土（UHPC）预制壳作为永久模板和主要抗剪构件协同作用，从而减少了对传统箍筋的依赖。为研究其抗剪性能，分别对1根普通RC梁和3根不同配箍率（0.177% ~ 0.491%）的UHPC-NC组合梁进行了抗剪试验。结果表明：与RC梁相比，UHPC壳的抗裂能力（首裂荷载提高100% ~ 250%）和抗剪能力（峰值荷载提高37.6% ~ 54.1%）显著提高；值得注意的是，在箍筋比降低44% （0.177% vs 0.314%）的情况下，组合梁的峰值荷载仍然高出37.6%，这表明了UHPC壳对剪切的巨大贡献。该系统还将破坏从脆性转变为延性，促进了分布式开裂和稳定的峰后行为。这些发现验证了所提出的系统的双重优势：通过轻质预制件促进施工，使设计更具弹性和经济的剪切临界构件成为可能，从而支持基于性能的设计指南的发展。
{"title":"Shear behavior of composite beams using UHPC precast shell as permanent formwork","authors":"Hu Xu, Zihan Cao, Jiaxu Wu, Qingliang Zhan","doi":"10.1016/j.jobe.2026.115622","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115622","url":null,"abstract":"This study proposes a novel composite beam system in which a ribbed ultra-high-performance concrete (UHPC) precast shell acts synergistically as both permanent formwork and a primary shear-resisting component, thereby reducing reliance on conventional stirrups. To investigate its shear performance, four beam specimens—one conventional RC beam and three UHPC-NC composite beams with varying stirrup ratios (0.177%–0.491%)—were tested under shear loading. Results showed that the UHPC shell significantly enhanced cracking resistance (first crack load increased by 100%–250%) and shear capacity (peak load improved by 37.6%–54.1% compared to the RC beam). Notably, with a 44% lower stirrup ratio (0.177% vs. 0.314%), the composite beam still achieved a 37.6% higher peak load, demonstrating the substantial shear contribution of the UHPC shell. The system also transformed failure from brittle to ductile, promoting distributed cracking and stable post-peak behavior. These findings validate the dual advantage of the proposed system: facilitating construction through lightweight precast elements and enabling the design of more resilient and economical shear-critical members, thus supporting the development of performance-based design guidelines.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"45 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-14DOI: 10.1016/j.jobe.2026.115619
Fadi Althoey, Osama Zaid, Jesús de-Prado-Gil, Covadonga Palencia, Elias Ali, Ibrahim Hakeem, Rebeca Martínez-García
{"title":"Retraction notice to ‘Impact of sulfate activation of rice husk ash on the performance of high strength steel fiber reinforced recycled aggregate concrete’ [J. Build Eng. 54 (2022) 104610]","authors":"Fadi Althoey, Osama Zaid, Jesús de-Prado-Gil, Covadonga Palencia, Elias Ali, Ibrahim Hakeem, Rebeca Martínez-García","doi":"10.1016/j.jobe.2026.115619","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115619","url":null,"abstract":"","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"3 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-14DOI: 10.1016/j.jobe.2026.115601
Ping Li, Jie Wei, Jian Liu, Xuejie Zhang, Jun Li
Web openings are commonly introduced in reinforced concrete (RC) beams to accommodate building services, yet, under impact loading, these openings often become weak regions due to reduced stiffness and load-carrying capacity resulting from geometric discontinuities and stress concentrations. Despite their prevalence, the impact behaviour of RC beams with such openings has not been understood, and the potential of ultra-high performance concrete (UHPC), with its superior strength, durability, and damage resistance, to mitigate these vulnerabilities remains largely unexplored. This study experimentally and numerically investigates the dynamic performance of UHPC beams with rectangular web openings under low-velocity impact loads. Drop-weight impact tests were performed on one solid UHPC beam and four UHPC beams with varying opening configurations. The results revealed that the presence of openings altered crack propagation paths and increased mid-span deflections relative to the solid beam, whereas additional transverse reinforcement around the openings effectively enhanced the impact resistance. Subsequently, numerical models were established in ANSYS/LS-DYNA and validated by the experimental observations. The validated models were further utilised for parametric analyses, which indicated that as the distance between the opening and the impact location increased, the maximum and residual mid-span deflections initially decreased and then increased. Based on these findings, recommendations for determining opening configurations were proposed, and mass-velocity diagrams were established to facilitate rapid damage assessment of UHPC beams incorporating the recommended opening configurations.
