Pub Date : 2026-02-09DOI: 10.1016/j.jobe.2026.115568
Aron Berhanu Degefa, Woldeamanuel Minwuye Mesfin, Hyeong-Ki Kim, Solmoi Park
This study presents a methodology for durability-based design using machine learning (ML) models to predict chloride resistance and service life in blended concrete. Key ML models—Gaussian Process Regression (GPR), Series Neural Networks (SNN), and ensemble methods—were employed to estimate chloride migration and diffusion coefficients for concrete containing slag, fly ash, and silica fume. GPR and SNN models achieved the highest accuracy across datasets, with each model demonstrating optimal performance in specific chloride exposure conditions. The ML models’ predictions aligned conservatively with experimental data and fib Model Code 2010 values, reinforcing their reliability. Probabilistic simulations revealed that ML-predicted migration coefficients significantly influence service life estimates, particularly for slag and fly ash binders. The findings suggest that pretrained ML models can support early-stage durability assessments, supplementing traditional design methods when experimental data are limited.
{"title":"Machine Learning-Driven Prediction of Chloride Resistance and Service Life Estimation in Blended Cement Concrete","authors":"Aron Berhanu Degefa, Woldeamanuel Minwuye Mesfin, Hyeong-Ki Kim, Solmoi Park","doi":"10.1016/j.jobe.2026.115568","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115568","url":null,"abstract":"This study presents a methodology for durability-based design using machine learning (ML) models to predict chloride resistance and service life in blended concrete. Key ML models—Gaussian Process Regression (GPR), Series Neural Networks (SNN), and ensemble methods—were employed to estimate chloride migration and diffusion coefficients for concrete containing slag, fly ash, and silica fume. GPR and SNN models achieved the highest accuracy across datasets, with each model demonstrating optimal performance in specific chloride exposure conditions. The ML models’ predictions aligned conservatively with experimental data and <ce:italic>fib</ce:italic> Model Code 2010 values, reinforcing their reliability. Probabilistic simulations revealed that ML-predicted migration coefficients significantly influence service life estimates, particularly for slag and fly ash binders. The findings suggest that pretrained ML models can support early-stage durability assessments, supplementing traditional design methods when experimental data are limited.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"7 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146564","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 : 2026-02-09DOI: 10.1016/j.jobe.2026.115497
Salah Almazmumi, Carlos Jimenez-Bescos, John S. Owen, John Kaiser Calautit
Single-sided ventilation (SSV) in multi-storey buildings often suffers from limited flow penetration, strong directional dependence, and floor-to-floor imbalance. This study investigates a façade-integrated Wall Windcatcher (WWC) system designed to overcome these limitations by combining a low-level supply inlet and a high-level exhaust outlet on the same façade, connected by an external vertical duct. A computational fluid dynamics (CFD) framework was first validated against atmospheric boundary layer wind-tunnel measurements using a baseline WWC geometry, which then served as the reference model for a systematic parametric analysis of geometric modifications and contextual factors based on a steady-state RANS (k–ε RNG) approach. Design variants were tested across wind angles from 0° to 180° to capture windward, oblique, perpendicular, and leeward exposures. For the k–ε RNG model, agreement in pressure coefficients (Cp) for WWC cases yielded MAPE = 5.6% (0° wind angle), 4.6% (45°), and 6.8% (90°), respectively, confirming the accuracy of the CFD framework for subsequent analysis. Three design parameters were tested individually and in combination: (i) transitions before each outlet, (ii) enlarged outlet size, and (iii) a thin inlet plane. Transitions reduced junction losses and improved vertical continuity, enlarged outlets strengthened upper-storey extraction but could suppress ground-floor intake at high obliquity, and the inlet plane provided the largest single improvement under oblique winds. The fully integrated design (COC2: inlet plane + transitions + enlarged outlet) achieved the highest and most uniform velocities, with up to 2–3× higher performance than the baseline and measurable improvements even under leeward winds. Increasing building height (to four and five storeys) enhanced mid- and upper-floor ventilation without significantly penalising lower levels. Urban-canyon simulations showed that wider street-to-building ratios improved windward and side-zone performance, while leeward zones remained limited by wake shielding. The results demonstrate that a retrofit-focused WWC can outperform SSV when inlet capture (inlet plane), duct continuity (transitions), and outlet discharge are optimised together. The findings provide practical guidance for passive ventilation design, and the development of modular façade retrofit systems for multi-storey buildings.
