Journal of building engineering最新文献

Performance-based optimization of steel exoskeletons: An alternative approach to standard regulations

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering

Pub Date : 2025-03-05 DOI: 10.1016/j.jobe.2025.112177

Raffaele Cucuzza , Jana Olivo , Gabriele Bertagnoli , Giuseppe Andrea Ferro , Giuseppe Carlo Marano

Among the various seismic retrofitting techniques, steel exoskeletons are distinguished as a valuable retrofitting approach to mitigate structural vulnerability under lateral loads while simultaneously preserving the buildings’ functionality and activities’ full operability. However, they are not a commonly selected option by designers, as several standard regulations recommend a design approach based on the relative stiffness between the exoskeletons and the building. They establish a restrictive limit for this ratio, resulting in costly and heavy designs. This paper proposes a paradigm shift in exoskeleton design, moving from the control of the stiffness ratio to a performance-based design approach. Different inter-story drift thresholds are adopted as performance constraints of an innovative optimized design procedure where the number, position, and sizing of the exoskeletons are assumed as design variables. Based on the outcomes of the optimization processes conducted on three real-world inspired case studies, a sensitivity analysis is performed. In all scenarios, the results demonstrate that the performance-based approach allows for greater utilization of the building’s capacity in the elastic field to resist horizontal actions while preserving structural safety. Consequently, in contrast with the conservative designs obtained following standard regulations, the proposed approach leads to lighter and more economically efficient designs, which make the exoskeletons a more attractive alternative.

{"title":"Performance-based optimization of steel exoskeletons: An alternative approach to standard regulations","authors":"Raffaele Cucuzza , Jana Olivo , Gabriele Bertagnoli , Giuseppe Andrea Ferro , Giuseppe Carlo Marano","doi":"10.1016/j.jobe.2025.112177","DOIUrl":"10.1016/j.jobe.2025.112177","url":null,"abstract":"<div><div>Among the various seismic retrofitting techniques, steel exoskeletons are distinguished as a valuable retrofitting approach to mitigate structural vulnerability under lateral loads while simultaneously preserving the buildings’ functionality and activities’ full operability. However, they are not a commonly selected option by designers, as several standard regulations recommend a design approach based on the relative stiffness between the exoskeletons and the building. They establish a restrictive limit for this ratio, resulting in costly and heavy designs. This paper proposes a paradigm shift in exoskeleton design, moving from the control of the stiffness ratio to a performance-based design approach. Different inter-story drift thresholds are adopted as performance constraints of an innovative optimized design procedure where the number, position, and sizing of the exoskeletons are assumed as design variables. Based on the outcomes of the optimization processes conducted on three real-world inspired case studies, a sensitivity analysis is performed. In all scenarios, the results demonstrate that the performance-based approach allows for greater utilization of the building’s capacity in the elastic field to resist horizontal actions while preserving structural safety. Consequently, in contrast with the conservative designs obtained following standard regulations, the proposed approach leads to lighter and more economically efficient designs, which make the exoskeletons a more attractive alternative.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"104 ","pages":"Article 112177"},"PeriodicalIF":6.7,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562910","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}

引用次数: 0

Experimental investigation on a novel spray-medium pad coupled two-stage evaporative cooling system to enhance heat and moisture transfer performance

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering

Pub Date : 2025-03-05 DOI: 10.1016/j.jobe.2025.112275

Mingcai Yu, Liang Zhang, Qi Fang, Yu Lin, Rui Li

Lowering the air temperature using evaporative cooling technology is an effective way to enhance the performance of an air-cooled chiller system and hence achieve electric savings. Application of the spray cooling and the wet medium is limited because of low cooling efficiency and high water consumption, respectively. A novel two-stage evaporative cooling system (SMEC), with the coupling of spray and medium pad, has been proposed to overcome these limitations. An experimental platform was set up to test cooling and humidification performance, analyzing the effects of inlet air relative humidity, velocity, and spray flow rate. At 35 °C and 50 % humidity, SMEC can reduce temperature by 7.4 °C with 81.3 % evaporative cooling efficiency. The cooling efficiency is improved by more than 8.3 % compared to a single medium pad and 11.6 % compared to a single spray by SMEC. Higher efficiency is achievable with a thinner medium pad and less water usage. Additionally, the cooling and humidification performance of the SMEC is found to decrease with increasing inlet air relative humidity and velocity, while it is observed to increase with increasing spray flow rate. The cooling capacity and coefficient of performance (COP) are found to decrease with increasing inlet relative humidity and to increase with increasing inlet air velocity. The cooling capacity is observed to increase with increasing spray flow rate. Compared with a single medium cooling system, the COP of the SMEC system increased by 10.7 %.

