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Feasibility analysis of 3D printed concrete with sludge incineration slag: Mechanical properties and environmental impacts

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CONSTRUCTION AND BUILDING MATERIALS 2024年 449卷

作者： Shen, Kaige Ding, Tao Cai, Chen xiao, Jianzhuang xiao, xuwen Liang, Wan Tongji Univ Coll Civil Engn Dept Struct Engn Shanghai 200092 Peoples R China Tongji Univ Coll Environm Sci & Engn Shanghai 200092 Peoples R China Tongji Univ Inst Carbon Neutral Shanghai 200092 Peoples R China Shanghai Guohui Environm Protect Technol Grp Co Lt Shanghai 201702 Peoples R China

This study substituted sludge incineration slag for natural sand in the application of 3D printed concrete technology (3DCP). It analyzed the influence of the sludge incineration slag incorporation on the workability, printability, mechanical properties, and the solidifying effect of heavy metals in 3DCP. Furthermore, the environmental and economic benefits were also examined. The results indicated that the incorporation of sludge incineration slag accelerated the loss of workability factors such as flowability and consistency in 3DCP. However, it significantly enhanced the early strength of 3DCP and improved its buildability. Additionally, the addition of sludge incineration slag diminished the mechanical properties of 3DCP. When the substitution rate reached 50 % of natural sand with sludge incineration slag, the strength of the 3D printed specimens decreased by 22.1 %. Experimental investigations at a micro-scale indicated that the porosity of interlayer interfaces was a crucial factor causing strength reduction and could be ameliorated by appropriately increasing the extrusion amount to address excessive pore sizes. Toxicity leaching tests for heavy metals demonstrated that the maximum heavy metal leaching concentration in 3DCP specimens with sludge incineration slag incorporation was 0.14 mg/ L, meeting the specified requirements. The 3DCP with sludge incineration slag incorporation not only addressed the difficulty in handling incineration bottom slag but also conserved natural sand resources, presenting outstanding environmental and economic benefits. For instance, by substituting 100 % natural sand with sludge incineration slag, there were 5 % reduction in carbon emissions and 30 % increase in economic benefits.

关键词： 3D-printed concrete Sludge incineration slag Printability Mechanical properties Environmental benefits

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3D printed concrete with sewage sludge ash: Fresh and hardened properties

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CEMENT & CONCRETE COMPOSITES 2024年 148卷

作者： Ding, Tao Shen, Kaige Cai, Chen xiao, Jianzhuang xiao, xuwen Liang, Wan Tongji Univ Coll Civil Engn Dept Struct Engn Shanghai 200092 Peoples R China Tongji Univ Coll Environm Sci & Engn Shanghai 200092 Peoples R China Tongji Univ Inst Carbon Neutral Shanghai 200092 Peoples R China Shanghai Guohui Environm Protect Technol Grp Co Lt Shanghai 201702 Peoples R China

In this study, the possibility of application of sewage sludge ash (SSA) in 3D printed concrete (3DCP) technology was explored. The replacement of partial cement with SSA in the concrete mix design was investigated, followed by a comprehensive analysis of its impact on the workability, printability, and mechanical properties of the 3DCP. The findings indicated that the incorporation of SSA accelerated the loss of workability of 3DCP, such as fluidity and consistency. However, it significantly improved the green strength and buildability. Further investigation revealed that the addition of SSA hampered the hydration process of cement, resulting in a reduction in the mechanical properties of the hardened material. CT scanning indicated that the addition of SSA increased the interlayer porosity, leading to further degradation of the mechanical properties. The toxicity characteristic leaching procedure demonstrated that the maximum leaching concentration of 3DCP incorporating SSA was 0.14 mg/L. This result confirmed the effective immobilization of heavy metals, fulfilling the prerequisites for the application of 3DCP incorporating SSA.

关键词： 3D printed concrete Sewage sludge ash Workability Printability Mechanical properties

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Rebar-free concrete construction: Concept, opportunities and challenges

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JOURNAL OF BUILDING ENGINEERING 2024年 86卷

作者： xiao, Jianzhuang Liu, Haoran Ding, Tao Yu, Kequan Zhang, Lihai xiao, xuwen Zhu, Hehua Guangxi Univ Coll Civil & Architectural Engn Nanning 530004 Peoples R China Guangxi Univ Inst Sci & Technol Carbon Peak & Neutral Nanning 530004 Peoples R China Tongji Univ Coll Civil Engn Shanghai 200092 Peoples R China Univ Melbourne Dept Infrastructure Engn Melbourne Vic 3010 Australia Chinese Acad Engn Beijing 100088 Peoples R China

