通讯机构：
[Li, C ] W;Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.
关键词：
Rock mechanic;Fractured rock mass;Prestressed bolt;CT scan;F-T cycle
摘要：
The freeze-thaw (F-T) damage characteristics of anchored fractured rock masses are different from those of fractured rock masses without bolts. To explore the F-T damage location and characterize zonal damage of anchored rock masses, two stages of F-T cycle tests were conducted for the samples with no bolt, 45 degrees bolt and 90 degrees bolt respectively. CT scan tests were performed before and after F-T cycling. Visual damage was qualitatively evaluated through 3D image reconstruction of CT data. The zonal damage characteristics of the samples were quantitatively analyzed using 2-d CT slices, areal porosities, and damage variables of each slice. The results show that the F-T cycles can cause damage in the rock zone, propagation zone, and anchor zone. The damage to samples with a bolt was relatively small, and the damage to the 90 degrees anchor samples was less severe than that to 45 degrees anchor samples. Compared with the samples with no bolts, some of the damage in the propagation zone of the samples with a bolt was transferred to the anchor zone through the bolt, which led to the deterioration of anchoring performance of the bolt. It is necessary to pay attention to the effective reinforcement range within a rock mass reinforced by bolting, and the rock mass outside the reinforcement range is more prone to crack propagation due to the increased frost heaving caused by prestress. The results provide a reference value for the reasonable design of anchorage engineering works in cold area.
摘要：
Arabica coffee, as one of the world's three native coffee species, requires rational planning for its growing areas to ensure ecological and sustainable agricultural development. This study aims to establish a decision-making framework using Geographic Information Systems (GIS) and Multi-Criteria Decision-Making (MCDM), with a focus on assessing the habitat suitability of Arabica coffee in Yunnan Province, China. The impacts of climate, topography, soil, and socio-economic factors were considered by selecting 13 criteria through correlation analysis. Indicator weights were determined using the Best-Worst Method (BWM), while weighted processing was conducted using the Base-Criterion Method (BCM). Sensitivity analysis was performed to verify the accuracy and stability of the model. Additionally, several decision models were evaluated to investigate regionalizing Arabica coffee habitats in Yunnan. The results highlighted that minimum temperature during the coldest month is crucial for evaluation purposes. The BWM-GIS model identified suitable areas comprising 13.55% of the total area as most suitable, 27.46% as suitable, and 59.00% as unsuitable, whereas corresponding values for the BCM-GIS model were 9.97%, 30.43%, and 59.59%. Despite employing different decision-making methods, both models yielded similar and consistent results. The suitable areas mainly encompass Dehong, Pu'er, Lincang, Xishuangbanna, Baoshan, southern Chuxiong, eastern Honghe, southern Yuxi, and parts of Wenshan. BWM-GIS achieved an area under curve (AUC) value of 0.891, while BCM-GIS obtained an AUC value of 0.890, indicating the stability and reliability of the models. Among them, the evaluation process of BCM-GIS was simpler and more realistic. Therefore, it has high feasibility and practical value in practical application. The findings from this study provide a significant scientific foundation for optimizing Yunnan Province.
通讯机构：
[Yang, X ] Y;Yangtze Univ, Sch Urban Construct, Jingzhou 434023, Peoples R China.
关键词：
Steel-UHPC composite structures;Stud connectors;Machine learning;Load-slip curve prediction;Push-out test
摘要：
Machine learning techniques have demonstrated significant potential in predicting the shear mechanical performance of stud connectors. However, predicting the load-slip curves of stud connectors in steel-ultrahigh-performance concrete (UHPC) composite structures remains a challenge. While some empirical models have been developed to describe the load-slip behavior of stud connectors, most are fitted to limited databases, leading to inadequate generalizability. This study presents a series of push-out tests on stud connectors encased in steel-UHPC composite structures, along with a comprehensive analysis of the load-slip curve characteristics derived from the experimental results. Subsequently, eight machine learning models were trained and tested using a database comprising 289 instances from push-out tests. Fourteen key factors were selected as input parameters, and three characteristic values including shear strength, initial shear stiffness, and peak slip were chosen as output parameters. The results indicated that the Extreme Gradient Boosting (XGBoost) model exhibited excellent performance in predicting shear strength and peak slip, with corresponding R² values of 0.988 and 0.814, respectively, while the Categorical Boosting (CatBoost) model performed best in predicting initial shear stiffness with an R² value of 0.867. Feature importance analysis using the Shapley Additive Explanations (SHAP) method highlighted that stud diameter was a critical factor affecting shear strength and initial shear stiffness, while stud height was a critical factor influencing the peak slip. Finally, based on the predicted characteristic values, an effective model was established for predicting the load-slip curve of stud connectors in steel-UHPC composite structures, which was validated to have good accuracy and applicability via the test results.
