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Analysis of Calcined Red Mud Properties and Related Mortar Performances

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Fluid Dynamics & Materials Processing 2024年第5期20卷 901-913页

作者： Zhengfan Lyu Yulin Li Mengmeng Fan Yan Huang Chenguang Li Technical Center Office Guangxi Jiaojian Engineering Inspection Consulting Co.Ltd.Nanning530001China Technical Center Office Guangxi Road Construction Engineering Group Co.Ltd.Nanning530001China Nanning Road construction Technology and Road construction Materials Engineering Technology Research Centre Guangxi Road Construction Engineering Group Co.Ltd.Nanning530001China

Red mud(RM)is a low-activity industrial solid waste,and its utilization as a resource is currently a hot *** this study,the micro characteristics of red mud at different calcination temperatures were analyzed using X-ray diffraction and scanning electron *** performance of calcined red mud was determined through mortar strength *** indicate that high-temperature calcination can change the mineral composition and microstructure of red mud,and increase the surface roughness and specific surface *** the optimal temperature of 700°C,the addition of calcined red mud still leads to a decrease in mortar strength,but its activity index and flexural coefficient increase by 16.2%and 11.9%with respect to uncalcined red mud,reaching values of 0.826 and 0.974,*** with the control group,the synergistic activation of calcined red mud with slag can increase the compressive and flexural strength of the mortar by 12.9%and 1.5%,reaching 8.7 and 62.4 MPa,***,the activity index and flexural coefficient of the calcined RM and GGBS(Ground Granulated Blast furnace Slag)mixtures also increase to 1.015 and 1.130,respectively.

关键词： Red mud slag thermal activation synergistic activation mortar test microscopic properties

Hydration Behavior and Cementitious Properties of Calcium Carbonate-aluminate Minerals composite

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 126-133页

作者：王冲周帅 ZOU Luyao LIU Jiawen ZHENG Yalin college of Materials Science and Engineering Chongqing UniversityChongqing 400045China China West construction group co. Ltd.Chengdu 610015China

The purpose of this research is to investigate the hydration behavior and cementitious properties of the mixture of calcium carbonate and aluminate, and to explore whether it can be adopted as a new low-carbon cementitious material. The composite system of calcium carbonate and aluminate minerals is studied by measuring the component of hydration products, the hydration heat, setting time and compressive *** results prove that the composite system has certain cementitious properties and is feasible to prepare new low-carbon cement.

关键词： limestone hydrated calcium carboaluminate cementitious properties mechanical properties

Structural effects of sulfonamides on the proliferation dynamics of sulfonamide resistance genes in the sequencing batch reactors and the mechanism

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Journal of Environmental Sciences 2024年第1期135卷 161-173页

作者： Ligui Wu Mingyu Wang Lingling Rong Wenbiao Wang Linwei Chen Qiaofeng Wu Haoyu Sun Xiangfeng Huang Xiaoming Zou college of Environmental Science and Engineering Tongji UniversityShanghai 200092China School of Life Science Jinggangshan UniversityJi’an 343009China Key Laboratory of Organic compound Pollution control Engineering(MOE) School of Environmental and Chemical EngineeringShanghai UniversityShanghai 200444China Fuzhou Urban and Rural construction group co.ltd. Fuzhou 350007China

Antibiotic resistance genes(ARGs)can be easily promoted by antibiotics,however,the structural effects of antibiotics on the proliferation of ARGs dynamic and the associated mechanisms remain obscure in,especially,activated sludge sequencing batch *** the present study,the effects of 9 sulfonamides(SAs)with different structures on the proliferation dynamic of sulfonamide resistance genes(Suls)in the activated sludge sequencing batch reactors and the corresponding mechanisms were determined(30 days),and the results showed that the largest proliferation value(ΔA^(R))of Suls dynamic for SAs(sulfachloropyridazine)was approximately 2.9 times than that of the smallest one(sulfadiazine).The proliferation of Suls was significantly related to the structural features(minHBint6,SssNH,SHBd and SpMax2_Bhm)that represent the biological activity of *** interpret the phenomenon,a mechanistic model was developed and the results indicated that the biodegradation of SAs(T_(1/2))rather than conjugative transfer frequency or mutation frequency tends to be the key process for affecting Suls proliferation.T_(1/2)was proved to be dependent on the interactions between SAs and receptors(E_(binding)),the cleavage mode(bond dissociation energy),and the site of nucleophilic ***,the metagenomic analysis showed that SAs posed significant effect on antibiotic resistome and Tnp31 played a vital role in the proliferation of ***,our findings provide important insight into a theoretical basis for understanding the structural effects of SAs on the proliferation of ARGs in SBR systems.