To tackle the challenges associated with traditional reinforced concrete structures, such as laborintensive construction and durability deterioration over time, this paper proposes an innovative concept called rebar-free concrete construction (RFCC) and explores its potential for future development. Three key aspects of RFCC, including materials, structures, and construction technologies, are comprehensively investigated in this study. It reveals that fiber-reinforced concrete is a promising material for RFCC as it addresses challenges related to load-carrying capacity, ductility, and compatibility with construction technologies, and reduces labor and enables construction in extreme conditions, such as lunar construction. In addition, it shows that bio-inspired structures and optimized designs can significantly contribute to RFCC through offering a balance between architectural aesthetics, load capacity, ductility, and construction efficiency. Furthermore, the paper proposes a design path for RFCC and presents its development prospects. In summary, this paper provides a comprehensive understanding of the innovative concept of RFCC and its potential for future developments. By exploring these aspects of RFCC, researchers and engineers can work towards developing sustainable and resilient construction solutions for the future.

关键词： Rebar-free concrete construction (RFCC) Fiber -reinforced concrete (FRC) 3D concrete printing Bio-inspired structure

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Seismic performance of indoor substation RC frames with combined base isolation techniques

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ENGINEERING STRUCTURES 2023年第1期284卷

作者： Yin, Congru Song, Tiange Song, xiaobin Gu, Xianglin xiao, xuwen Tongji Univ Dept Struct Engn Shanghai 200092 Peoples R China Tongji Univ Key Lab Performance Evolut & Control Engn Struct Minist Educ Shanghai 200092 Peoples R China

In order to investigate the seismic performance of indoor RC substations with combined base isolation technique under far-field earthquakes and near-fault earthquakes, a 1/4 scaled three-story RC frame model was prepared for shaking table tests. Three different model configurations were considered, namely the non-isolated model (control model), the mono-isolated model (model with lead rubber bearings), and the combined isolated model (model with lead rubber bearings and viscous dampers). Scaled transformers and GISs were also installed on the model floors to consider the influence of the electrical equipment. Typical far field and near fault seismic waves, in this study the El Centro wave and the ChiChi wave, respectively, up to a PGA of 0.44 g were used as exci-tations. It was found that LRBs worked desirably for the RC model under the El Centro wave while less effective under the ChiChi wave. The acceleration responses (roof), the inter-story shear force (1F) and the inter-story drift (2F) were reduced by use of the LRBs at most by 21%, 51% and 26%, respectively, with respect to the non-isolated model under the El Centro wave. However, under the ChiChi wave irregular torsional behavior was observed and the isolation layer displacement reached 88% of the limit value. Combined use of LRBs and VDs effectively reduced the seismic responses of the RC model under the ChiChi wave. In particular, the isolation layer displacement was reduced by 15% and the torsional displacement ratio was reduced to less than 1.15, with respect to the model with LRBs only. Considerable equipment-structure interaction was found in the RC indoor substations and increased the acceleration and the displacement responses by up to 21% and 22%, respectively, given the position and mass of the equipment in this study. Besides, the LRBs and VDs were found to be effective to reduce the equipment-structure interaction.

关键词： RC frame structure Indoor substation Shaking table test Base isolation Viscous damper Near-fault earthquake

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Structural health monitoring and performance analysis of a 12-story recycled aggregate concrete structure

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ENGINEERING STRUCTURES 2020年第0期205卷 110102-000页

作者： Wang, Chunhui xiao, Jianzhuang Zhang, Chuanzeng xiao, xuwen Tongji Univ Dept Struct Engn Shanghai 200092 Peoples R China Tongji Univ State Key Lab Disaster Reduct Civil Eng Shanghai 200092 Peoples R China Univ Siegen Dept Civil Engn D-57076 Siegen Germany

To encourage the application of recycled coarse aggregates (RCA) produced from construction and demolition (C&D) waste in newly-built structures, this study investigates the dynamic behaviors of a 12-story recycled aggregate concrete (RAC) in the operational environment through structural health monitoring (SHM), and compares with an adjacent 12-story natural aggregate concrete (NAC) structure with similar arrangements of components and structural construction. The SHM has undergone 12 months, and has provided a wealth of data detailing the dynamic behaviors with the variation in the operational environment as well as significant structural responses excited by typhoons and earthquakes. Firstly, the first 5 vibration modes of both structures are identified, and the effects of the ambient temperature, hourly mean wind speed and structural response amplitude are analyzed. A lower natural frequency and a larger damping ratio of the fundamental vibration mode of the RAC structure are found than those of the NAC structure. For both the RAC and NAC structures, the fundamental frequency increases with the increasing ambient temperature, the decreasing hourly mean wind speed, and the decreasing structural response amplitude. The opposite trend of the damping ratios is identified. Secondly, the stick-slip model is used to explain the differences between the modal parameters of the RAC and the NAC structures, and to discover the mechanism of the effects of the ambient temperature, the hourly mean wind speed, and the structural response amplitude. Thirdly, the serviceability of the RAC structure is evaluated based on the full-scale measurements during typhoons. Finally, the artificial neural network (ANN) is validated to have the capacity for predicting the modal parameters precisely, and the model error of the ANN has the potential as an indicator for detecting abnormal structural performances.