{"title":"Assessment of low-velocity impact response in ultra-high performance concrete (UHPC) beams with rectangular web openings: Experimental observations and numerical modelling","authors":"Ping Li, Jie Wei, Jian Liu, Xuejie Zhang, Jun Li","doi":"10.1016/j.jobe.2026.115601","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115601","url":null,"abstract":"Web openings are commonly introduced in reinforced concrete (RC) beams to accommodate building services, yet, under impact loading, these openings often become weak regions due to reduced stiffness and load-carrying capacity resulting from geometric discontinuities and stress concentrations. Despite their prevalence, the impact behaviour of RC beams with such openings has not been understood, and the potential of ultra-high performance concrete (UHPC), with its superior strength, durability, and damage resistance, to mitigate these vulnerabilities remains largely unexplored. This study experimentally and numerically investigates the dynamic performance of UHPC beams with rectangular web openings under low-velocity impact loads. Drop-weight impact tests were performed on one solid UHPC beam and four UHPC beams with varying opening configurations. The results revealed that the presence of openings altered crack propagation paths and increased mid-span deflections relative to the solid beam, whereas additional transverse reinforcement around the openings effectively enhanced the impact resistance. Subsequently, numerical models were established in ANSYS/LS-DYNA and validated by the experimental observations. The validated models were further utilised for parametric analyses, which indicated that as the distance between the opening and the impact location increased, the maximum and residual mid-span deflections initially decreased and then increased. Based on these findings, recommendations for determining opening configurations were proposed, and mass-velocity diagrams were established to facilitate rapid damage assessment of UHPC beams incorporating the recommended opening configurations.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"413 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-14DOI: 10.1016/j.jobe.2026.115537
Ruitian Xu, Zongping Chen, Fan Ning, Xuemei Liu
To investigate the influence of spiral stirrups on the seismic performance of recycled aggregate concrete (RAC) frames, a two-story, two-span frame composed of spiral-stirrup RAC columns and original reinforcement RAC beams was designed and fabricated based on a prototype engineering structure. Low-cycle reversed loading tests and finite element simulations were conducted. The experimental study examined the failure process, hysteretic behavior, load-bearing capacity, ductility, energy dissipation, and stiffness degradation of the frame. Furthermore, the finite element analysis was used to explore the seismic response of the frame under different structural parameters and ground motion intensities. The results indicate that the spiral stirrups adopted in the column and joint core regions provided continuous and uniform lateral confinement in the joint core and column base regions, effectively suppressing crack propagation and concrete spalling while delaying the development of plastic damage. Consequently, the frame exhibited stable load-carrying capacity after yielding, full and stable hysteretic loops, and enhanced energy dissipation and ductility. Time-history analyses further revealed that the presence of spiral-stirrup columns contributed to improved the lateral stiffness of the frame under seismic excitation. The maximum interstory drift ratio remained below the code limit, and the peak roof acceleration increased gradually with seismic intensity but stayed within a reasonable range. Overall, the frame demonstrated satisfactory seismic performance. The findings of this study provide a scientific basis for the wider application of RAC in seismic-resistant frame structures and for the refinement of relevant design codes.
{"title":"Experimental investigation on the seismic behavior of recycled aggregate concrete frames with spiral-stirrup columns and original reinforced beams","authors":"Ruitian Xu, Zongping Chen, Fan Ning, Xuemei Liu","doi":"10.1016/j.jobe.2026.115537","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115537","url":null,"abstract":"To investigate the influence of spiral stirrups on the seismic performance of recycled aggregate concrete (RAC) frames, a two-story, two-span frame composed of spiral-stirrup RAC columns and original reinforcement RAC beams was designed and fabricated based on a prototype engineering structure. Low-cycle reversed loading tests and finite element simulations were conducted. The experimental study examined the failure process, hysteretic behavior, load-bearing capacity, ductility, energy dissipation, and stiffness degradation of the frame. Furthermore, the finite element analysis was used to explore the seismic response of the frame under different structural parameters and ground motion intensities. The results indicate that the spiral stirrups adopted in the column and joint core regions provided continuous and uniform lateral confinement in the joint core and column base regions, effectively suppressing crack propagation and concrete spalling while delaying the development of plastic damage. Consequently, the frame exhibited stable load-carrying capacity after yielding, full and stable hysteretic loops, and enhanced energy dissipation and ductility. Time-history analyses further revealed that the presence of spiral-stirrup columns contributed to improved the lateral stiffness of the frame under seismic excitation. The maximum interstory drift ratio remained below the code limit, and the peak roof acceleration increased gradually with seismic intensity but stayed within a reasonable range. Overall, the frame demonstrated satisfactory seismic performance. The findings of this study provide a scientific basis for the wider application of RAC in seismic-resistant frame structures and for the refinement of relevant design codes.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"11 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-13DOI: 10.1016/j.jobe.2026.115561
