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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1199-1213页

作者： DING Rui HE Yue LI Xingchen LI Han TIAN Hao WANG Hongen School of Materials Science and Engineering Jilin Jianzhu UniversityChangchun 130118China Ziyang Urban construction Investment Group co. LtdNanchong 637000China Shandong Taihe Urban construction Development co. Ltd.Jining 272000China

This paper studied the effects of different retarders on the performance of the"one-step"alkali-activated co.posite cementitious material(ACCM)which is co.posed of ground granulated blast slag(GGBS)and fly ash(FA),and analyzed its mechanical properties,hydration mechanism,and retardation *** effects of retarders on the hydration products,mechanical properties,and hydration kinetics of ACCM were investigated using XRD,SEM,FTIR,EDS,and thermoactive *** results showed that Na_(2)B_(4)O_(7)·10H_(2)O(B)delayed the exotherm during the alkali activation process and co.ld effectively delay the setting time of ACCM,but the mechanical properties were slightly *** setting time of ACCM increased with the increase in SG co.tent,but the mechanical properties of ACCM decreased with the increase in SG co.tent.C1_(2)H_(22)O_(11)(CHO)co.ld effectively delay the hydration reaction of ACCM and weakly enhanced the co.pressive strength.H_(3)PO_(4)(HP)at a co.centration of 0.05 mol/L had a certain effect on ACCM retardation,but HP at a co.centration of 0.07 and 0.09 mol/L had an effect of promoting the setting and hardening time of ACCM.

关键词： "one-step"alkali-activated co.posite cementitious materials solid activator hydration mechanism retarder retarding mechanism

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 co.position 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 co.fficient increase by 16.2%and 11.9%with respect to uncalcined red mud,reaching values of 0.826 and 0.974,*** with the co.trol group,the synergistic activation of calcined red mud with slag can increase the co.pressive and flexural strength of the mortar by 12.9%and 1.5%,reaching 8.7 and 62.4 MPa,***,the activity index and flexural co.fficient 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 microsco.ic properties

On the Preparation of Low-Temperature-Rise and Low-Shrinkage co.crete Based on Phosphorus Slag

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Fluid Dynamics & Materials Processing 2024年第4期20卷 803-814页

作者： Jianlong Jin Jingjing Ding Long Xiong Ming Bao Peng Zeng China construction Ready Mixed co.crete co. Ltd.Wuhan430000China

The effects of different co.tents of a MgO expansive agent and phosphorus slag on the mechanical properties,shrinkage behavior,and the heat of hydration of co.crete were *** slump flow,setting time,dry shrinkage,and hydration heat were used as sensitive parameters to assess the response of the co.sidered *** shown by the results,in general,with an increase in the phosphorus slag co.tent,the hydration heat of co.crete decreases for all ages,but the early strength displays a downward trend and the dry shrinkage rate *** 90-d strength and dry shrinkage of co.crete co.ld be improved with a phosphorus residue co.tent between 0%-20%,with the best performances in terms of mechanical properties and shrinkage characteristics being achieved for a co.tent of 20 kg/m^(3).On the basis of these results,it can be co.cluded that appropriate amounts of phosphorus slag and MgO expansive agent can be used to improve the co.pressive strength of co.crete in the later stage by reducing the hydration heat and dry shrinkage rate,respectively.

关键词： Phosphorus slag MgO expansion agent mass co.crete hydration heat

Hydration Behavior and Cementitious Properties of Calcium Carbonate-aluminate Minerals co.posite

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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 co.lege 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 co.posite system of calcium carbonate and aluminate minerals is studied by measuring the co.ponent of hydration products, the hydration heat, setting time and co.pressive *** results prove that the co.posite 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

Investigation of FRP and SFRC Technologies for Efficient Tunnel Reinforcement Using the co.esive Zone Model

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Structural Durability & Health Monitoring 2024年第2期18卷 161-179页

作者： Gang Niu Zhaoyang Jin Wei Zhang Yiqun Huang China co.munications construction Investment Development co. Ltd.Fuzhou350000China Rail Transit Branch of China co.munications construction co. Ltd.Beijing101317China School of Civil Engineering Fujian University of TechnologyFuzhou350118China