{"title":"Parametric Evaluation of a Façade-Integrated Natural Ventilation System for Multi-Storey Buildings","authors":"Salah Almazmumi, Carlos Jimenez-Bescos, John S. Owen, John Kaiser Calautit","doi":"10.1016/j.jobe.2026.115497","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115497","url":null,"abstract":"Single-sided ventilation (SSV) in multi-storey buildings often suffers from limited flow penetration, strong directional dependence, and floor-to-floor imbalance. This study investigates a façade-integrated Wall Windcatcher (WWC) system designed to overcome these limitations by combining a low-level supply inlet and a high-level exhaust outlet on the same façade, connected by an external vertical duct. A computational fluid dynamics (CFD) framework was first validated against atmospheric boundary layer wind-tunnel measurements using a baseline WWC geometry, which then served as the reference model for a systematic parametric analysis of geometric modifications and contextual factors based on a steady-state RANS (k–ε RNG) approach. Design variants were tested across wind angles from 0° to 180° to capture windward, oblique, perpendicular, and leeward exposures. For the k–ε RNG model, agreement in pressure coefficients (C<ce:inf loc=\"post\">p</ce:inf>) for WWC cases yielded MAPE = 5.6% (0° wind angle), 4.6% (45°), and 6.8% (90°), respectively, confirming the accuracy of the CFD framework for subsequent analysis. Three design parameters were tested individually and in combination: (i) transitions before each outlet, (ii) enlarged outlet size, and (iii) a thin inlet plane. Transitions reduced junction losses and improved vertical continuity, enlarged outlets strengthened upper-storey extraction but could suppress ground-floor intake at high obliquity, and the inlet plane provided the largest single improvement under oblique winds. The fully integrated design (COC2: inlet plane + transitions + enlarged outlet) achieved the highest and most uniform velocities, with up to 2–3× higher performance than the baseline and measurable improvements even under leeward winds. Increasing building height (to four and five storeys) enhanced mid- and upper-floor ventilation without significantly penalising lower levels. Urban-canyon simulations showed that wider street-to-building ratios improved windward and side-zone performance, while leeward zones remained limited by wake shielding. The results demonstrate that a retrofit-focused WWC can outperform SSV when inlet capture (inlet plane), duct continuity (transitions), and outlet discharge are optimised together. The findings provide practical guidance for passive ventilation design, and the development of modular façade retrofit systems for multi-storey buildings.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"51 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146707","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 : 2026-02-09DOI: 10.1016/j.jobe.2026.115533
Peng Wang, Longbin Yang, Qingxuan Shi, Qiuwei Wang, Chong Rong
This study proposes a novel two-way slab system integrating stay-in-place ultra-high-performance concrete (UHPC) formwork with a cast-in-place reinforced concrete (RC) layer to enhance mechanical performance and construction efficiency through material and structural optimization. Flexural tests were conducted to systematically investigate the effects of UHPC formwork thickness, reinforcement ratio, and interface treatment on the failure modes, load-bearing capacity, and deformation behavior of the slabs. A complementary numerical model was developed and validated to extend the parametric analysis. The experimental results demonstrated that the ribbed interface treatment significantly enhanced the composite action and effectively suppressed interfacial slip. Compared to specimens with bubble-film-embossing and roughened interfaces, the ribbed ones exhibited 12% and 20% higher peak loads, accompanied by 26% and 24% reductions in peak deflection, respectively. An increase in the reinforcement ratio from 0.28% to 0.61% resulted in a 27% increase in both yield and peak loads, but also led to a 60% rise in peak deflection. However, this increase compromised ductility, as indicated by a ductility factor of 5.56 at the reinforcement ratio of 0.61%. Increasing the UHPC formwork thickness from 10 mm to 15 mm enhanced the yield and peak loads by 10% and 8%, respectively, and reduced the peak deflection by 26%. Numerical simulations further indicated that increasing the normal concrete (NC) strength from 30 MPa to 50 MPa enhanced the load-bearing capacity by 16%. Similarly, increasing the UHPC formwork thickness from 10 mm to 40 mm resulted in a 31.37% increase in capacity. Based on the plastic hinge line theory and the principle of virtual work, a method for predicting the ultimate load-bearing capacity under different failure modes was proposed. The predicted values showed a maximum deviation of 15% from the experimental results, with a mean calculated-to-experimental ratio of 0.95, confirming the accuracy of the proposed method.