关键词： Recycled aggregate concrete Natural aggregate concrete Full-scale structure Structural health monitoring Amplitude-dependent characteristic Artificial neural network

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Principles for waste concrete recycling and basic problems of recycled concrete

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CHINESE SCIENCE BULLETIN-CHINESE 2023年第5期68卷 510-523页

作者： xiao, Jianzhuang Zhang, Hanghua Tang, Yuxiang Lu, Zhenyuan Ye, Taohua Duan, Zhenhua Sui, Tongbo xiao, xuwen Tongji Univ Coll Civil Engn Dept Bldg Engineer Shanghai 200092 Peoples R China Tongji Univ State Key Lab Disaster Reduct Civil Engineer Shanghai 200092 Peoples R China Tongji Univ Key Lab Adv Civil Engn Mat Minist Educ Shanghai 201804 Peoples R China Tongji Univ Key Lab Performance Evolut & Control Engn Struct Minist Educ Shanghai 200092 Peoples R China Sinoma Int Engn Co Ltd Beijing 100102 Peoples R China

The discovery and development of contemporary concrete have made substantial contributions to the industrial revolution and urbanization over the last two centuries. The tremendous use of concrete results in a large amount of solid waste and considerable carbon emissions. The effort on waste concrete recycling is significant and vital in light of the national strategy of "carbon peaking and neutrality". The previous research on the recycled concrete focused on the traditional ideas of aggregate substitution and parameter modification to normal concrete. However, new ideas for waste concrete recycling and low-carbon application of recycled concrete should be further investigated. The theory and methods of concrete composition, decomposition, and recycling are examined. In general, the synthesis of concrete necessitates managing the characteristics of raw ingredients to increase overall performance. A mature concrete synthesis system was established by the steady physical qualities of sand and gravels, the hydration reaction of cementitious materials, and scientific combination design. Furthermore, the changes in the physical qualities of concrete components provide a theoretical foundation for crushing and sieving to produce recycled materials. To make recycled concrete (RC), recycled aggregates (RAs) and recycled powder are employed. However, the use of RC is complicated by the uncertainty of raw material sources, variations in the hydration process and microstructures, and discrepancies in basic attributes. Multi-way modification strategies have been developed to improve the qualities of RAs and RC to realize the conversion of difficult-to-control wastes into controllable recycled materials. The qualities of RC are improved and the variability of these features is reduced by incorporating artificial intelligence technologies into the mixture design of RC based on big data. In addition, three criteria for the preparation of RC are proposed, including a safe applicat

关键词： waste concrete recycling recycled concrete recycled aggregate recycled powder full recycled aggregate concrete mixture design for recycling

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外剪内框结构体系力学计算与抗震性能

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东南大学学报(自然科学版) 2025年第1期55卷 1-8页

作者：张文津肖绪文肖建庄李水生丁陶吕凤悟周泉同济大学土木工程学院上海200092 中国建筑第八工程局有限公司上海200120 中国建筑第五工程局有限公司长沙410004

为灵活设计商场、库房等大开间建筑的内部空间,提出了一种外剪内框结构体系,即在普通框架结构四周布置剪力墙,将其作为主要抗侧力构件,内部框架结构主要承担竖向荷载。推导了外剪内框结构体系的内力分析方法,提出了框架与剪力墙相对刚... 详细信息

为灵活设计商场、库房等大开间建筑的内部空间,提出了一种外剪内框结构体系,即在普通框架结构四周布置剪力墙,将其作为主要抗侧力构件,内部框架结构主要承担竖向荷载。推导了外剪内框结构体系的内力分析方法,提出了框架与剪力墙相对刚度控制参数的计算公式与设计方法。基于某4层框架结构,设计了对应的外剪内框结构,评估了外剪内框结构体系的抗震性能与抗倒塌能力。结果表明,外剪内框结构体系内部框架柱截面面积相对较小,可以实现更大的建筑空间,框架-剪力墙相对刚度的设计方法可用于实际设计。材料用量相同时,外剪内框结构较框架结构抗震性能更好,其抗侧刚度提升30.3%,极限承载力提高7.3%,罕遇地震下基底剪力减小13.8%,顶点位移减小66.3%,最大层间位移角减小74.3%。

关键词：外剪内框结构体系剪力分担比弹性计算方法刚度设计抗震性能

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RESEARCH ON OPTIMIZATION OF AGRICULTURAL MACHINERY FAULT MONITORING SYSTEM BASED ON ARTIFICIAL NEURAL NETWORK ALGORITHM