Machine learning techniques have demonstrated significant potential in predicting the shear mechanical performance of stud connectors. However, predicting the load-slip curves of stud connectors in steel-ultrahigh-performance concrete (UHPC) composite structures remains a challenge. While some empirical models have been developed to describe the load-slip behavior of stud connectors, most are fitted to limited databases, leading to inadequate generalizability. This study presents a series of push-out tests on stud connectors encased in steel-UHPC composite structures, along with a comprehensive analysis of the load-slip curve characteristics derived from the experimental results. Subsequently, eight machine learning models were trained and tested using a database comprising 289 instances from push-out tests. Fourteen key factors were selected as input parameters, and three characteristic values including shear strength, initial shear stiffness, and peak slip were chosen as output parameters. The results indicated that the Extreme Gradient Boosting (XGBoost) model exhibited excellent performance in predicting shear strength and peak slip, with corresponding R² values of 0.988 and 0.814, respectively, while the Categorical Boosting (CatBoost) model performed best in predicting initial shear stiffness with an R² value of 0.867. Feature importance analysis using the Shapley Additive Explanations (SHAP) method highlighted that stud diameter was a critical factor affecting shear strength and initial shear stiffness, while stud height was a critical factor influencing the peak slip. Finally, based on the predicted characteristic values, an effective model was established for predicting the load-slip curve of stud connectors in steel-UHPC composite structures, which was validated to have good accuracy and applicability via the test results.
作者机构：
[Xia Yang; Jie Wu] School of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan 430023, China;[Jiuyuan Wang; Han Huang] School of Urban Construction, Yangtze University, Jingzhou 434023, China;[Gengchen Wu] Civil and Resource Engineering School, University of Science and Technology Beijing, Beijing 100083, China
通讯机构：
[Gengchen Wu] C;Civil and Resource Engineering School, University of Science and Technology Beijing, Beijing 100083, China
摘要：
The proposal of under-seawater 3D concrete printing (US3DCP) technique offers a promising solution to marine engineering construction and ocean energy development. It addresses the technical challenges in traditional underwater construction, for instance, poor working security, inaccurate placement and poor construction quality. To promote the application of US3DCP in actual engineering projects, a cement-based material available for the printing condition of under seawater was designed and produced in this study, validating the feasibility of US3DCP. Considering the variables of curing age and load direction, the compressive strength and flexural strength of concrete printed under seawater was compared with that of samples printed in air and underwater. It is recommended that an anti-washout admixture (AWA) content of 2 % and a sulphoaluminate cement (SAC) content of 25 % led to high washout resistance and good printability. The mechanical anisotropy of 3D-printed concrete is independent of printing conditions. After 28-day of curing age, the compressive strength of underwater and under seawater samples were 0.87 and 1.02 times that of air samples, and their flexural strength were 8 % and 5 % lower than as compared to air samples. Finally, the impact mechanism of printing conditions on the mechanical properties of 3D-printed concrete was analyzed from a microscopic perspective.
The proposal of under-seawater 3D concrete printing (US3DCP) technique offers a promising solution to marine engineering construction and ocean energy development. It addresses the technical challenges in traditional underwater construction, for instance, poor working security, inaccurate placement and poor construction quality. To promote the application of US3DCP in actual engineering projects, a cement-based material available for the printing condition of under seawater was designed and produced in this study, validating the feasibility of US3DCP. Considering the variables of curing age and load direction, the compressive strength and flexural strength of concrete printed under seawater was compared with that of samples printed in air and underwater. It is recommended that an anti-washout admixture (AWA) content of 2 % and a sulphoaluminate cement (SAC) content of 25 % led to high washout resistance and good printability. The mechanical anisotropy of 3D-printed concrete is independent of printing conditions. After 28-day of curing age, the compressive strength of underwater and under seawater samples were 0.87 and 1.02 times that of air samples, and their flexural strength were 8 % and 5 % lower than as compared to air samples. Finally, the impact mechanism of printing conditions on the mechanical properties of 3D-printed concrete was analyzed from a microscopic perspective.
作者：
Shuqing Sun;Hongwei Li;Sulan Li;Feifan Feng;Zhiwei Liu
作者机构：
[Zhiwei Liu] Wuhan Polytechnic University, School of Civil Engineering and Architecture, Wuhan, Hubei, China [email protected];[Sulan Li] Jianghan University, State Key Laboratory of Precision Blasting, Wuhan, Hubei, China [email protected];[Shuqing Sun; Hongwei Li; Feifan Feng] Hohai University, College of Civil and Transportation Engineering, Nanjing, Jiangsu, China [email protected]
会议名称：
SCSD '25: Proceedings of the 2025 International Conference on Smart City and Sustainable Development
摘要：
This study used a controlled interruption time series to analyze the impact of Chica-go's COVID-19 policies on traffic safety, including stay-home orders, cautious reopening, gradual return, second wave of restrictions, restrictions lifed, and the new normal. The heterogeneity of policy effects among different population groups is also consid-ered. The results showed that: 1) Stay-at-home order and cautious opening policy had adverse effects on the casualty rate, and the effect of cautious opening policy was more significant;The stay-at-home order led to a spike in injury rates only in the first few weeks, while the rate continued to rise during the cautious reopening, suggesting that the policy could have long-term adverse effects. 2) The reduction in mortality rates under the new normal phase was the most significant among all the reopening stages, and by the end of 2021, overall mortality rates returned to levels seen in previous years. 3) Males faced higher risks during lockdowns and initial reopening, whereas females experi-enced increased casualties during commercial or entertainment venue reopenings. 4) Casualty rates for cyclists and pedestrians were less affected by the blockade and initial reopening. However, pedestrian casualty rates increased during the reopening phase, especially after the reopening of the recreational and commercial sectors. 5) Young people had lower casualty rates during the reopening phase, but their rise was more pronounced during the lockdown. In terms of casualty rate, the elderly are less sensi-tive to policy interventions. These findings highlight the need to consider phased changes in travel patterns and demographic differences when formulating traffic management strategies at different stages of a pandemic.