{"title":"Flexural Behavior and Load-Bearing Capacity of UHPC Stay-in-Place Formwork-RC Two-Way Slabs","authors":"Peng Wang, Longbin Yang, Qingxuan Shi, Qiuwei Wang, Chong Rong","doi":"10.1016/j.jobe.2026.115533","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115533","url":null,"abstract":"This study proposes a novel two-way slab system integrating stay-in-place ultra-high-performance concrete (UHPC) formwork with a cast-in-place reinforced concrete (RC) layer to enhance mechanical performance and construction efficiency through material and structural optimization. Flexural tests were conducted to systematically investigate the effects of UHPC formwork thickness, reinforcement ratio, and interface treatment on the failure modes, load-bearing capacity, and deformation behavior of the slabs. A complementary numerical model was developed and validated to extend the parametric analysis. The experimental results demonstrated that the ribbed interface treatment significantly enhanced the composite action and effectively suppressed interfacial slip. Compared to specimens with bubble-film-embossing and roughened interfaces, the ribbed ones exhibited 12% and 20% higher peak loads, accompanied by 26% and 24% reductions in peak deflection, respectively. An increase in the reinforcement ratio from 0.28% to 0.61% resulted in a 27% increase in both yield and peak loads, but also led to a 60% rise in peak deflection. However, this increase compromised ductility, as indicated by a ductility factor of 5.56 at the reinforcement ratio of 0.61%. Increasing the UHPC formwork thickness from 10 mm to 15 mm enhanced the yield and peak loads by 10% and 8%, respectively, and reduced the peak deflection by 26%. Numerical simulations further indicated that increasing the normal concrete (NC) strength from 30 MPa to 50 MPa enhanced the load-bearing capacity by 16%. Similarly, increasing the UHPC formwork thickness from 10 mm to 40 mm resulted in a 31.37% increase in capacity. Based on the plastic hinge line theory and the principle of virtual work, a method for predicting the ultimate load-bearing capacity under different failure modes was proposed. The predicted values showed a maximum deviation of 15% from the experimental results, with a mean calculated-to-experimental ratio of 0.95, confirming the accuracy of the proposed method.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"108 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146604","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}
Improving the thermal efficiency of building envelopes while maintaining mechanical integrity remains a significant challenge in sustainable construction. Conventional insulation mortars often fail to achieve simultaneous optimization of thermal conductivity, moisture resistance, and strength. This study addresses this gap by developing aerogel-perlite-cement (ACM) composite insulation mortars designed through particle packing optimization and systematically evaluating their thermal, mechanical, and hygric performance, as well as their impact on building energy consumption. Mortars with varying aggregate gradations were designed using the modified Andreasen & Andersen model (distribution moduli q=0.2, 0.3), and a silica aerogel slurry was incorporated into expanded perlite carriers. Compared with conventional cement mortars (CM), optimized ACM samples achieved a 19% reduction in bulk density, an 18% improvement in water resistance, and reduced thermal conductivity to 0.059 W·m-1·K-1, while maintaining acceptable compressive strength (1.49 MPa). The experimental thermal conductivity results were further interpreted using effective medium theory (EMT) in combination with finite-element simulations, which together elucidate the influence of aggregate gradation, interfacial effects, and structural heterogeneity on heat transfer behavior in aerogel-modified mortars. EnergyPlus simulations of a six-story residential building demonstrated that applying a 100 mm ACM insulation layer can reduce annual HVAC energy consumption by 50.9% in cold regions and 33.8% in mixed climates, providing practical insights into climate-adaptive design.