{"title":"Experimental investigation on a novel spray-medium pad coupled two-stage evaporative cooling system to enhance heat and moisture transfer performance","authors":"Mingcai Yu, Liang Zhang, Qi Fang, Yu Lin, Rui Li","doi":"10.1016/j.jobe.2025.112275","DOIUrl":"10.1016/j.jobe.2025.112275","url":null,"abstract":"<div><div>Lowering the air temperature using evaporative cooling technology is an effective way to enhance the performance of an air-cooled chiller system and hence achieve electric savings. Application of the spray cooling and the wet medium is limited because of low cooling efficiency and high water consumption, respectively. A novel two-stage evaporative cooling system (SMEC), with the coupling of spray and medium pad, has been proposed to overcome these limitations. An experimental platform was set up to test cooling and humidification performance, analyzing the effects of inlet air relative humidity, velocity, and spray flow rate. At 35 °C and 50 % humidity, SMEC can reduce temperature by 7.4 °C with 81.3 % evaporative cooling efficiency. The cooling efficiency is improved by more than 8.3 % compared to a single medium pad and 11.6 % compared to a single spray by SMEC. Higher efficiency is achievable with a thinner medium pad and less water usage. Additionally, the cooling and humidification performance of the SMEC is found to decrease with increasing inlet air relative humidity and velocity, while it is observed to increase with increasing spray flow rate. The cooling capacity and coefficient of performance (COP) are found to decrease with increasing inlet relative humidity and to increase with increasing inlet air velocity. The cooling capacity is observed to increase with increasing spray flow rate. Compared with a single medium cooling system, the COP of the SMEC system increased by 10.7 %.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"104 ","pages":"Article 112275"},"PeriodicalIF":6.7,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562911","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}

引用次数: 0

Enhancing the fracture performance of cementitious composites through synergistic integration of graphene with polyolefin and polyvinyl alcohol fibres

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering

Pub Date : 2025-03-05 DOI: 10.1016/j.jobe.2025.112273

Shahzad Ashraf, Magdalena Rucka

Polyvinyl alcohol fibre (PVA) and polyolefin fibre (PO) are utilized in engineering cementitious composites (ECCs) due to their excellent crack-bridging capabilities, durability, ductility and energy absorption capacity. However, their combined effects on crack propagation mechanism, especially when combined with nano-reinforcement, remain underexplored. Recently, graphene nanoplatelets (GNPs) have emerged as promising nano-reinforcement in composite materials for enhancing the mechanical, thermal, and crack propagation resistance. Based on this premise, this study investigates the synergistic effects of GNPs combined with single and hybrid fibre reinforcement of PO-PVA at varying dosages (0.1 vol%, 0.3 vol%, and 0.6 vol%), aiming to improve the fracture performance of cementitious composites. Three-point bending tests were conducted using the AE technique to monitor crack initiation and propagation, allowing an in-depth analysis of crack evolution characteristics. By employing various AE parameters and advanced AE analysis methods, this research captures critical insights into microcracking events, fracture mechanisms, and failure modes in single and hybrid- PO-PVA fibre-reinforced composites containing GNPs. The research identifies the most beneficial concrete mix designs that significantly enhances interfacial bonding, microstructural integrity and fracture performance. Furthermore, the hybridisation of PVA-PO-GNPs leads to a notable shift in the dominant fracture mode towards shear cracks. This study findings are expected to provide novel insights into the optimization of FRC enhanced with nanomaterials, paving the way for innovative applications in advancing high-performance engineering structures with improved fracture resistance.