摘要：
Marine soft clay is characterized by a high water content and low strength, exhibiting pronounced creep deformation under long-term loading that threatens the serviceability and durability of coastal infrastructure. Accordingly, this study develops a creep constitutive model that combines elastic, plastic, and viscous effects and quantitatively evaluates time-dependent deformation under varying water contents and stress levels to provide reliable prediction tools for tunnel, excavation, and pile-foundation design. Cyclic creep tests were carried out on reconstituted marine soft clay with water contents of 40–60% and stress ratios of 0.4–1.2 using a pneumatic, fully digital, closed-loop triaxial apparatus. A “nonlinear spring–Bingham slider–dual viscous dashpot in parallel with a standard Kelvin dashpot” element assembly was proposed, and the complete stress–strain relationship was derived. Experimental data were fitted with Python to generate a creep-strain polynomial and verify the model accuracy. The predicted–measured creep difference remained within 10%, and the surface-fit coefficient of determination reached R2 = 0.97, enabling rapid estimation of deformation for the given stress and time conditions. The findings offer an effective method for the precise long-term settlement prediction of marine soft clay and significantly enhance the reliability of the deformation assessments in coastal civil-engineering projects.
摘要：
The synthesis of dimethylaminopropylmethacrylamide-benzylammonium chloride (QD-BC), a kind of acrylamide quaternary ammonium salt, through the combination of N-dimethylamine propyl methacrylamide and benzyl chloride (BC) is presented in this paper. The structure of QD-BC was analyzed using FTIR, carbon spectrum, mass spectrometry and 1HNMR spectroscopy. The resulting product was then utilized for the preparation of light-cured antimicrobial coatings. The mechanical properties of the light-cured coatings were evaluated through drawing tests, etc. The antimicrobial efficacy of coatings with varying contents of QD-BC against E. coli and S. aureus was investigated. The results indicate that the coating with the QD-BC content of 7.2% exhibits maximum adhesion strength, reaching 0.87 MPa. Moreover, when the QD-BC content is 6%, the coating displays a hardness value of 5H while maintaining good flexibility throughout all formulations tested. The coating with QD-BC content of 7.5% shows the highest impact strength among all compositions studied. Furthermore, at respective concentrations of 7.5% and 4.2% for the E. coli and S. aureus testing strains, these coatings demonstrate complete antimicrobial activity with exceptional durability.
期刊：
Journal of Applied Polymer Science,2025年:e57388 ISSN：0021-8995
通讯作者：
Xu, Y
作者机构：
[Wang, Yuansheng; Hu, Yiming] Naval Univ Engn, Coll Naval Architecture & Ocean Engn, Wuhan, Peoples R China.;[Xu, Yan; Tan, Xiaoming; Liu, Qinyi; Xu, Y; Fang, Tao] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan, Peoples R China.;[He, Jiaxuan; Wang, Zhen] Huazhong Univ Sci & Technol, Sch Mat Sci & Engn, State Key Lab Mat Proc & Die & Mold Technol, Wuhan, Peoples R China.;[Zhou, Shengtai] Sichuan Univ, Polymer Res Inst, Natl Key Lab Adv Polymer Mat, Chengdu, Peoples R China.
通讯机构：
[Xu, Y ] W;Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan, Peoples R China.
关键词：
coatings;composites;functionalization of polymers;hydrophilic polymers
摘要：
Marine biofouling poses a threat to marine facilities. In this work, a quaternary ammonium salt (E54-QAS) was synthesized from triethylammonium hydrochloride and epoxy resin E-54, which was then incorporated into a polyurethane (PU) prepolymer to fabricate an antifouling coating. The coating exhibited a bonding strength as high as 3.12 MPa and impact resistance of 90 kg as well as excellent antibacterial efficiency against Pseudomonas aeruginosa at an E54-QAS content of 4.2%. Moreover, the antimicrobial efficacy of the coating remained above 99% after 3 months of immersion. The optimized formulation effectively inhibited diatom growth and adhesion, demonstrating superior antifouling performance and long-term efficacy. The coating shows promising application in maritime vessels, nuclear power plants, and offshore platforms, offering an effective solution to marine biofouling issues.
摘要：
Rapid urban industrialization has significantly increased the generation of industrial solid waste, posing substantial challenges for its effective and sustainable disposal. This study utilizes industrial waste combined with construction waste (CW) to solidify dredged sediment (DS), resulting in the creation of a novel solid waste-based landfill cover material (GH). After 20 dry-wet cycles, GH retained favorable mechanical performance, with compressive strength ranging from 4.31 to 6.83 MPa, volumetric shrinkage between 1.56% and 2.96%, and a stabilized permeability coefficient of 8.74 x 10- 8-1.412 x 10- 7 cm/s. Furthermore, the GH material functions as an impermeable layer within landfill cover systems, which were evaluated through a field-scale model test. The cover system at a depth of 40-60 cm exhibited the most substantial recharge from rainfall, with volumetric water contents were 17.97-51.19%. The GH at the bottom of the model box did not achieve saturation at any point during the experiment. A comprehensive characterization of the GH was conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The solidification mechanisms of industrial solid waste and municipal construction waste in lake sediment were elucidated. This study pioneers the solidification of lake sediment using industrial and construction waste to develop a solid waste-based landfill cover material, addressing both waste management and environmental sustainability. By converting harmful waste into a durable, low-permeability material, this research presents a sustainable strategy for mitigating landfill pollution and reducing carbon emissions. This approach not only promotes waste recycling but also improves the mechanical and environmental performance of landfill covers, representing a notable advancement in sustainable geotechnical engineering.