关键词： Activated sludge Sulfonamides Suls Proliferation Mechanism

Research on the design method for uniform wear of shield cutters in sand-pebble strata

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Deep Underground Science and Engineering 2024年第2期3卷 216-230页

作者： Jinxun Zhang Bo Li Guihe Wang Yusheng Jiang Hua Jiang Minglun Yin Zhengyang Sun Beijing Urban construction group co. Ltd.BeijingChina China University of Geosciences BeijingChina China University of Mining and Technology BeijingChina

During shield tunneling in highly abrasive formations such as sand–pebble strata,nonuniform wear of shield cutters is inevitable due to the different cutting *** downtimes and cutter replacements have become major obstacles to long-distance shield driving in sand–pebble *** on the cutter wear characteristics in sand–pebble strata in Beijing,a design methodology for the cutterhead and cutters was established in this study to achieve uniform wear of all cutters by the principle of frictional *** applicability of the design method was verified through three-dimensional simulations using the engineering discrete element *** results show that uniform wear of all cutters on the cutterhead could be achieved by installing different numbers of cutters on each trajectory radius and designing a curved spoke with a certain arch height according to the shield *** the uniform wear scheme,the cutter wear coefficient is greatly reduced,and the largest shield driving distance is increased by approximately 47%over the engineering *** research results indicate that the problem of nonuniform cutter wear in shield excavation could be overcome,thereby providing guiding significance for theoretical innovation and construction of long-distance shield excavation in highly abrasive strata.

关键词： cutter wear EDEM model long-distance shield driving sand-pebble stratum shield tunnel uniform wear design method

Regression Method for Rail Fastener Tightness Based on Center-Line Projection Distance Feature and Neural Network

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 356-371页

作者： Yuanhang Wang Duxin Liu Sheng Guo Yifan Wu Jing Liu Wei Li Hongjie Wang Robotics Research Center School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China China construction Industrial&Energy Engineering group co. Ltd.Nanjing 210023China

In the railway system,fasteners have the functions of damping,maintaining the track distance,and adjusting the track ***,routine maintenance and inspection of fasteners are important to ensure the safe operation of track ***,assessment methods for fastener tightness include manual observation,acoustic wave detection,and image *** are limitations such as low accuracy and efficiency,easy interference and misjudgment,and a lack of accurate,stable,and fast detection *** at the small deformation characteristics and large elastic change of fasteners from full loosening to full tightening,this study proposes high-precision surface-structured light technology for fastener detection and fastener deformation feature extraction based on the center-line projection distance and a fastener tightness regression method based on neural ***,the method uses a 3D camera to obtain a fastener point cloud and then segments the elastic rod area based on the iterative closest point algorithm *** component analysis is used to calculate the normal vector of the segmented elastic rod surface and extract the point on the centerline of the elastic *** point is projected onto the upper surface of the bolt to calculate the projection ***,the mapping relationship between the projection distance sequence and fastener tightness is established,and the influence of each parameter on the fastener tightness prediction is ***,by setting up a fastener detection scene in the track experimental base,collecting data,and completing the algorithm verification,the results showed that the deviation between the fastener tightness regression value obtained after the algorithm processing and the actual measured value RMSE was 0.2196 mm,which significantly improved the effect compared with other tightness detection methods,and realized an effective fastener tightness regression.

关键词： Railway system Fasteners Tightness inspection Neural network regression 3D point cloud processing

Review on frost resistance and anti-clogging of pervious concrete

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 481-496页

作者： Zhuo Wang Zhichen Liu Feng Zeng Kun He Shuaicheng Guo China Railway construction group co. Ltd.Beijing 100040China State Key Laboratory of Bridge Safety and Resilience College of Civil EngineeringHunan UniversityChangsha 410082China

Pervious concrete is a special type of concrete that is of high porosity and contains no or a small amount of fine aggregate,and it is an important basic material for sponge city *** presence of a large number of connected pores inside pervious concrete leads to a marked difference in durability failure mechanism compared with that of ordinary *** this study,the frost resistance and anti-clogging of pervious concrete were introduced in detail,and the methods to improve their performance were summarized *** cracking pattern of pervious concrete is influenced by geometric characteristics and three-dimensional morphological features of pores,resulting in its crack generation,development,and geometry being significantly different from those of ordinary concrete,thus leading to different freeze-thaw cycle *** addition,due to its different pore structure compared to ordinary concrete,three types of clogging mechanisms,affecting the long-term permeability of pervious concrete were elaborated systematically(i.e.,physical clogging,biological clogging,and chemical clogging).And the ways to improve the anti-clogging of pervious concrete are systematically presented from multiple ***,in order to broaden the engineering applications of pervious concrete,some research proposals are presented in this study.