{"title":"Performance-Driven Design of Aerogel-Perlite Cement Mortars: Particle Packing Optimization and Building Energy Assessment","authors":"Shengjie Yao, Yuming Duan, Weiwang Chen, Jiahui Chen, Huanlin Zhang, Longhui Peng, Xiaoxu Wu, Zhi Li","doi":"10.1016/j.jobe.2026.115567","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115567","url":null,"abstract":"Improving the thermal efficiency of building envelopes while maintaining mechanical integrity remains a significant challenge in sustainable construction. Conventional insulation mortars often fail to achieve simultaneous optimization of thermal conductivity, moisture resistance, and strength. This study addresses this gap by developing aerogel-perlite-cement (ACM) composite insulation mortars designed through particle packing optimization and systematically evaluating their thermal, mechanical, and hygric performance, as well as their impact on building energy consumption. Mortars with varying aggregate gradations were designed using the modified Andreasen & Andersen model (distribution moduli <ce:italic>q=0.2, 0.3</ce:italic>), and a silica aerogel slurry was incorporated into expanded perlite carriers. Compared with conventional cement mortars (CM), optimized ACM samples achieved a 19% reduction in bulk density, an 18% improvement in water resistance, and reduced thermal conductivity to 0.059 W·m<ce:sup loc=\"post\">-1</ce:sup>·K<ce:sup loc=\"post\">-1</ce:sup>, while maintaining acceptable compressive strength (1.49 MPa). The experimental thermal conductivity results were further interpreted using effective medium theory (EMT) in combination with finite-element simulations, which together elucidate the influence of aggregate gradation, interfacial effects, and structural heterogeneity on heat transfer behavior in aerogel-modified mortars. EnergyPlus simulations of a six-story residential building demonstrated that applying a 100 mm ACM insulation layer can reduce annual HVAC energy consumption by 50.9% in cold regions and 33.8% in mixed climates, providing practical insights into climate-adaptive design.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"105 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146681","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 : 2026-02-09DOI: 10.1016/j.jobe.2026.115592
Tae Yong Shin, Seongho Han, Ryong You, Yubin Jun, Jae Hong Kim
Alkali-activated materials have emerged as promising low-carbon alternatives to ordinary Portland cement-based binders; however, their practical application is strictly limited by rapid setting and poor workability. To address these challenges, this study proposes an evaluation methodology combining setting time measurement, cloud point tests for chemical stability, and wide-range rheological analysis. While conventional superplasticizers like polycarboxylate ether (PCE) proved unstable in high-alkaline environments, cloud point tests revealed that polynaphthalene sulfonate (PNS) and butyl acrylate (BA) exhibited superior chemical stability. Notably, BA was identified as a novel and effective dispersant in 3.5 M KOH-activated systems, reducing yield stress of fresh mortar by 33% when combined with an anti-foaming agent. In terms of retardation, 0.06% sodium gluconate (SG) successfully extended the initial setting time to over 5 hours. Furthermore, rheological modeling revealed that replacing 10% of ground granulated blast-furnace slag with fly ash not only reduced viscosity but also enhanced the 28-day compressive strength to 45.0 MPa, surpassing the control sample (43.7 MPa) due to improved particle packing. These findings offer practical guidelines for enhancing the workability of alkali-activated slag mortars through the use of chemically stable admixtures and optimized mineral substitution.
碱活化材料已经成为普通硅酸盐水泥基粘合剂的有前途的低碳替代品；但由于成型速度快、可加工性差，严格限制了其实际应用。为了应对这些挑战，本研究提出了一种结合凝结时间测量、化学稳定性浊点测试和大范围流变分析的评估方法。虽然聚羧酸酯醚（PCE）等传统高效减水剂在高碱性环境中不稳定，但云点测试表明，聚萘磺酸盐（PNS）和丙烯酸丁酯（BA）表现出优异的化学稳定性。值得注意的是，BA在3.5 M koh活化体系中被认为是一种新型有效的分散剂，当与消泡剂结合使用时，可将新鲜砂浆的屈服应力降低33%。在缓凝方面，0.06%的葡萄糖酸钠（SG）成功地将初凝时间延长至5小时以上。此外，流变学模型表明，用粉煤灰代替10%的磨粒高炉渣不仅降低了粘度，而且由于颗粒填料的改善，28天抗压强度提高到45.0 MPa，超过了对照样品（43.7 MPa）。这些发现为通过使用化学稳定的外加剂和优化的矿物替代来提高碱活性矿渣砂浆的和易性提供了实用指南。