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引用次数: 0

Prediction of long-period ground motion responses for high-rise buildings using physics-assisted fully convolutional neural network

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering

Pub Date : 2025-03-04 DOI: 10.1016/j.jobe.2025.112264

Yan Jiang , Beilong Luo , Yuan Jiang , Min Liu , Shuoyu Liu , Liuliu Peng

Far-field long-period ground motions (LPGMs) have a significant long-duration characteristic and can cause severe damages to high-rise buildings in the LPGM potential area. Rapid and accurate prediction of LPGM-induced responses is crucial for earthquake emergency management and loss assessment in large cities. However, dynamic-based methods for calculating structural responses involve intricate physical modeling process, resulting in low computational efficiency and failing to meet the prediction timeliness requirement. Furthermore, current data-driven methods cannot satisfy the prediction accuracy requirement due to the harsh formation condition causing scarcity and particularity of LPGM records. To this end, this paper develops a physics-assisted fully convolutional neural network (PhyFCN) for predicting LPGM-induced response of high-rise buildings. Central to this method lies in encoding the complex seismic motion equation into FCN for formulating an innovative physical loss function. The utilization of this function not only significantly enhances the prediction accuracy and robustness, but also remarkably reduces the dependence on the large number of training samples, i.e., a small number of training samples is sufficient for acquiring the desired parameters. This method integrates strengths of both dynamic-based methods and data-driven methods, enabling it to simultaneously fulfill requirements of prediction timeliness and accuracy. Numerical examples based on two different buildings are employed to verify the effectiveness and superiority of PhyFCN. Results suggest that the incorporation of the physics-assisted mechanism into FCN, even when only one training sample is available, can sharply increase the R value by 28.4 %, while those of MSE and MAE are decreased by 60.2 % and 37.6 %, respectively.

{"title":"Prediction of long-period ground motion responses for high-rise buildings using physics-assisted fully convolutional neural network","authors":"Yan Jiang , Beilong Luo , Yuan Jiang , Min Liu , Shuoyu Liu , Liuliu Peng","doi":"10.1016/j.jobe.2025.112264","DOIUrl":"10.1016/j.jobe.2025.112264","url":null,"abstract":"<div><div>Far-field long-period ground motions (LPGMs) have a significant long-duration characteristic and can cause severe damages to high-rise buildings in the LPGM potential area. Rapid and accurate prediction of LPGM-induced responses is crucial for earthquake emergency management and loss assessment in large cities. However, dynamic-based methods for calculating structural responses involve intricate physical modeling process, resulting in low computational efficiency and failing to meet the prediction timeliness requirement. Furthermore, current data-driven methods cannot satisfy the prediction accuracy requirement due to the harsh formation condition causing scarcity and particularity of LPGM records. To this end, this paper develops a physics-assisted fully convolutional neural network (PhyFCN) for predicting LPGM-induced response of high-rise buildings. Central to this method lies in encoding the complex seismic motion equation into FCN for formulating an innovative physical loss function. The utilization of this function not only significantly enhances the prediction accuracy and robustness, but also remarkably reduces the dependence on the large number of training samples, i.e., a small number of training samples is sufficient for acquiring the desired parameters. This method integrates strengths of both dynamic-based methods and data-driven methods, enabling it to simultaneously fulfill requirements of prediction timeliness and accuracy. Numerical examples based on two different buildings are employed to verify the effectiveness and superiority of PhyFCN. Results suggest that the incorporation of the physics-assisted mechanism into FCN, even when only one training sample is available, can sharply increase the R value by 28.4 %, while those of MSE and MAE are decreased by 60.2 % and 37.6 %, respectively.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"104 ","pages":"Article 112264"},"PeriodicalIF":6.7,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563033","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}

引用次数: 0

Fragility analysis of heritage masonry buildings accounting for ageing effects

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering

Pub Date : 2025-03-04 DOI: 10.1016/j.jobe.2025.112267

Paraskevi P. Kafetzi , Vassilis K. Papanikolaou , Andreas J. Kappos

A methodology is presented for assessing the time (age) dependent seismic fragility of heritage buildings, an issue that has hardly been addressed so far. Age effects are explicitly considered for the parameters (compression strength and shear strength of masonry) for which the available data permits the development of time-dependent models, while effects on stiffness and deformation parameters are accounted for in an indirect way. The methodology entails response history analysis of three-dimensional models of the masonry building and assignment to a damage state by appropriately interpreting the deformations of critical zones calculated from the analysis. The methodology is applied to an actual heritage building located in a high seismicity area (Greece). Sets of fragility curves are derived using alternative assumptions for key parameters related to the definition of global damage state for the building, and recommendations are made for future research needed on this topic that is particularly important for the preservation of cultural heritage in an era wherein environmental conditions become more challenging.