Saleh ali Khawaja, Million Tafesse, Hang Zeng, Hee-Jeong Kim
Theoretically, mine tailings satisfy the chemical requirements to be classified as a pozzolanic material under ASTM C618 due to the presence of substantial silica, alumina, and iron oxides. However, the oxides bearing phases in tailings are highly crystalline, making tailings an inert waste material. The reactive phase formation and phase transformation through thermal and mechanical activation of gold mine tailing (GMT) were investigated and quantified using integrated Confocal Raman microscopy (CRM) with Quantitative-XRD. The enhancement in reactivity performance of activated GMTs were evaluated through the modified strength activity index test, and their contribution to hydration reaction was further validated using TGA and water-bound test. CRM analysis of modified R3 reactivity samples identified the AFm hydration phases with in-situ Raman mapping and 2D phase mapping, revealing temporal growth of hydration products. The results indicate that 800 °C-treated GMT enhances reactivity by promoting phase transformation and the formation of new reactive phases, such as Anhydrite. The activation at higher temperatures increased the amorphous content; however, sintering became more pronounced at higher temperatures, and the reactivity decreased. Overall, this study establishes an optimal activation condition for the reactivity.
{"title":"New insights into phase transformation and reactivity of gold mine tailings through integrated Raman spectroscopy and quantitative XRD analysis","authors":"Saleh ali Khawaja, Million Tafesse, Hang Zeng, Hee-Jeong Kim","doi":"10.1016/j.jobe.2026.115561","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115561","url":null,"abstract":"Theoretically, mine tailings satisfy the chemical requirements to be classified as a pozzolanic material under ASTM C618 due to the presence of substantial silica, alumina, and iron oxides. However, the oxides bearing phases in tailings are highly crystalline, making tailings an inert waste material. The reactive phase formation and phase transformation through thermal and mechanical activation of gold mine tailing (GMT) were investigated and quantified using integrated Confocal Raman microscopy (CRM) with Quantitative-XRD. The enhancement in reactivity performance of activated GMTs were evaluated through the modified strength activity index test, and their contribution to hydration reaction was further validated using TGA and water-bound test. CRM analysis of modified R3 reactivity samples identified the AFm hydration phases with in-situ Raman mapping and 2D phase mapping, revealing temporal growth of hydration products. The results indicate that 800 °C-treated GMT enhances reactivity by promoting phase transformation and the formation of new reactive phases, such as Anhydrite. The activation at higher temperatures increased the amorphous content; however, sintering became more pronounced at higher temperatures, and the reactivity decreased. Overall, this study establishes an optimal activation condition for the reactivity.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"4 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the contributions of physical packing and chemical reactions to the performance of UHPC are investigated by using machine learning and thermodynamic calculations. The results show that the contribution degree of them to the strength of UHPC at various ages is different. The early strength is determined by the cement hydration, while the growth rate of the strength of the mixtures is a combination of chemical reactions and physical packing, which also determines the later strength of the UHPC. Taking UHPC with the formulation of LP50 as an example, the normalized contribution of physical packing and chemical reactions to the 28-day compressive strength is in the range of 0.45-0.70 and 0.30-0.55, respectively.
{"title":"Study on the contribution of physical packing and chemical reactions to the mechanical properties of UHPC","authors":"Guangshao Yang, Qihao Ran, Rui Yu, Jiasheng Wu, Xin Zuo, Rengui Xiao, Xiang Ke, Zhiyang Wang, Rui Yang","doi":"10.1016/j.jobe.2026.115590","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115590","url":null,"abstract":"In this study, the contributions of physical packing and chemical reactions to the performance of UHPC are investigated by using machine learning and thermodynamic calculations. The results show that the contribution degree of them to the strength of UHPC at various ages is different. The early strength is determined by the cement hydration, while the growth rate of the strength of the mixtures is a combination of chemical reactions and physical packing, which also determines the later strength of the UHPC. Taking UHPC with the formulation of LP50 as an example, the normalized contribution of physical packing and chemical reactions to the 28-day compressive strength is in the range of 0.45-0.70 and 0.30-0.55, respectively.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"321 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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