{"title":"Rheological Modification of Alkali-Activated Slag Mortar: Roles of Sodium Gluconate Retarder and Dispersants","authors":"Tae Yong Shin, Seongho Han, Ryong You, Yubin Jun, Jae Hong Kim","doi":"10.1016/j.jobe.2026.115592","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115592","url":null,"abstract":"Alkali-activated materials have emerged as promising low-carbon alternatives to ordinary Portland cement-based binders; however, their practical application is strictly limited by rapid setting and poor workability. To address these challenges, this study proposes an evaluation methodology combining setting time measurement, cloud point tests for chemical stability, and wide-range rheological analysis. While conventional superplasticizers like polycarboxylate ether (PCE) proved unstable in high-alkaline environments, cloud point tests revealed that polynaphthalene sulfonate (PNS) and butyl acrylate (BA) exhibited superior chemical stability. Notably, BA was identified as a novel and effective dispersant in 3.5 M KOH-activated systems, reducing yield stress of fresh mortar by 33% when combined with an anti-foaming agent. In terms of retardation, 0.06% sodium gluconate (SG) successfully extended the initial setting time to over 5 hours. Furthermore, rheological modeling revealed that replacing 10% of ground granulated blast-furnace slag with fly ash not only reduced viscosity but also enhanced the 28-day compressive strength to 45.0 MPa, surpassing the control sample (43.7 MPa) due to improved particle packing. These findings offer practical guidelines for enhancing the workability of alkali-activated slag mortars through the use of chemically stable admixtures and optimized mineral substitution.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"46 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146563","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 : 2026-02-09DOI: 10.1016/j.jobe.2026.115581
Jian Yang, Jieqiong Wu, Liu Jin, Xiuli Du
To investigate the bond performance between steel/BFRP bar and concrete under low-temperature freeze-thaw and chloride attack, 72 specimens were subjected to the bond test, and a refined 3D bond model was developed, which explicitly incorporated bar surface geometry and freeze-thaw induced concrete deterioration. The results show that: (1) For thick concrete covers (≥70 mm), the failure mode is mainly determined by bar diameter, not freeze-thaw cycles. However, for BFRP specimens with thin covers (≤40 mm), the failure mode changes from pull-out to splitting failure after 200 cycles. (2) Bond strength decreases with increasing freeze-thaw cycles and bar diameter, but increases with concrete cover thickness. Steel bar specimens exhibit more severe bond degradation than BFRP bar specimens. (3) Peak slip decreases with freeze-thaw cycles but increases with bar diameter and cover thickness. (4) Increasing concrete cover thickness significantly mitigates the degradation effects of freeze-thaw on both bond strength and peak slip. Based on the experimental and simulated results, a bond stress-slip model incorporating the effects of low-temperature freeze-thaw cycles and cover-to-diameter ratio is proposed and validated.
{"title":"Study on the bond performance between steel/BFRP bar and concrete considering diameter, concrete cover thickness and low-temperature freeze-thaw","authors":"Jian Yang, Jieqiong Wu, Liu Jin, Xiuli Du","doi":"10.1016/j.jobe.2026.115581","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115581","url":null,"abstract":"To investigate the bond performance between steel/BFRP bar and concrete under low-temperature freeze-thaw and chloride attack, 72 specimens were subjected to the bond test, and a refined 3D bond model was developed, which explicitly incorporated bar surface geometry and freeze-thaw induced concrete deterioration. The results show that: (1) For thick concrete covers (≥70 mm), the failure mode is mainly determined by bar diameter, not freeze-thaw cycles. However, for BFRP specimens with thin covers (≤40 mm), the failure mode changes from pull-out to splitting failure after 200 cycles. (2) Bond strength decreases with increasing freeze-thaw cycles and bar diameter, but increases with concrete cover thickness. Steel bar specimens exhibit more severe bond degradation than BFRP bar specimens. (3) Peak slip decreases with freeze-thaw cycles but increases with bar diameter and cover thickness. (4) Increasing concrete cover thickness significantly mitigates the degradation effects of freeze-thaw on both bond strength and peak slip. Based on the experimental and simulated results, a bond stress-slip model incorporating the effects of low-temperature freeze-thaw cycles and cover-to-diameter ratio is proposed and validated.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"30 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146602","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 : 2026-02-09DOI: 10.1016/j.jobe.2026.115587