摘要：
At present, China's prefabricated buildings have entered a period of comprehensive development. Starting from the investment decision-making stage of construction projects, this paper analyses the characteristics of prefabricated investment estimation and the relevant literature on the characteristics of prefabricated construction projects, uses the rough set attribute reduction algorithm to screen the key engineering characteristic factors, and establishes a BP neural network model optimized by genetic algorithm to estimate and analyze the investment of completed prefabricated construction projects. The results of the study show that the accuracy of the improved BP neural network prediction model is better than that of the standard BP neural network prediction model, and the results are more stable, which provides a more scientific and effective method for the investment estimation of prefabricated buildings projects.
作者机构：
[Bairu Xiao; Feng Xu; Zhangyueer Yan; Junkun Zhang; Siyue Zhu] Wuhan Polytechnic University, School of Civil Engineering and Architecture, Wuhan, Hubei, China [email protected]
会议名称：
SCSD '25: Proceedings of the 2025 International Conference on Smart City and Sustainable Development
摘要：
The emergence of new quality productive forces has served as robust impetus for the transformation and upgrading of the construction industry. To systematically investigate the synergistic effects arising from the integration of artificial intelligence (AI) with construction practices, this study categorizes AI applications into three phases: design, construction, and operation and maintenance (O&M). In the design phase, Building Information Modeling (BIM) and generative AI are synergistically employed to optimize architectural solutions. During the construction phase, intelligent construction robots, 5G-enabled tower cranes and other automated equipments are integrated with BIM and Augmented Reality (AR) platforms. This combination increases managerial and operational efficiency. For the O&M phase, a digital twin platform supported by Internet of Things (IoT) networks and AI-driven predictive analytics enables preventive equipment maintenance and energy consumption optimization. Taking Xiong'an New Area as a representative case study, this research demonstrates that the symbiotic integration of AI technologies with construction substantial improvements across project lifecycles, operational efficiency, and safety performance. These advancements provide both practical evidence and technical pathways to support future urban renewal initiatives.
摘要：
Solid waste-based cementitious materials represent a promising alternative to conventional Portland cement, contributing to a reduction in carbon dioxide emissions and enhancing the recycling of industrial and municipal waste. However, these materials are susceptible to harsh environmental conditions, such as sulphate attack, which may result in expansion, strength degradation, and alterations in permeability. This study systematically investigated the effects of sulphate exposure on the mechanical properties and permeability of cementitious materials derived from industrial and municipal solid wastes, such as blast furnace slag, desulphurisation gypsum, construction waste, and municipal sludge. Microstructural and chemical characterisation was performed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). In sulphate solutions ranging from 0.2 to 50 g/L, the unconfined compressive strength of these materials increased by 5.8% to 24.8% during the initial 10 days of exposure, before decreasing to 4.13–9.18 MPa after 90 days. Sulphate reactions with industrial waste components resulted in the formation of expansive phases, such as ettringite and gypsum dihydrate, leading to structural degradation. The particle size of construction waste and the slag content significantly influenced the rate of sulphate-induced degradation.
Solid waste-based cementitious materials represent a promising alternative to conventional Portland cement, contributing to a reduction in carbon dioxide emissions and enhancing the recycling of industrial and municipal waste. However, these materials are susceptible to harsh environmental conditions, such as sulphate attack, which may result in expansion, strength degradation, and alterations in permeability. This study systematically investigated the effects of sulphate exposure on the mechanical properties and permeability of cementitious materials derived from industrial and municipal solid wastes, such as blast furnace slag, desulphurisation gypsum, construction waste, and municipal sludge. Microstructural and chemical characterisation was performed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). In sulphate solutions ranging from 0.2 to 50 g/L, the unconfined compressive strength of these materials increased by 5.8% to 24.8% during the initial 10 days of exposure, before decreasing to 4.13–9.18 MPa after 90 days. Sulphate reactions with industrial waste components resulted in the formation of expansive phases, such as ettringite and gypsum dihydrate, leading to structural degradation. The particle size of construction waste and the slag content significantly influenced the rate of sulphate-induced degradation.
摘要：
This study investigates the breakpoint chlorination process and its impact on fungal spore and bacterial inactivation, focusing on the dynamic role of chloramines. Using Aspergillus niger and Bacillus subtilis as model microorganisms, a three-stage inactivation pattern driven by varying Cl 2 /N ratios was revealed. As Cl 2 /N increases, the overall disinfection efficiency improves, with free chlorine dominating bacterial inactivation beyond the breakpoint. However, for fungal spores, monochloramine (NH 2 Cl) remains the primary inactivating agent even as Cl 2 /N approaches and surpasses the breakpoint. At the peak chloramination stage, NH 2 Cl contributes 94 % of fungal inactivation, exploiting its superior ability to penetrate the robust, multilayered spore wall, compared to only 71 % for bacteria. In contrast, the oxidative potential of free chlorine is more effective against the simpler bacterial cell wall. These findings emphasize the pivotal role of peak chloramination in fungal control, as NH 2 Cl demonstrates superior cost−efficiency and inactivation performance during this stage. Although free chlorine provides broad−spectrum pathogen coverage beyond the breakpoint, targeting fungal spores effectively requires leveraging the unique advantages of NH 2 Cl. This study provides valuable insights for optimizing disinfection strategies by balancing Cl 2 /N ratios to enhance microbial inactivation while minimizing operational costs and disinfection byproduct risks.
