作者机构：
[Liu, Mengyi; Lu, Haijun; Ji, Shuang; Deng, Qingkai] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.;[Liu, Mengyi; Lu, Haijun; Wan, Yong] Chinese Acad Sci, Inst Rock & Soil Mech, State Key Lab Geomech & Geotech Engn, Wuhan 430071, Peoples R China.;[Qin, Linbo] Wuhan Univ Sci & Technol, Coll Resources & Environm Engn, Wuhan 430081, Peoples R China.
通讯机构：
[Haijun Lu; Yong Wan] S;School of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan 430023, China<&wdkj&>State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China<&wdkj&>State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
关键词：
Industrial solid waste;Landfill cover;Microstructure;Modified municipal sludge;Water permeability
摘要：
In order to prepare a new type of landfill covering material for closure, we used industrial calcium-containing waste (slag, desulfurised gypsum and fly ash) to modify the municipal dewatered sludge. Shear, infiltration and rainfall infiltration model tests were performed to obtain the shear strength parameters of the modified sludge, the hydraulic conductivity during the wet-dry cycle, and the service performance against rainfall breakdown to evaluate the service performance of the modified sludge cover (MSC). Comprehensive characterisation of the modified sludge was analysed by XRD, FTIR and SEM-EDS to revealed the mineral structure, microstructure, and modification mechanism of the sludge. The MSC samples had high shear strength and shown the characteristics of evolving from plasticity to brittleness. After curing for 14 d, the values of cohesion c and internal friction angle φ reached 150.75-384.69kPa and 37.60-57.29°, respectively. The MSC exhibited excellent anti-seepage service performance under dry and wet cycle conditions. Compared with traditional compacted clay, its hydraulic conductivity dropped by an order of magnitude, and after six wet and dry cycles, the hydraulic conductivity of the modified sludge reached stability at 1.4-7.2×10(-7) cm/s. The 60-cm-thick MSC layer can completely withstand the impact of long-term rainfall during the rainy season in the middle reaches of the Yangtze River in China. Analysis results also show that the modification mechanism of the sludge could be ascribed to the generation of dense blocks and clusters of C-S-H and C-A-S-H gels originated from SiO(2), Al(2)O(3), and CaO phases in industrial calcium-containing waste and sludge by the activation of the alkali.
通讯机构：
[Zhenhua Yao; Man Zhang] S;School of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan 430023, PR China<&wdkj&>School of Material Science and Engineering, Wuhan University of Technology, WuHan 430070, PR China
通讯机构：
[Haijun Lu] S;School of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan 430023, China<&wdkj&>State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
In order to prepare a novel landfill liner material, we used industrial calcium-containing waste (slag, fly ash, and desulfurized gypsum) to solidify municipal sludge. The mechanical and permeability properties of the solidified sludge material (SSM) were evaluated using straight shear, uniaxial compression, and permeability tests. The hydration products, microscopic morphology, and elemental composition of the SSM after the wet and dry cycles were analyzed using a combination of scanning electron microscopy (SEM + EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The SSM has high strength and low hydraulic conductivity. The values of cohesion c and internal friction angle phi reached 0.45-3.31 MPa and 6.52-36.28 degrees. The SSM exhibited a compressive strength of 0.93-11.67 MPa and hydraulic conductivity of 4.80 x 10(-9) -1.34 x 10(-7) cm/s. Analysis shows that SiO2, Al2O3, and CaO in industrial calcium-containing solid wastes and sludges produce dense bulk and agglomerated C-S-H and C-A-S-H gels under alkali excitation. The optimum ratio of sludge, desulfurized gypsum, fly ash, and slag in the solidified sludge was 1:0.61:0.62:0.54, whereas the optimum exciter was Ca(OH)(2). The SSM may be used as a good barrier material to prevent water seepage in landfills.
摘要：
The aim of this research was to examine the effects of metakaolin (MK) content and low water/ binder (w/b) ratio on the basic performance and durability properties of cement mortar. The effects of various mix proportions on the flowability, consistency, water absorption, and mechanical properties of modified cement mortar were investigated. Also analyzed were the effects of MK content on the impermeability, frost resistance, and sulfate corrosion resistance of modified cement mortar when the w/b ratio was 0.31, according to the basic physical properties that were comprehensively considered. The internal microstructure of the modified cement mortar was analyzed by scanning electron microscopy. According to the results, 10 replacement levels were the optimum level of MK content in terms of strength and durability properties at a w/b ratio equaling 0.31. Compared with the control cement mortar, the modified cement mortar containing MK showed better development in strength and durability properties.
通讯机构：
[Haijun Lu; Mengyi Liu] S;School of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan 430023, China<&wdkj&>State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
作者机构：
[Zhang Rong-tang; Zhao Neng-hao] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.;[Yi Qing-lin; Song Kun] China Three Gorges Univ, Key Lab Geol Hazards Three Gorges Reservoir Area, Minist Educ, Yichang 443002, Peoples R China.