关键词： Pervious concrete connected pore Frost resistance Clogging mechanism

Enhanced wear prediction of tunnel boring machine disc cutters for accurate remaining useful life estimation using a hybrid model

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 642-662页

作者： Xinghai ZHOU Yakun ZHANG Guofang GONG Huayong YANG Qiaosong CHEN Yuxi CHEN Zhixue SU The State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou 310027China Guangzhou Rail Transit construction Engineering consulting co. Ltd.Guangzhou 510000China China Railway Engineering Equipment group co. Ltd.Zhengzhou 450016China

In tunnel construction with tunnel boring machines(TBMs),accurate prediction of the remaining useful life(RUL)of disc cutters is critical for timely maintenance and replacement to avoid delays and cost *** paper introduces a novel hybrid model,integrating fundamental and data-driven approaches,to enhance wear prediction of TBM disc cutters and enable accurate RUL *** fundamental model is improved by incorporating composite wear mechanisms and load estimation techniques,showcasing superior prediction accuracy compared to single-mechanism ***,the hybrid model innovatively incorporates a data-driven supplementary residual term into the improved fundamental model,leading to a high-performance wear prediction *** actual field data from a highway tunnel project in Shenzhen,the performance of the hybrid model is rigorously tested and compared with pure fundamental and data-driven *** hybrid model outperforms the other models,achieving the highest accuracy in predicting TBM disc cutter wear(mean absolute error(MAE)=0.53,root mean square error(RMSE)=0.64).Furthermore,this study thoroughly analyzes the hybrid model’s generalization capability,revealing significant impacts of geological conditions on prediction *** model’s generalization capability is also improved by expanding and updating the data *** RUL estimation results provided by the hybrid model are straightforward and effective,making it a valuable tool by which construction staff can monitor TBM disc cutters.

关键词： tunnel boring machine disc cutter wear prediction remaining useful life field data hybrid model

Theory,technology and application of grouted bolting in soft rock roadways of deep coal mines

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1463-1479页

作者： Hongpu Kang Jianwei Yang Pengfei Jiang Fuqiang Gao Wenzhou Li Jiafeng Li Huiyuan Chen coal Mining Research Institute China Coal Technology and Engineering Group Co.Ltd.Beijing 100013China coal Mining Branch China Coal Research InstituteBeijing 100013China State Key Laboratory of Intelligent Mining and Strata control Beijing 100013China

The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured *** has been extensively applied in numerous deep mining areas characterized by soft rock roadways,where it has demonstrated remarkable control *** article systematically explores the evolution of grouted bolting,covering its theoretical foundations,design methods,materials,construction processes,monitoring measures,and methods for assessing its *** overview encompassed several key elements,delving into anchoring theory and grouting reinforcement *** new principle of high pretensioned high-pressure splitting grouted bolting collaborative active control is introduced.A fresh method for dynamic information design is also *** discussion touches on both conventional grouting rock bolts and cable bolts,as well as innovative grouted rock bolts and cables characterized by their high pretension,strength,and sealing hole *** examination of the merits and demerits of standard inorganic and organic grouting materials versus the new inorganic–organic composite materials,including their specific application conditions,was ***,the article presents various methods and instruments to assess the support effect of grouting rock bolts,cable bolts,and grouting ***,it provides a foundation for understanding the factors influencing decisions on grouted bolting timing,the sequence of grouting,the pressure applied,the volume of grout used,and the strategic arrangement of grouted rock bolts and cable *** application of the high pretensioned high-pressure splitting grouted bolting collaborative control technology in a typical kilometer-deep soft rock mine in China—the soft coal seam and soft rock roadway in the Kouzidong coal mine,Huainan coal mining area,was ***,the existing problems in grouted bolting control

关键词： deep coal mine soft rock roadway grouted bolting rock bolt and cable grouting material high-pressure splitting grouting collaborative control technology

Predicting torsional capacity of reinforced concrete members by data-driven machine learning models

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Frontiers of Structural and Civil Engineering 2024年第3期18卷 444-460页

作者： Shenggang CHEN congcong CHEN Shengyuan LI Junying GUO Quanquan GUO Chaolai LI School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou 211116China Jiangsu Key Laboratory Environmental Impact and Structural Safety in Engineering China University of Mining and TechnologyXuzhou 211116China China Nuclear Power Design co.ltd. Shenzhen 518031China School of transportation and science engineering Beihang UniversityBeijing 100191China China construction First group corporation Limited Beijing 100161China

Due to the complicated three-dimensional behaviors and testing limitations of reinforced concrete(RC)members in torsion,torsional mechanism exploration and torsional performance prediction have always been *** the present paper,several machine learning models were applied to predict the torsional capacity of RC *** results of a total of 287 torsional specimens were collected through an overall literature *** of extreme gradient boosting machine(XGBM),random forest regression,back propagation artificial neural network and support vector machine,were trained and tested by 10-fold cross-validation *** performances of proposed machine learning models were evaluated and compared,both with each other and with the calculated results of existing design codes,i.e.,GB 50010,ACI 318-19,and Eurocode *** results demonstrated that better predictive performance was achieved by machine learning models,whereas GB 50010 slightly overestimated the torsional capacity,and ACI 318-19 and Eurocode 2 underestimated it,especially in the case of ACI *** XGBM model gave the most favorable predictions with R^(2)=0.999,RMSE=1.386,MAE=0.86,andλ=***,strength of concrete was the most sensitive input parameters affecting the reliability of the predictive model,followed by transverse-to-longitudinal reinforcement ratio and total reinforcement ratio.

关键词： RC members torsional capacity machine learning models design codes