This study investigates the breakpoint chlorination process and its impact on fungal spore and bacterial inactivation, focusing on the dynamic role of chloramines. Using Aspergillus niger and Bacillus subtilis as model microorganisms, a three-stage inactivation pattern driven by varying Cl 2 /N ratios was revealed. As Cl 2 /N increases, the overall disinfection efficiency improves, with free chlorine dominating bacterial inactivation beyond the breakpoint. However, for fungal spores, monochloramine (NH 2 Cl) remains the primary inactivating agent even as Cl 2 /N approaches and surpasses the breakpoint. At the peak chloramination stage, NH 2 Cl contributes 94 % of fungal inactivation, exploiting its superior ability to penetrate the robust, multilayered spore wall, compared to only 71 % for bacteria. In contrast, the oxidative potential of free chlorine is more effective against the simpler bacterial cell wall. These findings emphasize the pivotal role of peak chloramination in fungal control, as NH 2 Cl demonstrates superior cost−efficiency and inactivation performance during this stage. Although free chlorine provides broad−spectrum pathogen coverage beyond the breakpoint, targeting fungal spores effectively requires leveraging the unique advantages of NH 2 Cl. This study provides valuable insights for optimizing disinfection strategies by balancing Cl 2 /N ratios to enhance microbial inactivation while minimizing operational costs and disinfection byproduct risks.
摘要：
For existing advantages in resource recovery and cost, anaerobic digestion (AD) is considered a proper technology to treat sludge. The insufficient efficiency of sludge AD however prevents its further application. This work reported a hybrid method by combining calcium hypochlorite (CH) with ultrasound (US) for sludge pretreatment to enhance the AD performance. Experimental data demonstrated that the optimal parameters of this co-treatment were CH at 0.08 g/g volatile suspended solids (VSS) coupled with US intensity of 1.0 W/mL, and relevant biomethane yield was 263.4 mL/g VSS, 15.2%, 23.1% and 56.6% higher than individual CH, individual US and control, respectively. Simulation results showed that methane production potential and rate both increased under CH + US condition. Mechanism analysis indicated that abundant dissolved organic matters were generated through high-efficiency hydrolysis when sludge was treated with CH + US, because extracellular polymeric substances (EPS) and microbial cells were both sufficiently disrupted in treatment process. Gene analysis revealed that functional microbes were generally enriched by the co-treatment, and their total abundance markedly improved from 11.89% to 24.87% under CH + US condition.
For existing advantages in resource recovery and cost, anaerobic digestion (AD) is considered a proper technology to treat sludge. The insufficient efficiency of sludge AD however prevents its further application. This work reported a hybrid method by combining calcium hypochlorite (CH) with ultrasound (US) for sludge pretreatment to enhance the AD performance. Experimental data demonstrated that the optimal parameters of this co-treatment were CH at 0.08 g/g volatile suspended solids (VSS) coupled with US intensity of 1.0 W/mL, and relevant biomethane yield was 263.4 mL/g VSS, 15.2%, 23.1% and 56.6% higher than individual CH, individual US and control, respectively. Simulation results showed that methane production potential and rate both increased under CH + US condition. Mechanism analysis indicated that abundant dissolved organic matters were generated through high-efficiency hydrolysis when sludge was treated with CH + US, because extracellular polymeric substances (EPS) and microbial cells were both sufficiently disrupted in treatment process. Gene analysis revealed that functional microbes were generally enriched by the co-treatment, and their total abundance markedly improved from 11.89% to 24.87% under CH + US condition.
期刊：
Construction and Building Materials,2025年476:141240 ISSN：0950-0618
通讯作者：
Zhong, J;Sun, YB
作者机构：
[Zhong, Jing; Zhong, J; Sun, Shangyu; Zhang, Ming] Harbin Inst Technol, Sch Civil Engn, Harbin 150001, Peoples R China.;[Zhang, Ming] China State Construct Int Holdings Ltd, Hong Kong 999077, Peoples R China.;[Hu, Pengfei] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.;[Yao, Jie] China State Construct Hailong Technol Co Ltd, Shenzhen 518000, Peoples R China.;[Sun, Yubo; Sun, YB] Hong Kong Polytech Univ, Dept Civil & Environm Engn, Hong Kong 999077, Peoples R China.
通讯机构：
[Zhong, J ; Sun, YB ] H;Harbin Inst Technol, Sch Civil Engn, Harbin 150001, Peoples R China.;Hong Kong Polytech Univ, Dept Civil & Environm Engn, Hong Kong 999077, Peoples R China.