通讯机构：
[Kun Song] K;Key Laboratory of Geological Hazards on Three Gorges Reservoir Area (China Three Gorges University), Ministry of Education, Yichang, China
关键词：
Ring shear model;Discrete element method;THM coupling;Frictional heating;Thermal pressurization
摘要：
In this study, a new numerical model of ring shear tester for shear band soil of landslide was established. The special feature of this model is that it considers the mechanism of friction-induced thermal pressurization, which is potentially an important cause of high-speed catastrophic landslides. The key to the construction of this numerical ring shear model is to realize the THM (thermo-hydro-mechanical) dynamic coupling of soil particles, which includes the processes of frictional heating, thermal pressurization, and strength softening during shearing of solid particles. All of these are completed by using discrete element method. Based on this new model, the characteristics of shear stress change with shear displacement, as well as the variation of temperature and pore pressure in the specimen, are studied at shear rates of 0.055 m/s, 0.06 m/s, 0.109 m/s and 1.09 m/s, respectively. The results show that the peak strength and residual strength of specimen are significantly reduced when the mechanism of friction-induced thermal pressurization is considered. The greater the shear rate is, the higher the temperature as well as the pore pressure is. The effect of shear rate on the shear strength is bidirectional. The simulation results demonstrate that this model can effectively simulate the mechanism of friction-induced thermal pressurization of shear band soil during ring shear process, and the shear strength softening in the process. The new numerical ring shear model established in this study is of great significance for studying the dynamic mechanism of high-speed catastrophic landslides.
作者机构：
[Zhu, Jiebing; Xu, Dongdong; Wang, Bin] Minist Water Resources, Key Lab Geotech Mech & Engn, Changjiang River Sci Res Inst, Wuhan 430010, Peoples R China.;[Li, Cong] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.
通讯机构：
[Dongdong Xu] K;Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources, Changjiang River Scientific Research Institute, Wuhan 430010, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
crack propagation;freeze–thaw cycle;frost-heave force;physical model test;rock slope
作者机构：
[Wu, Jie; Li, Cong; Cheng, Fan; Zhang, Rongtang] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Peoples R China.;[Wu, Jie; Zhou, Yu] Natl Local Joint Engn Lab Bldg Hlth Monitoring &, Hefei 230601, Peoples R China.;[Zou, Chao] Guangdong Univ Technol, Sch Civil & Transportat Engn, Guangzhou 510006, Peoples R China.;[Huang, Shiping] South China Univ Technol, Sch Civil Engn & Transportat, Guangzhou 510640, Peoples R China.;[Zhou, Yu] Anhui Jianzhu Univ, Sch Civil Engn, Hefei 230601, Peoples R China.
通讯机构：
[Yu Zhou] N;National-Local Joint Engineering Laboratory of Building Health Monitoring and Disaster Prevention Technology, Hefei 230601, China<&wdkj&>School of Civil Engineering, Anhui Jianzhu University, Hefei 230601, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
model updating;Kriging model;swarm intelligence optimization;cable-stayed bridge
摘要：
Metakaolin (MK)-geopolymer has rapid coagulation at higher curing temperature, excellent durability, and mechanical properties. The aim of this research was to develop rapid repair materials of MK-based geopolymer cured at room temperature. In this study, portland cement was added to MK to prepare geopolymer. The influences of cement on the water requirement of normal consistency, setting time, bulk density, flowability, consistency, mechanical properties, and reaction mechanism of the geopolymer system were studied. The results showed that the consistency, flowability, bulk density, and mechanical properties of geopolymer were improved, and the setting time is prolonged by mixing a proper amount of cement into MK-geopolymer. When the cement content was 40 %, the strength of the geopolymer was the highest. Scanning electron microscopy and Fourier transform infrared analysis showed that the calcium silicate hydrate gel and sodium aluminosilicate hydrate gel structures overlapped each other and formed compact skeleton structure in the modified MK-geopolymer. The appropriate content of cement can give the geopolymer excellent performance under room temperature, which will contribute to the on-site construction of geopolymer.
期刊：
Journal of Cleaner Production,2022年363:132533 ISSN：0959-6526
通讯作者：
Zhipeng Li
作者机构：
[Gong, Jing] 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.;[Gong, Jing] Hunan Univ Sci & Technol, Sch Architecture & Art Design, Xiangtan 411201, Peoples R China.;[Yu, Lili] United Design Grp Co Ltd Xin Rui, Wuhan 430000, Peoples R China.;[Shi, Xianming; Li, Zhipeng] Washington State Univ, Natl Ctr Transportat Infrastructure Durabil & Life, Dept Civil & Environm Engn, POB 642910, Pullman, WA 99164 USA.