本文提出了一种评估文物建筑随时间（年代）变化的抗震脆性的方法，迄今为止，这个问题几乎没有得到解决。对于参数（砌体的抗压强度和抗剪强度），明确考虑了年代效应，因为现有数据允许建立随时间变化的模型，而对刚度和变形参数的影响则以间接方式考虑。该方法需要对砌体建筑的三维模型进行响应历史分析，并通过对分析计算出的临界区变形进行适当解释来确定破坏状态。该方法适用于位于地震高发区（希腊）的实际遗产建筑。通过对与建筑物全球破坏状态定义相关的关键参数进行替代假设，得出了多组脆性曲线，并就该课题未来需要开展的研究提出了建议，在环境条件变得更具挑战性的时代，该课题对文化遗产保护尤为重要。

{"title":"Fragility analysis of heritage masonry buildings accounting for ageing effects","authors":"Paraskevi P. Kafetzi , Vassilis K. Papanikolaou , Andreas J. Kappos","doi":"10.1016/j.jobe.2025.112267","DOIUrl":"10.1016/j.jobe.2025.112267","url":null,"abstract":"<div><div>A methodology is presented for assessing the time (age) dependent seismic fragility of heritage buildings, an issue that has hardly been addressed so far. Age effects are explicitly considered for the parameters (compression strength and shear strength of masonry) for which the available data permits the development of time-dependent models, while effects on stiffness and deformation parameters are accounted for in an indirect way. The methodology entails response history analysis of three-dimensional models of the masonry building and assignment to a damage state by appropriately interpreting the deformations of critical zones calculated from the analysis. The methodology is applied to an actual heritage building located in a high seismicity area (Greece). Sets of fragility curves are derived using alternative assumptions for key parameters related to the definition of global damage state for the building, and recommendations are made for future research needed on this topic that is particularly important for the preservation of cultural heritage in an era wherein environmental conditions become more challenging.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"104 ","pages":"Article 112267"},"PeriodicalIF":6.7,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563034","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}

引用次数: 0

Evaluating earthquake-induced damage in Dogansehir, Malatya after 2023 Kahramanmaras Earthquake sequence: Geotechnical and structural perspectives

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering

Pub Date : 2025-03-04 DOI: 10.1016/j.jobe.2025.112266

Ibrahim O. Dedeoglu , Musa Yetkin , Gülen Tunc , Osman E. Ozbulut

On February 6, 2023, two major earthquakes with magnitudes M_w = 7.7 and M_w = 7.6 struck southeastern Turkiye, causing catastrophic damage and loss of life across 11 provinces, including Malatya. This study focuses on documenting the geotechnical observations and structural damage in Dogansehir, one of the hardest-hit districts not only in Malatya but in the entire affected region. An overview of the -region's tectonic and geological background is presented, followed by an analysis of ground motion data specific to Malatya. A detailed examination of seismic data from stations near Dogansehir was provided to better understand the seismic demands during the earthquakes. The paper then provides insights into the geotechnical conditions, building characteristics, and a damage ratio map of Dogansehir. The influence of local tectonics and geology on the observed damage is analyzed, alongside an evaluation of the seismic performance of masonry and reinforced concrete structures. Dogansehir, located near the epicenters of the Kahramanmaras earthquakes, suffered major structural damage. This was due to the surface rupture occurring near the settlement areas, the establishment of the district centre on the alluvial soil layer and the deficiencies/errors in the building systems. Building settlements on or near active fault zones, as well as on soft soil, leads to serious consequences and should be avoided or require special precautions.