João Victor da Cunha-Oliveira, Frankslale Fabian Diniz de Andrade Meira, Leila Soares Viegas Barreto Chagas, André Luiz Fiquene de Brito, Romualdo Rodrigues Menezes, Gelmires de Araújo Neves
This study presents a novel, low-carbon alternative for sewage sludge valorization by investigating low-temperature dehydration treatment (160-240 °C) to produce a particulate material (filler) for ultra-high performance concrete (UHPC), replacing silica fume (2-8%). The treatment at 240 °C yielded a filler (DS240) with improved physicochemical characteristics, including higher specific gravity (2.57 g/cm3), lower loss on ignition (20.7%), and higher BET surface area (9.43 m2/g), alongside the reduction of O–H and N–H groups and the formation of aliphatic structures. Simultaneous increases of 7.6% in workability and 9.7% in 28-day compressive strength were observed in UHPC-6%, while alkalinity remained constant across all compositions. Particle packing analysis showed that DS240 favored the mechanical performance improvement through its micro-filling effect. Furthermore, TCLP leaching tests confirmed that the UHPC-8% composite fully complied with the regulatory limits for the evaluated heavy metals (Cd, Pb, As and Se). Microstructurally, DS240 modified the hydration kinetics, delaying precipitation of C-S-H and portlandite and induced the crystallization of AFt and long-chain Q4 polymerized silicates. Moreover, the filler favored the formation of C-Ᾱ-S-H phases through the dissolution of aluminates. These effects resulted in strengths exceeding 200 MPa in all compositions. Additionally, the assessment through the Empathetic Added Sustainability Index (EASI) quantified a 9.5% gain in the overall sustainability of UHPC-6% compared to UHPC-0%. Therefore, low-temperature dehydration converts sewage sludge into a UHPC filler that improves performance and sustainability with regulatory immobilization (TCLP) of metals, validating its technical and environmental potential.
本研究通过研究低温脱水处理（160-240°C）来生产一种用于超高性能混凝土（UHPC）的颗粒材料（填料），取代硅灰（2-8%），提出了一种新的低碳污水污泥固化替代方案。在240°C下处理得到的填料（DS240）具有改善的物理化学特性，包括更高的比重（2.57 g/cm3），更低的着火损失（20.7%），更高的BET表面积（9.43 m2/g），以及O-H和N-H基团的减少和脂肪族结构的形成。在UHPC-6%中，可加工性同时增加7.6%，28天抗压强度同时增加9.7%，而所有成分的碱度保持不变。颗粒充填分析表明，DS240的微填充效应有利于力学性能的提高。此外，TCLP浸出试验证实，UHPC-8%复合材料完全符合评估重金属（Cd, Pb， As和Se）的法规限值。微观结构上，DS240改变了水化动力学，延缓了C-S-H和硅酸盐的沉淀，诱导了AFt和长链Q4聚合硅酸盐的结晶。此外，填料有利于通过铝酸盐的溶解形成C-Ᾱ- s - h相。这些影响导致所有成分的强度都超过200mpa。此外，通过移情附加可持续性指数（EASI）进行的评估量化了uhpc的总体可持续性增长9.5% -6%，而uhpc为0%。因此，低温脱水将污水污泥转化为UHPC填料，通过金属的调节固定化（TCLP）提高了性能和可持续性，验证了其技术和环境潜力。
{"title":"Low-temperature treated sewage sludge as filler for ultra-high performance concrete application","authors":"João Victor da Cunha-Oliveira, Frankslale Fabian Diniz de Andrade Meira, Leila Soares Viegas Barreto Chagas, André Luiz Fiquene de Brito, Romualdo Rodrigues Menezes, Gelmires de Araújo Neves","doi":"10.1016/j.jobe.2026.115587","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115587","url":null,"abstract":"This study presents a novel, low-carbon alternative for sewage sludge valorization by investigating low-temperature dehydration treatment (160-240 °C) to produce a particulate material (filler) for ultra-high performance concrete (UHPC), replacing silica fume (2-8%). The treatment at 240 °C yielded a filler (DS240) with improved physicochemical characteristics, including higher specific gravity (2.57 g/cm<ce:sup loc=\"post\">3</ce:sup>), lower loss on ignition (20.7%), and higher BET surface area (9.43 m<ce:sup loc=\"post\">2</ce:sup>/g), alongside the reduction of O–H and N–H groups and the formation of aliphatic structures. Simultaneous increases of 7.6% in workability and 9.7% in 28-day compressive strength were observed in UHPC-6%, while alkalinity remained constant across all compositions. Particle packing analysis showed that DS240 favored the mechanical performance improvement through its micro-filling effect. Furthermore, TCLP leaching tests confirmed that the UHPC-8% composite fully complied with the regulatory limits for the evaluated heavy metals (Cd, Pb, As and Se). Microstructurally, DS240 modified the hydration kinetics, delaying precipitation of C-S-H and portlandite and induced the crystallization of AFt and long-chain Q<ce:inf loc=\"post\">4</ce:inf> polymerized silicates. Moreover, the filler favored the formation of C-Ᾱ-S-H phases through the dissolution of aluminates. These effects resulted in strengths exceeding 200 MPa in all compositions. Additionally, the assessment through the Empathetic Added Sustainability Index (EASI) quantified a 9.5% gain in the overall sustainability of UHPC-6% compared to UHPC-0%. Therefore, low-temperature dehydration converts sewage sludge into a UHPC filler that improves performance and sustainability with regulatory immobilization (TCLP) of metals, validating its technical and environmental potential.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"33 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146600","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 : 2026-02-09DOI: 10.1016/j.jobe.2026.115546