摘要：
The global surge in construction has intensified demand for natural silica sand (SS), causing shortages due to unsustainable extraction. This study explores the potential of using desert sand (DS) as an alternative to SS in producing ultra-high-performance alkali-activated concrete (UHPAAC), emphasizing the interactions between aggregates and the binding matrix. DS demonstrated a smoother surface morphology, finer particles, and a narrower gradation compared to SS. Substituting SS with DS at varying volume ratios improved the concentration of several elements in the pore solution of fresh mixtures. Samples with 10 vol% DS achieved the highest compressive strength, about 20 % higher than the SS reference mix. However, higher DS content reduced mechanical performance. Investigations of reaction products and microstructural characteristics revealed changes in the binder phase, including a lower Ca/Si ratio and improved local elastic modulus when DS was incorporated. Additionally, the smaller grain sizes of DS created numerous interfaces with the binding matrix, resulting in a more porous microstructure and declined micromechanical properties in the interfacial transition zone (ITZ) compared to SS. Nevertheless, the strategic incorporation of DS as a partial replacement for SS enhances both compressive and flexural strength while simultaneously reducing the environmental impact of UHPAAC production.
The global surge in construction has intensified demand for natural silica sand (SS), causing shortages due to unsustainable extraction. This study explores the potential of using desert sand (DS) as an alternative to SS in producing ultra-high-performance alkali-activated concrete (UHPAAC), emphasizing the interactions between aggregates and the binding matrix. DS demonstrated a smoother surface morphology, finer particles, and a narrower gradation compared to SS. Substituting SS with DS at varying volume ratios improved the concentration of several elements in the pore solution of fresh mixtures. Samples with 10 vol% DS achieved the highest compressive strength, about 20 % higher than the SS reference mix. However, higher DS content reduced mechanical performance. Investigations of reaction products and microstructural characteristics revealed changes in the binder phase, including a lower Ca/Si ratio and improved local elastic modulus when DS was incorporated. Additionally, the smaller grain sizes of DS created numerous interfaces with the binding matrix, resulting in a more porous microstructure and declined micromechanical properties in the interfacial transition zone (ITZ) compared to SS. Nevertheless, the strategic incorporation of DS as a partial replacement for SS enhances both compressive and flexural strength while simultaneously reducing the environmental impact of UHPAAC production.
期刊：
KSCE Journal of Civil Engineering,2025年29(8):100156 ISSN：1226-7988
通讯作者：
Fu, D
作者机构：
[Hu, Lei] Minist Water Resources MWR, Changjiang River Sci Res Inst CRSRI, Hubei Technol Innovat Ctr Smart Hydropower, Natl Dam Safety Res Ctr, Jiuwanfang Rd,Huangpu St, Wuhan, Hubei, Peoples R China.;[Hu, Lei] Minist Water Resources MWR, Changjiang River Sci Res Inst CRSRI, Res Ctr Water Engn Safety & Disaster Prevent, Jiuwanfang Rd,Huangpu St, Wuhan, Hubei, Peoples R China.;[Xiang, Ai-Jun; Li, Hu; Hu, Xing; Liu, Dong] China Yangtze Power Co Ltd, Hubei Technol Innovat Ctr Smart Hydropower, Jianshe Rd,Xiling St, Yichang, Hubei, Peoples R China.;[Fu, Dan] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Xuefu South Rd, Wuhan, Hubei, Peoples R China.
通讯机构：
[Fu, D ] W;Wuhan Polytech Univ, Sch Civil Engn & Architecture, Xuefu South Rd, Wuhan, Hubei, Peoples R China.
关键词：
Spiral case structure;Inconsistent gap-closing behavior;IWP-transferring percentage;Operational safety;Steel-concrete composite structure
摘要：
To withstand the internal water pressure (IWP) in hydroelectric power plants (HPPs), this study designs a spiral case structure (SCS). It can be considered a composite structure made of steel and concrete. The steel component is typically called a steel spiral case (SSC). An SSC embedded in a pressurized condition is featured by the gap between the steel liner the concrete. Seeing that the conventional knowledge concerning gap-closure behavior is challenged by some in-situ data, the present study conducts a complete simulation procedure with the ABAQUS program. The numerical simulations are reasonably consistent with the experimental results. The novelty of this paper is the investigation of the mechanism of the inconsistent gap-closing behavior in SCSs of HPPs and its structural role. It has two significant findings: (a) a strong link has been found between the inconsistent gap-closing phenomenon and the hydraulic thrust on the SSC along the axis of its inlet; and (b) the structural role of the gap closure in affecting the IWP-transferring behavior in SCSs is underlined. The present findings highlight that the gap-closure behavior should be carefully considered in the structural design of SCSs as it has significant effects on the structural and operational safety of HPPs.