{"title":"Evaluating earthquake-induced damage in Dogansehir, Malatya after 2023 Kahramanmaras Earthquake sequence: Geotechnical and structural perspectives","authors":"Ibrahim O. Dedeoglu , Musa Yetkin , Gülen Tunc , Osman E. Ozbulut","doi":"10.1016/j.jobe.2025.112266","DOIUrl":"10.1016/j.jobe.2025.112266","url":null,"abstract":"<div><div>On February 6, 2023, two major earthquakes with magnitudes <em>M</em><sub><em>w</em></sub> = 7.7 and <em>M</em><sub><em>w</em></sub> = 7.6 struck southeastern Turkiye, causing catastrophic damage and loss of life across 11 provinces, including Malatya. This study focuses on documenting the geotechnical observations and structural damage in Dogansehir, one of the hardest-hit districts not only in Malatya but in the entire affected region. An overview of the -region's tectonic and geological background is presented, followed by an analysis of ground motion data specific to Malatya. A detailed examination of seismic data from stations near Dogansehir was provided to better understand the seismic demands during the earthquakes. The paper then provides insights into the geotechnical conditions, building characteristics, and a damage ratio map of Dogansehir. The influence of local tectonics and geology on the observed damage is analyzed, alongside an evaluation of the seismic performance of masonry and reinforced concrete structures. Dogansehir, located near the epicenters of the Kahramanmaras earthquakes, suffered major structural damage. This was due to the surface rupture occurring near the settlement areas, the establishment of the district centre on the alluvial soil layer and the deficiencies/errors in the building systems. Building settlements on or near active fault zones, as well as on soft soil, leads to serious consequences and should be avoided or require special precautions.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"104 ","pages":"Article 112266"},"PeriodicalIF":6.7,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143570503","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}

引用次数: 0

Influence of nano-silica and r-MgO on rheological properties, 3D printability, and mechanical properties of one-part sodium carbonate-activated slag-based mixes

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering

Pub Date : 2025-03-03 DOI: 10.1016/j.jobe.2025.112245

Büşra Aktürk , Onur Ertuğrul , Ömer Can Özen , Didem Oktay , Tuğrul Yazar

Interest in 3D concrete printing is growing quickly in academia and industry. Alkali-activated materials (AAMs) are a greener alternative to cement but traditional AAMs face challenges with high-viscosity alkaline solutions and energy demands. One-part AAMs, using solid activators and aluminosilicate precursors, present a promising solution. This research investigated the potential producibility of one-part sodium carbonate-activated, slag-based 3D printable mixes. The disadvantages of sodium carbonate activation were mitigated by using reactive MgO (r-MgO), obtained through low-temperature calcination, as a partial substitute for the primary precursor, slag. Additionally, nano-silica was incorporated into the mixes to improve rheological and mechanical properties as well as printability. Several mixes were developed using varying amounts of r-MgO, up to 15 %, and a small amount of nano-silica, 1 % by weight. Rheological properties, including static and dynamic yield stress and viscosity recovery, were evaluated. The printability and buildability of the mixes were experimentally assessed to determine their feasibility for 3D printing. The test results indicated that printable, buildable mixes with proper setting times and sufficient compressive strength can be obtained by substituting slag with r-MgO in specific amounts, namely 10 % and 15 % by weight. While yield stress, compressive strength, printability, and buildability improved with r-MgO substitution, setting time decreased. Furthermore, the inclusion of nano-silica significantly enhanced rheological properties, while mechanical properties showed a slight improvement in 3D-printed samples, which also enabled printable mixes with low r-MgO content (5 %). Moreover, the environmental impact of the produced mixes was found to be much lower than that of Portland-cement-based mixes. In conclusion, one-part sodium carbonate-activated, slag-based mixes present a viable and environmentally friendly alternative for 3D-printable mortar, in case of the inclusion of r-MgO.