Cheng Hu, Xujian Lin, Xin Li, Haosheng Jiang, Tao Ji
Magnesium silicon potassium phosphate cement (MgO-K2HPO4-SiO2, MSPPC) is a new high-performance magnesium-based cementitious material distinguished from traditional magnesium phosphate cement (MPC). Compared with MPC, MSPPC exhibits superior mechanical properties and broader application prospects; however, its strength degradation under long-term water exposure limits its durability in rapid-repair and emergency construction projects. To improve its water resistance, this study introduces montmorillonite (Mt), which possesses excellent adsorption capacity, cation-exchange ability, and dispersion performance, as a synergistic modifier on the basis of 10% slag incorporation. The effects of different Mt contents (0.25%, 0.50%, 0.75%, and 1.00%) on the water-curing performance of MSPPC are systematically investigated. The pore structure evolution and water-stability mechanisms of hydration products are analyzed through multiple micro-characterization techniques, including XRD, SEM-EDS, MIP, and TG-DSC. The results indicate that an appropriate Mt content effectively enhances the structural stability and strength retention of MSPPC in humid environments. When the Mt content reaches 1.00%, the 90 d compressive strength retention ratio reaches 92.69%, although the absolute compressive strength decreases slightly. When the Mt content is 0.50%, the total porosity is the lowest (5.72%), and the pore size distribution becomes significantly refined, contributing to the formation of a dense matrix. Microstructural analyses reveal that montmorillonite optimizes the particle packing, promotes the formation and recrystallization of MKP and related hydration products, and constructs an interwoven spatial network of crystalline and gel phases, thereby simultaneously enhancing pore refinement and hydration-product stability. This study elucidates the synergistic mechanism by which montmorillonite drives microstructural evolution and improves water resistance in MSPPC, providing theoretical support and technical references for the design and engineering application of highly water-resistant magnesium-based cementitious materials.
{"title":"Mechanism of Microstructural Evolution and Water-Resistance Improvement Driven by Montmorillonite in MgO-K2HPO4-SiO2 Cement Systems","authors":"Cheng Hu, Xujian Lin, Xin Li, Haosheng Jiang, Tao Ji","doi":"10.1016/j.jobe.2026.115546","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115546","url":null,"abstract":"Magnesium silicon potassium phosphate cement (MgO-K<ce:inf loc=\"post\">2</ce:inf>HPO<ce:inf loc=\"post\">4</ce:inf>-SiO<ce:inf loc=\"post\">2</ce:inf>, MSPPC) is a new high-performance magnesium-based cementitious material distinguished from traditional magnesium phosphate cement (MPC). Compared with MPC, MSPPC exhibits superior mechanical properties and broader application prospects; however, its strength degradation under long-term water exposure limits its durability in rapid-repair and emergency construction projects. To improve its water resistance, this study introduces montmorillonite (Mt), which possesses excellent adsorption capacity, cation-exchange ability, and dispersion performance, as a synergistic modifier on the basis of 10% slag incorporation. The effects of different Mt contents (0.25%, 0.50%, 0.75%, and 1.00%) on the water-curing performance of MSPPC are systematically investigated. The pore structure evolution and water-stability mechanisms of hydration products are analyzed through multiple micro-characterization techniques, including XRD, SEM-EDS, MIP, and TG-DSC. The results indicate that an appropriate Mt content effectively enhances the structural stability and strength retention of MSPPC in humid environments. When the Mt content reaches 1.00%, the 90 d compressive strength retention ratio reaches 92.69%, although the absolute compressive strength decreases slightly. When the Mt content is 0.50%, the total porosity is the lowest (5.72%), and the pore size distribution becomes significantly refined, contributing to the formation of a dense matrix. Microstructural analyses reveal that montmorillonite optimizes the particle packing, promotes the formation and recrystallization of MKP and related hydration products, and constructs an interwoven spatial network of crystalline and gel phases, thereby simultaneously enhancing pore refinement and hydration-product stability. This study elucidates the synergistic mechanism by which montmorillonite drives microstructural evolution and improves water resistance in MSPPC, providing theoretical support and technical references for the design and engineering application of highly water-resistant magnesium-based cementitious materials.