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INMATEH-AGRICULTURAL ENGINEERING 2021年第2期64卷 297-306页

作者： Zheng, Jiaxin Li, Mei Hu, Shikang xiao, xuwen Li, Hao Li, Wenfeng Yunnan Agr Univ Engn Ctr Yunnan Colleges & Univ Plateau Character Kunming Yunnan Peoples R China Yunnan Agr Univ Key Lab Crop Prod & Smart Agr Yunnan Prov Kunming Yunnan Peoples R China Yunnan Plateau Characterist Agr Ind Res Inst Kunming 650201 Yunnan Peoples R China

Aiming at the demand of mileage statistics, work area statistics, fault site return and related data automatic retention in the current agricultural machinery reliability appraisal process, the optimization of agricultural machinery video monitoring system based on artificial neural network algorithm was studied. Together with the new video monitoring technology, the agricultural machinery GPS, GSM and fuel consumption recorder technology are combined to realize the functions of real-time data transmission, monitoring, analysis and statistics. Aiming at intelligent fault analysis, a real-time online detection mechanism is proposed, and a cloud collaborative detection mechanism is proposed to solve the problem of inaccurate offline model detection. Use plane map or satellite map to browse. Thus, an online monitoring and visual testing platform for agricultural machinery faults without real-time monitoring records is established. Finally, the test platform is tested and applied. Test results show that the algorithm can greatly shorten the training time and improve the accuracy of training model detection. With the increase of online training iterations, it is helpful to improve the detection accuracy of the generated model. In a word, the system service platform can provide scientific and transparent data for agricultural machinery fault identification, ensure the scientific, open and fair principles of agricultural machinery fault identification, and greatly improve the efficiency of agricultural machinery management.

关键词： agricultural machinery video surveillance neural network

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装配式混凝土建筑防水技术与措施

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施工技术（中英文） 2024年第17期53卷 7-14,66页

作者：冯大阔肖绪文中国建筑第七工程局有限公司河南郑州450004 郑州大学水利科学与工程学院河南郑州450001 中国建筑股份有限公司北京100029

通过大量工程实践和文献调研,深入分析装配式建筑防水的重要性,系统梳理并划分装配式混凝土建筑的防水技术和措施。重点阐述3类常用的防水结构体系和5种构造防水措施,明确装配式混凝土建筑防水工程工作重点。装配式混凝土建筑防水措施... 详细信息

通过大量工程实践和文献调研,深入分析装配式建筑防水的重要性,系统梳理并划分装配式混凝土建筑的防水技术和措施。重点阐述3类常用的防水结构体系和5种构造防水措施,明确装配式混凝土建筑防水工程工作重点。装配式混凝土建筑防水措施分为结构防水、构造防水和材料防水3类,结构防水是基础,构造防水是关键,材料防水最直接。从这3方面入手,选用整体性好的结构体系、合适的防水构造、生产质量好的预制构件,并加强储存运输过程成品保护,强化预制构件安装精度和质量,关注拼缝防水处理和密封材料施工措施,注重技术联合和产品集成应用,以切实增强装配式建筑整体性和防水性能。

关键词：装配式混凝土防水工程防水材料构造

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混凝土漂浮结构的设计简介及其可持续性提升建议

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同济大学学报（自然科学版） 2024年第12期52卷 1843-1853页

作者：肖建庄周子晗夏冰胡晓龙刘曙光肖绪文同济大学土木工程学院上海 200092 同济大学土木工程防灾国家重点实验室上海 200092 同济大学土木工程学院上海 200092

气候变化与城镇化进程使得各国土地资源日渐紧缺,漂浮结构为向海图强和城镇绿色发展提供了新思路.整理了混凝土漂浮结构在城镇民用建筑、可再生能源设施与交通设施领域的应用现状,阐明漂浮结构具有拓展用地空间、缩短施工时间、减少建... 详细信息

气候变化与城镇化进程使得各国土地资源日渐紧缺,漂浮结构为向海图强和城镇绿色发展提供了新思路.整理了混凝土漂浮结构在城镇民用建筑、可再生能源设施与交通设施领域的应用现状,阐明漂浮结构具有拓展用地空间、缩短施工时间、减少建设成本并降低环境影响的综合效益.同时,总结了漂浮结构传统设计模式下的技术要点:运动与受力分析;安全性校验;模块化设计.在总体评估的基础上提出了从结构再利用、材料再循环和组合混凝土衍生漂浮结构设计三个层面提升漂浮结构的可持续性,建议推广再生混凝土、海水海砂混凝土与组合混凝土衍生结构在漂浮结构中的应用.

关键词：漂浮结构再生混凝土海水海砂混凝土组合混凝土衍生结构可持续性

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