{"title":"Influence of nano-silica and r-MgO on rheological properties, 3D printability, and mechanical properties of one-part sodium carbonate-activated slag-based mixes","authors":"Büşra Aktürk , Onur Ertuğrul , Ömer Can Özen , Didem Oktay , Tuğrul Yazar","doi":"10.1016/j.jobe.2025.112245","DOIUrl":"10.1016/j.jobe.2025.112245","url":null,"abstract":"<div><div>Interest in 3D concrete printing is growing quickly in academia and industry. Alkali-activated materials (AAMs) are a greener alternative to cement but traditional AAMs face challenges with high-viscosity alkaline solutions and energy demands. One-part AAMs, using solid activators and aluminosilicate precursors, present a promising solution. This research investigated the potential producibility of one-part sodium carbonate-activated, slag-based 3D printable mixes. The disadvantages of sodium carbonate activation were mitigated by using reactive MgO (r-MgO), obtained through low-temperature calcination, as a partial substitute for the primary precursor, slag. Additionally, nano-silica was incorporated into the mixes to improve rheological and mechanical properties as well as printability. Several mixes were developed using varying amounts of r-MgO, up to 15 %, and a small amount of nano-silica, 1 % by weight. Rheological properties, including static and dynamic yield stress and viscosity recovery, were evaluated. The printability and buildability of the mixes were experimentally assessed to determine their feasibility for 3D printing. The test results indicated that printable, buildable mixes with proper setting times and sufficient compressive strength can be obtained by substituting slag with r-MgO in specific amounts, namely 10 % and 15 % by weight. While yield stress, compressive strength, printability, and buildability improved with r-MgO substitution, setting time decreased. Furthermore, the inclusion of nano-silica significantly enhanced rheological properties, while mechanical properties showed a slight improvement in 3D-printed samples, which also enabled printable mixes with low r-MgO content (5 %). Moreover, the environmental impact of the produced mixes was found to be much lower than that of Portland-cement-based mixes. In conclusion, one-part sodium carbonate-activated, slag-based mixes present a viable and environmentally friendly alternative for 3D-printable mortar, in case of the inclusion of r-MgO.</div></div>","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"104 ","pages":"Article 112245"},"PeriodicalIF":6.7,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143550552","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}

引用次数: 0

Experimental study on rheological properties and 3D printing of simulated lunar soil polymers

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering

Pub Date : 2025-03-03 DOI: 10.1016/j.jobe.2025.112256

Liqing Li , Zhenkun Shi , Lei Wang , Yi Sui , Siyuan Meng

Lunar soil-based polymers, created using lunar soil as a precursor combined with highly automated 3D printing construction methods, hold great potential for lunar base construction. However, technical challenges such as ambiguities in characterizing rheological behavior and difficulties in regulation limit their 3D printing workability. To address these issues, the applicability of the Bingham model, Herschel-Bulkley (H-B) model, and a modified Bingham model to TJ-1 simulated lunar soil-based polymer was investigated by analyzing the fluidity variation. The effects of the solid-liquid ratio, Ca(OH)₂, and Hydroxypropyl Methyl Cellulose ether (HPMC) on the 3D printing performance of the simulated lunar soil-based polymer were explored through one-way tests and standard deviation analysis. The results show that the modified Bingham model more accurately describes the rheological properties of TJ-1 simulated lunar soil-based polymer. HPMC proved to be an effective thixotropic agent for adjusting the 3D printing performance of the polymer. The yield stress and plastic viscosity of the polymer doped with 0.15 % HPMC were 3.577 Pa and 0.733 Pa s, respectively, meeting the requirements for printability. The yield stress and plastic viscosity of the simulated lunar soil polymers ranged from 1.84 to 3.58 Pa and 0.23–0.73 Pa s, respectively. Moreover, the compressive and flexural strengths of the simulated lunar soil polymers were significantly improved by adding Ca(OH)₂. The optimal ratios for 3D-printed simulated lunar soil polymers are a water–cement ratio of 0.30, 10 % NaOH, 8 % Na₂SiO₃, 6 % Ca(OH)₂, and 0.10 % HPMC. Under these conditions, the 28-day compressive strength and flexural strength were 19.5 MPa and 6.9 MPa, respectively, meeting the strength standards of ordinary sintered bricks.The research results could provide a theoretical basis for the subsequent optimization of the simulated lunar soil base polymer mixing ratios for 3D printing.