通讯机构：
[Zhipeng Li] N;National Center for Transportation Infrastructure Durability & Life-Extension, Department of Civil & Environmental Engineering, Washington State University, P.O. Box 642910, Pullman, WA, 99164-2910, United States
摘要：
This laboratory study explores the effects of mechanical activation on the properties of municipal solid waste incineration (MSWI) bottom ash (BA) in a cement hydration system. The experimental results showed that the mechanical activation effectively reduced the particle size of municipal solid waste incineration bottom ash (MSWIBA), increased its specific surface area by about 770%, 1674%, and 1990%, and improved the 28d compressive strength of bottom ash-cement paste samples by about 5%, 14%, and 8% after milling of 15min, 30min, and 45min, respectively. The scanning electron microscopy revealed that the microstructure of the 30min-milled bottom ash-cement sample was more homogenous than other samples, which likely accounted for the difference in compressive strength. X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis were employed to shed light on the process, products, and degree of hydration of bottom ash-cement pastes. In addition, the leachate toxicity of heavy metals was evaluated and the 30min-milled bottom ash-cement paste showed the best binding effect in reducing the leaching of heavy metals. This work demonstrates the great potential of using mechanical-activated MSWI bottom ash as a supplementary cementitious material with acceptable environmental footprint.
通讯机构：
[Jing Zhang] S;State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China<&wdkj&>School of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan, 430023, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
Recovery phosphorus (P) from P-contaminated wastewater is an efficient and environmentally friendly mean to prevent water pollution and alleviate the P shortage crisis. In this study, oyster shell as calcium sources and peanut shells as carbon sources (mass ratio 1:1) were used to prepare a novel Ca-modified biochar (OBC) via co-pyrolysis, and its potential application after P adsorption as a P biofertilizer for soil was also investigated. The results shown that OBC had a remarkable P adsorption capacity from wastewater in a wide range of pH 4-12. The maximum P adsorption capacity of OBC was about 168.2 mg/g with adsorbent dosage 1 g/L, which was about 27.6 times that of the unmodified biochar. The adsorption isotherm and kinetic data were better described by Langmuir isotherm model (R-2 > 0.986) and the pseudo second-order model (R-2 > 0.975), respectively. Characterization analysis of OBC before and after P adsorption by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and specific surface area and porosity analyzer (BET) indicated that the remarkable P adsorption capacity of OBC was mainly ascribed to chemical precipitation, electrostatic adsorption, and hydrogen bonding. Pot experiment results showed that OBC after P adsorption could significantly promote the germination and growth of Spinacia, which manifested that OBC after P adsorption exhibited a good ability to be reused as P fertilizer for soil.
期刊：
ACS Applied Energy Materials,2022年5(7):9109-9117 ISSN：2574-0962
通讯作者：
Fang, Yutang(ppytfang@scut.edu.cn)
作者机构：
[Wang, Shuangfeng; Gao, Xuenong; Zhang, Zhengguo; Liang, Xianghui; Fang, Yutang; Chen, Weicheng] South China Univ Technol, Key Lab Enhanced Heat Transfer & Energy Conservat, Minist Educ, Guangzhou 510640, Guangdong, Peoples R China.;[Fu, Wanwan] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Hubei, Peoples R China.
通讯机构：
[Yutang Fang] K;Key Laboratory of Enhanced Heat Transfer and Energy Conservation of the Ministry of Education, South China University of Technology, Guangzhou, Guangdong 510640, China
关键词：
In situ growth;phase change composites;photothermal conversion;thermal conductivity enhancement;thermal energy storage
作者机构：
[Dong, Jianhua; Huang, Guomin; Wu, Lifeng; Wu, Shaofei] Nanchang Inst Technol, Sch Hydraul & Ecol Engn, Nanchang 330099, Jiangxi, Peoples R China.;[Wu, Lifeng; Wang, Yicheng] China Inst Water Resources & Hydropower Res, State Key Lab Simulat & Regulat Water Cycle River, Beijing 100038, Peoples R China.;[Liu, Fa] Chinese Acad Sci, Inst Geog Sci & Sci & Nat Resources Res, Key Lab Water Cycle & Related Land Surface Proc, Beijing 100101, Peoples R China.;[Li, Sien] China Agr Univ, Ctr Agr Water Res China, Beijing 100083, Peoples R China.;[Cui, Yaokui] Peking Univ, Sch Earth & Space Sci, Inst RS & GIS, Beijing 100871, Peoples R China.