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"93 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146603","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}
This study systematically investigates the reaction kinetics, phase assemblage, and microstructural evolution of alkali-activated magnesium slag and steel slag to address the challenges associated with their valorization due to distinct reactivity. The results reveal that intrinsic compositional differences govern their reaction pathways. The steel slag-based system exhibits high reactivity, forming a complex network of C-A-S-H, layered double hydroxides (LDH), strätlingite, and hydrogarnet. Alkalinity plays a critical role in phase selection. Lower alkalinity favors LDH and hydrogarnet, whereas higher alkalinity promotes strätlingite and rapidly develops a dense, high-strength matrix, reaching a 28-day compressive strength of 21.8 MPa. In contrast, the magnesium slag-based system requires higher alkalinity to form C-A-S-H and M-S-H gels due to its content of stable γ-C2S and periclase. However, high alkalinity triggers expansive hydration of periclase, impairing network integrity and limiting strength gain, and finally resulting in a lower 28-day strength of 8.0 MPa. While both binders effectively immobilize heavy metals, the steel slag system achieves a superior balance of mechanical performance and eco-efficiency at lower alkali dosages. Conversely, the high activator dosage required for magnesium slag is less cost-effective due to diminishing performance returns. This work clarifies the mechanistic divergence between these metallurgical wastes, offering essential guidance for designing sustainable, waste-based binders tailored to specific slag characteristics.
{"title":"Alkali-activated magnesium slag and steel slag materials: Insights into reaction behavior, microstructure evolution, and performance development","authors":"Yumei Nong, MiaoMiao Zhu, Ruoxin Zhai, Mingming Zhu, Yutao Guo, Ruiquan Jia, Jianwei Sun, Zihan Zhou, Shiyu Zhuang","doi":"10.1016/j.jobe.2026.115393","DOIUrl":"https://doi.org/10.1016/j.jobe.2026.115393","url":null,"abstract":"This study systematically investigates the reaction kinetics, phase assemblage, and microstructural evolution of alkali-activated magnesium slag and steel slag to address the challenges associated with their valorization due to distinct reactivity. The results reveal that intrinsic compositional differences govern their reaction pathways. The steel slag-based system exhibits high reactivity, forming a complex network of C-A-S-H, layered double hydroxides (LDH), strätlingite, and hydrogarnet. Alkalinity plays a critical role in phase selection. Lower alkalinity favors LDH and hydrogarnet, whereas higher alkalinity promotes strätlingite and rapidly develops a dense, high-strength matrix, reaching a 28-day compressive strength of 21.8 MPa. In contrast, the magnesium slag-based system requires higher alkalinity to form C-A-S-H and M-S-H gels due to its content of stable γ-C<ce:inf loc=\"post\">2</ce:inf>S and periclase. However, high alkalinity triggers expansive hydration of periclase, impairing network integrity and limiting strength gain, and finally resulting in a lower 28-day strength of 8.0 MPa. While both binders effectively immobilize heavy metals, the steel slag system achieves a superior balance of mechanical performance and eco-efficiency at lower alkali dosages. Conversely, the high activator dosage required for magnesium slag is less cost-effective due to diminishing performance returns. This work clarifies the mechanistic divergence between these metallurgical wastes, offering essential guidance for designing sustainable, waste-based binders tailored to specific slag characteristics.","PeriodicalId":15064,"journal":{"name":"Journal of building engineering","volume":"2 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146683","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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