以月球土壤为前体，结合高度自动化的三维打印制造方法制造出的月球土壤基聚合物，在月球基地建设方面具有巨大潜力。然而，技术上的挑战，如流变行为表征的模糊性和调节上的困难，限制了其 3D 打印的可操作性。为了解决这些问题，研究人员通过分析流动性变化，研究了宾汉模型、赫歇尔-布克雷（H-B）模型和改进的宾汉模型对 TJ-1 模拟月壤基聚合物的适用性。通过单因素试验和标准偏差分析，探讨了固液比、Ca（OH）2 和羟丙基甲基纤维素醚（HPMC）对模拟月壤基聚合物 3D 打印性能的影响。结果表明，改进的宾汉模型能更准确地描述 TJ-1 模拟月壤基聚合物的流变特性。事实证明，HPMC 是调整聚合物 3D 打印性能的有效触变剂。掺杂了 0.15 % HPMC 的聚合物的屈服应力和塑性粘度分别为 3.577 Pa 和 0.733 Pa s，符合打印性能要求。模拟月球土壤聚合物的屈服应力和塑性粘度分别为 1.84 至 3.58 Pa 和 0.23-0.73 Pa s。此外，加入 Ca（OH）2 后，模拟月球土壤聚合物的抗压和抗折强度得到了显著提高。三维打印模拟月球土壤聚合物的最佳配比为水灰比 0.30、10 % NaOH、8 % Na2SiO3、6 % Ca(OH)2 和 0.10 % HPMC。在此条件下，28天的抗压强度和抗折强度分别为19.5兆帕和6.9兆帕，达到了普通烧结砖的强度标准。该研究成果可为后续优化3D打印模拟月壤基质聚合物混合比例提供理论依据。

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引用次数: 0

Influence of fly ash on the long-term performance of low water-to-binder ratio paste containing silica fume in water curing and drying curing regimes

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering

Pub Date : 2025-03-03 DOI: 10.1016/j.jobe.2025.112255

Fangmei Huang , Baochun Chen , Xiancheng Li , Zihao Liu , Wen Xu , Xia Luo , Cong Li

The integration of fly ash into silica fume-containing cement-based material with low water-to-binder ratios (w/b) aims to elevate their overall performance. Nevertheless, the evolution of properties in these materials reinforced with fly ash, and the impact of fly ash on properties, remains elusive. This study delved into the behavior of water uptake and loss, deformation patterns, and mechanical attributes of low w/b paste, subjected to curing in limewater and drying regimes. The cementitious composition of the low w/b paste consists of cement, augmented by 15 % silica fume, and further modified with varying proportions of fly ash. The study also looked into the role of fly ash in paste performance by carrying out comprehensive evaluations of hydration, the resultant hydration product, and the characteristics of cracks that developed. The findings reveal that for low w/b paste, spherical fly ash should be preferred, as under varying curing conditions, the honeycomb-structured fly ash exacerbated water migration, thereby amplifying the deformation in the paste with low w/b containing silica fume. A relatively high dosage of fly ash incorporation was necessary to significantly enhance the hydration degree of cement in low w/b pastes. The effects of fly ash on the compressive strengths of low w/b pastes containing silica fume were relatively minor under various curing conditions but reduced the flexural strengths of the low w/b pastes with silica fume under dry curing conditions.

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引用次数: 0

Evaluation of the effectiveness of electrochemical re-alkalization repair techniques for reinforced concrete structures of historical buildings: A case study

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering

Pub Date : 2025-03-03 DOI: 10.1016/j.jobe.2025.112246

Xiao-dong Wen , Xin-yuan Yao , Jun Xing , Jian Chen

Electrochemical re-alkalization technique is an effective method for non-destructive restoration of carbonized reinforced concrete structures in historic buildings. In this paper, 21 groups of reinforced concrete specimens were designed for re-alkalization tests. The effects of different parameters such as energization time, current density, electrolyte solution type and concentration on the repair effect and safety were analyzed. A safety assessment was also carried out to address the possible problems of alkali aggregate reaction and bond strength degradation that may arise from the current electrochemical 2 technology. The test results show that when the energization time is 14d and the current density is 3A/m², the natural corrosion potential change of rebar after re-alkalization has a larger positive shift, and the bond strength between rebar and concrete is larger and the bond performance is better. On this basis, extend the energization time to 21d, the re-alkalization depth is maximum, the pore liquid phase pH value after re-alkalization is maximum 10.89, the alkaline restoration effect is better, currently, the lowest cementite alkali content within the concrete, and the risk of alkali aggregate reaction is low. This technology can effectively repair the carbonization corrosion of reinforced concrete in ancient buildings without the risk of alkaline aggregate reaction, which provides a reference for the protection of cultural relics.

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引用次数: 0