摘要：
This study investigates the development of Alkali-activated Ultra-high performance concrete (AAUHPC) incorporating steel slag powder (SS), ground granulated blast furnace slag (GGBFS), silica fume, and hooked-end steel fibers to achieve sustainable, high-performance construction materials. The effects of SS content (0–70 %) and steel fiber volume fraction (0–2.0 %) on workability, mechanical properties, and microstructure were systematically evaluated through a combination of macroscopic performance tests (setting time, fluidity, compressive/flexural strength, and splitting tensile strength) and microstructural analyses (hydration heat, mercury intrusion porosimetry, X-ray computed tomography, scanning electron microscopy, and micro-hardness). Results reveal that AAUHPC containing 30 % SS and 2.0 % steel fibers achieves a fluidity of 190 mm and a compressive strength of 155.4 MPa at 28 days. Steel slag powder enhances the workability of fresh AAUHPC by extending setting time and improving fluidity, which can be attributed to its lower reactivity and reduced water demand compared to GGBFS. However, excessive SS content (>30 %) may dilute reactive phases and hinder hydration kinetics, leading to decreased mechanical strengths. Although hooked-end steel fibers slightly reduce fluidity, they significantly enhance toughness; specially, a 2.0 % volume fraction yields an 89.8 % increase in flexural strength (18.34 MPa) and a splitting tensile strength of 20.12 MPa, thereby enabling strain-hardening behavior comparable to cement-based UHPC. Microstructural analysis confirms a robust interfacial bonding between fibers and the alkali-activated matrix, facilitated by C-S-H and C-(N,K)-A-S-H gels. This phenomenon has significantly contributed to the high strength and toughness exhibited by AAUHPC. The findings underscore the potential of steel slag powder as a sustainable precursor for applications involving AAUHPC, while also demonstrating the compatibility of alkali-activated materials with hooked-end steel fibers.
This study investigates the development of Alkali-activated Ultra-high performance concrete (AAUHPC) incorporating steel slag powder (SS), ground granulated blast furnace slag (GGBFS), silica fume, and hooked-end steel fibers to achieve sustainable, high-performance construction materials. The effects of SS content (0–70 %) and steel fiber volume fraction (0–2.0 %) on workability, mechanical properties, and microstructure were systematically evaluated through a combination of macroscopic performance tests (setting time, fluidity, compressive/flexural strength, and splitting tensile strength) and microstructural analyses (hydration heat, mercury intrusion porosimetry, X-ray computed tomography, scanning electron microscopy, and micro-hardness). Results reveal that AAUHPC containing 30 % SS and 2.0 % steel fibers achieves a fluidity of 190 mm and a compressive strength of 155.4 MPa at 28 days. Steel slag powder enhances the workability of fresh AAUHPC by extending setting time and improving fluidity, which can be attributed to its lower reactivity and reduced water demand compared to GGBFS. However, excessive SS content (>30 %) may dilute reactive phases and hinder hydration kinetics, leading to decreased mechanical strengths. Although hooked-end steel fibers slightly reduce fluidity, they significantly enhance toughness; specially, a 2.0 % volume fraction yields an 89.8 % increase in flexural strength (18.34 MPa) and a splitting tensile strength of 20.12 MPa, thereby enabling strain-hardening behavior comparable to cement-based UHPC. Microstructural analysis confirms a robust interfacial bonding between fibers and the alkali-activated matrix, facilitated by C-S-H and C-(N,K)-A-S-H gels. This phenomenon has significantly contributed to the high strength and toughness exhibited by AAUHPC. The findings underscore the potential of steel slag powder as a sustainable precursor for applications involving AAUHPC, while also demonstrating the compatibility of alkali-activated materials with hooked-end steel fibers.
摘要：
It is highly feasible to utilize phase change energy storage technology to construct a phase change material (PCM)-based thermal management system for electronic devices. In this paper, stearic acid (SA) was used as the PCM, and expanded graphite (EG) was chosen as the carrier to prepare SA/EG CPCM. The results showed that EG could prevent the melted SA from leaking, and the combination between SA and EG was only physical. When the mass fraction of EG was 11%, the SA/EG CPCM had good shape stability with a phase change temperature (T-m) of 67.2 degrees C, a phase change enthalpy (triangle H-m) of 204.4 J/g, and a significantly increased in thermal conductivity (6.432 W/(m<middle dot>K)). In addition, simulation test experiments showed that the peak value of the heating surface was weakened by about 20 degrees C in the heating stage after loading the CPCM on the electronic device. Therefore, the resultant SA/EG CPCM in this work had great application value.
期刊：
Journal of Building Engineering,2025年105:112474 ISSN：2352-7102
通讯作者：
Li, ZP
作者机构：
[Gong, Jing; Liu, Jiesheng] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.;[Gong, Jing] Wuchang Univ Technol, Intelligent Construct Coll, Wuhan 430223, Peoples R China.;[Chen, Chaoqian] Int Water Resources & Hydropower Engn Construct Co, Wuhan 460050, Peoples R China.;[Li, Zhipeng; Li, ZP] Washington State Univ, Dept Civil & Environm Engn, Pullman, WA 99164 USA.;[Li, Zhipeng] CarbonSilvanus Co, Pullman, WA 99163 USA.
通讯机构：
[Li, ZP ] W;Washington State Univ, Dept Civil & Environm Engn, Pullman, WA 99164 USA.
关键词：
Class F fly ash;Municipal solid waste incineration fly ash (MSWIA);Mechanical strength;Deconvoluted Fourier transform infrared (FTIR) spectroscopy;Hydration products
摘要：
Class F fly ash (FA) is often limited in its application in the concrete industry due to its low hydration reactivity. This study explores the synergistic utilization of municipal solid waste incineration fly ash (MSWIA) and FA to valorize these two industrial waste streams for application in the concrete industry, aimed to reduce the carbon footprint associated with extensive cement use. The study proposes replacing part of the cement with MSWIA and Class F FA, with a baseline mix ratio of MSWIA: FA: Cement = 40 %:40 %:20 %. In addition, silica fume (SF), nano-montmorillonite (nMMT), and calcium oxide (CaO) were added to the system to modify and activate the binder, with the goal of meeting practical engineering requirements. Experimental results indicate that the optimal dosages are 15 % SF/(FA + MSWIA), 0.3 % nMMT/(FA + MSWIA), and 3 % CaO/(FA + MSWIA), achieving a 28-day compressive strength of 21.1 MPa, which represents an increase of 186 % compared with the control group. Furthermore, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and deconvoluted Fourier transform infrared spectroscopy (FTIR) were used to investigate the effects of various variables on the microstructural morphology, hydration process, and hydration products of the paste samples. The results demonstrate that the addition of SF, nMMT, and CaO not only promotes the formation of highly polymerized hydration products, refines the pore structure, and improves the microstructural compactness but also significantly enhances the overall mechanical properties and durability of the cementitious system.