通讯机构：
[Lifeng Wu] S;State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China<&wdkj&>School of Hydraulic and Ecological Engineering, Nanchang Institute of Technology, Nanchang 330099, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
It has been reported that iron tailing powder (ITP) has the potential to partially replace cement to prepare ultra-high-performance concrete (UHPC). However, the reactivity of ITP particles in concrete largely depends on the curing method. This study investigates the effects of curing conditions on the mechanical and microstructural properties of UHPC containing ITP. To achieve this objective, three research tasks are conducted, including (1) preparing seven concrete formulations by introducing ITP; (2) characterizing their mechanical performance under different curing regimes; and (3) analyzing their microstructure by XRD patterns, FTIR analysis, and SEM observation. The experimental results show that there is an optimum ITP dosage (15%) for their application. The concrete with 15% ITP under standard curing obtains 94.3 MPa at 7 days, their early-age strength could be even further increased by similar to 30% (warm-water curing) and similar to 35% (steamed curing). The steam curing regime stimulates the activity of ITP and refines the microstructure. This study demonstrates the potential of replacing Portland cement with ITP in UHPC production.
摘要：
Cement-emulsified asphalt mixture (CEAM), a kind of cold mix asphalt mixture, has the advantages of energy conservation and emission reduction as well as easy construction. However, the performance of CEAM is not as good as hot mixed asphalt mixtures. Hence, in this study, two different fibers were adopted as the reinforcing phase to improve the comprehensive properties of CEAM. The results indicated that the addition proportion and curing time were crucial to fiber-reinforced cement-emulsified asphalt mixture (FRCEAM). The compressive strengths, water stability, and raveling resistances of FRCEAM preparations with polyester or brucite fibers (FRCEAM-PF and -BF, respectively) were enhanced significantly. FRCEAM-PF had the maximum flexural tensile strength and strain, which meant that its low-temperature performance was the best compared to FRCEAM-PF and CEAM. However, the contribution of PF to CEAM high-temperature stability was greater than that of BF. Fiber addition to CEAM not only enhanced the cycles of fatigue loading but also reduced sensitivity to changes in stress level. Furthermore, FRCEAM-BF durability was slightly better than that of FRCEAM-PF. SEM analysis indicated that fibers provided bridging and meshing effects. Although PF and BF showed different enhancement effects, both mixtures met the requirements for hot mixed asphalt mixtures.
作者：
Bao, M. D.;Zhu, J. G.;Geng, Z. Z.;Qian, B.;He, X.
期刊：
Soil Mechanics and Foundation Engineering,2021年58(1):34-40 ISSN：0038-0741
通讯作者：
J. G. Zhu
作者机构：
[Zhu, J. G.; Bao, M. D.] Hohai Univ, Jiangsu Res Ctr Geotech Engn Technol, Minist Educ Geomech & Embankment Engn, Key Lab, Nanjing, Peoples R China.;[Qian, B.; Geng, Z. Z.] Nanjing Hydraul Res Inst, Geotech Engn Dept, Nanjing, Peoples R China.;[He, X.] Wuhan Polytech Univ, Sch Engn & Architecture, Wuhan, Peoples R China.
通讯机构：
[J. G. Zhu] K;Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Jiangsu Research Center of Geotechnical Engineering Technology, Hohai University, Nanjing, China
摘要：
To clarify some of the inconsistencies in the research of equivalent diameter of PVDs, we constructed 3-D consolidation models of PVDs and sand drains using ABAQUS and compared models with and without sand drain resistance. When the sand drain resistance was included in the model, the equivalent diameters of the sand drains were 30, 65, 78, and 100 mm (for a 100-mm-wide, 4-mm-thick PVD) corresponding to PVD drainage depths (or soft soil layer thickness) of 2, 5, 8, and 10 m. Except for the depth of 2 m, the other results were higher than the values found in previous studies. The equivalent diameters increased with increasing consolidation depths. When the well resistance was ignored, the equivalent diameters were 20 mm for all the ground consolidation depths, which was less than the value in most previous research findings.
摘要：
The cumulative deformation of the clay foundation under long-term cyclic loading is severe, and various models have been developed for predicting and evaluating the cumulative plastic strain in clay under cyclic loading. Among them, the constitutive models and empirical models are most commonly used. However, they all have some limitations. In this paper, the dynamic deformation of different marine structured clay under different stress levels has been studied; then, a simplified method is established based on the combination of basic components to describe the cumulative deformation of structured clay under cyclic loading. The simplified calculation method can be applied to illustrate the development of both the stable strain-time curve and the metastable strain-time curve of clay under cyclic loading. Moreover, this model is also suitable for illustrating the development of the failure strain-time curve of clay, especially for those with brittle failure behavior of strongly structured clay. Therefore, this method can be employed to simulate different dynamic deformation characteristics of clay through a uniform formula with a few model parameters that have certain physical meanings. Besides, the critical dynamic stress can be approximately determined using the simplified method, and an analysis of dynamic deformation mechanisms of marine structured clay under long-term cyclic loading can be performed.