Class F fly ash (FA) is often limited in its application in the concrete industry due to its low hydration reactivity. This study explores the synergistic utilization of municipal solid waste incineration fly ash (MSWIA) and FA to valorize these two industrial waste streams for application in the concrete industry, aimed to reduce the carbon footprint associated with extensive cement use. The study proposes replacing part of the cement with MSWIA and Class F FA, with a baseline mix ratio of MSWIA: FA: Cement = 40 %:40 %:20 %. In addition, silica fume (SF), nano-montmorillonite (nMMT), and calcium oxide (CaO) were added to the system to modify and activate the binder, with the goal of meeting practical engineering requirements. Experimental results indicate that the optimal dosages are 15 % SF/(FA + MSWIA), 0.3 % nMMT/(FA + MSWIA), and 3 % CaO/(FA + MSWIA), achieving a 28-day compressive strength of 21.1 MPa, which represents an increase of 186 % compared with the control group. Furthermore, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and deconvoluted Fourier transform infrared spectroscopy (FTIR) were used to investigate the effects of various variables on the microstructural morphology, hydration process, and hydration products of the paste samples. The results demonstrate that the addition of SF, nMMT, and CaO not only promotes the formation of highly polymerized hydration products, refines the pore structure, and improves the microstructural compactness but also significantly enhances the overall mechanical properties and durability of the cementitious system.
期刊：
Construction and Building Materials,2025年488:142158 ISSN：0950-0618
通讯作者：
Lan, JR
作者机构：
[Zou, Nachuan; Lu, Haijun; Dong, Yiqie; Zang, Meng] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.;[Lan, Jirong] Hong Kong Polytech Univ, Civil & Environm Engn, Hong Kong, Peoples R China.;[Huang, Bo-Tao] Zhejiang Univ, Inst Adv Engn Struct, Hangzhou, Peoples R China.
通讯机构：
[Lan, JR ] H;Hong Kong Polytech Univ, Civil & Environm Engn, Hong Kong, Peoples R China.
关键词：
Phosphogypsum;Grinding kinetics;Fractal theory;Activity index
摘要：
Mechanical ball milling significantly enhances the recovery rate and utilization efficiency of phosphogypsum (PPG). This study investigates the mechanical activation of PPG. Mechanical ball milling was conducted at a speed of 300 r/s for periods ranging from 30 to 120 min. The particle composition and structure of activated PPG were analyzed using laser particle size testing. The grinding kinetics mechanism was analyzed based on classification theory, and its chemical activity was characterized through activity index testing. Results indicate that after 30 min of grinding, the median particle size of PPG powder increases to 83.42 μm. The specific surface area reaches 5.2729 m²/g, and the morphology shows agglomeration, forming spherical structures of varying sizes. When grinding exceeds 60 min, the median particle size of PPG decreases to 32.45–37.88 μm. The spherical structures shatter and become irregular fragments. The Swebrec function and RRB are suited for describing the grinding kinetics of PPG in the initial (less than 60 min) and the later (more than 60 min) stage of grinding, respectively, and the fractal characteristic curve of PPG powder adheres to a linear fitting law. As curing time increases, the activity index of PPG cement mortar test blocks rises by 30.7–56.5 %. After 28 days of curing, the highest activity index value exceeds 75 %, meeting the requirements for S75 grade slag grinding particles according to the Chinese national standard GB/T 18046–2017.
Mechanical ball milling significantly enhances the recovery rate and utilization efficiency of phosphogypsum (PPG). This study investigates the mechanical activation of PPG. Mechanical ball milling was conducted at a speed of 300 r/s for periods ranging from 30 to 120 min. The particle composition and structure of activated PPG were analyzed using laser particle size testing. The grinding kinetics mechanism was analyzed based on classification theory, and its chemical activity was characterized through activity index testing. Results indicate that after 30 min of grinding, the median particle size of PPG powder increases to 83.42 μm. The specific surface area reaches 5.2729 m²/g, and the morphology shows agglomeration, forming spherical structures of varying sizes. When grinding exceeds 60 min, the median particle size of PPG decreases to 32.45–37.88 μm. The spherical structures shatter and become irregular fragments. The Swebrec function and RRB are suited for describing the grinding kinetics of PPG in the initial (less than 60 min) and the later (more than 60 min) stage of grinding, respectively, and the fractal characteristic curve of PPG powder adheres to a linear fitting law. As curing time increases, the activity index of PPG cement mortar test blocks rises by 30.7–56.5 %. After 28 days of curing, the highest activity index value exceeds 75 %, meeting the requirements for S75 grade slag grinding particles according to the Chinese national standard GB/T 18046–2017.