Amid urbanization and the co.tinuous expansion of transportation networks,the necessity for tunnel construction and maintenance has beco.e *** this need requires the investigation of efficient,eco.omical,and robust tunnel reinforcement *** paper explores fiber reinforced polymer(FRP)and steel fiber reinforced co.crete(SFRC)technologies,which have emerged as viable solutions for enhancing tunnel *** is celebrated for its lightweight and high-strength attributes,effectively augmenting load-bearing capacity and seismic resistance,while SFRC’s notable crack resistance and longevity potentially enhance the performance of tunnel ***,current research predominantly focuses on experimental analysis,lacking co.prehensive theoretical *** bridge this gap,the co.esive zone model(CZM),which utilizes co.esive elements to characterize the potential fracture surfaces of co.crete/SFRC,the rebar-co.crete interface,and the FRP-co.crete interface,was employed.A modeling approach was subsequently proposed to co.struct a tunnel segment model reinforced with either SFRC or ***,the co.responding mixed-mode co.stitutive models,co.sidering interfacial friction,were integrated into the proposed *** validation and numerical simulations co.roborated the accuracy of the proposed ***,this study examined the reinforcement design of tunnel *** a numerical evaluation,the effectiveness of innovative reinforcement schemes,such as substituting co.crete with SFRC and externally bonding FRP sheets,was assessed utilizing a case study from the Fuzhou Metro Shield Tunnel construction Project.

关键词： Tunnel segment FRP SFRC co.esive zone model co.stitutive model fracture process

A new neural-network-based method for structural damage identification in single-layer reticulated shells

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 104-121页

作者： Jindong ZHANG Xiaonong GUO Shaohan ZONG Yujian ZHANG co.lege of Civil Engineering Tongji UniversityShanghai 200092China China construction Eighth Engineering Division co. Ltd.Shanghai 200135China

Single-layer reticulated shells(SLRSs)find widespread application in the roofs of crucial public structures,such as gymnasiums and exhibition *** this paper,a new neural-network-based method for structural damage identification in SLRSs is ***,a damage vector index,NDL,that is related only to the damage localization,is proposed for SLRSs,and a damage data set is co.structed from NDL *** the basis of visualization of the NDL damage data set,the structural damaged region locations are identified using co.volutional neural networks(CNNs).By cross-dividing the damaged region locations and using parallel CNNs for each regional location,the damaged region locations can be quickly and efficiently identified and the undamaged region locations can be ***,a damage vector index,DS,that is related to the damage location and damage degree,is proposed for *** on the damaged region identified previously,a fully co.nected neural network(FCNN)is co.structed to identify the location and damage degree of *** effectiveness and reliability of the proposed method are verified by co.sidering a numerical case of a spherical *** calculation results showed that the proposed method can quickly eliminate candidate locations of potential damaged region locations and precisely determine the location and damage degree of members.

关键词： single-layer reticulated shell damage identification neural network co.volutional neural network cross-partitioning method

Assessment of the Influence of Tunnel Settlement on Operational Performance of Subway Vehicles

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Structural Durability & Health Monitoring 2024年第1期18卷 55-71页

作者： Gang Niu Guangwei Zhang Zhaoyang Jin Wei Zhang Xiang Liu China co.munications construction Rail Transit Subsidiary Beijing100000China China co.munications construction Strait construction Investment Development co. Ltd.Fuzhou350000China School of Civil Engineering Fujian University of TechnologyFuzhou350118China

In the realm of subway shield tunnel operations,the impact of tunnel settlement on the operational performance of subway vehicles is a crucial *** study introduces an advanced analytical model to investigate rail geometric deformations caused by settlement within a vehicle-track-tunnel co.pled *** model integrates the geometric deformations of the track,attributed to settlement,as track irregularities.A novel“cyclic model”algorithm was employed to enhance co.putational efficiency without co.promising on precision,a claim that was rigorously *** model’s capability extends to analyzing the time-history responses of vehicles traversing settlement-affected *** research primarily focuses on how settlement wavelength,amplitude,and vehicle speed influence operational *** findings indicate that an increase in settlement wavelength can improve vehicle performance,whereas a rise in amplitude can degrade *** study also establishes settlement thresholds,based on vehicle operation co.fort and *** insights are pivotal for maintaining and enhancing the safety and efficiency of subway systems,providing a valuable framework for urban infrastructure management and long-term maintenance strategies in metropolitan transit systems.

关键词： Settlement running performance subway tunnel dynamic analysis track irregularity threshold

Research on Sleeve Grouting Density Detection Based on the Impact Echo Method

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Structural Durability & Health Monitoring 2024年第2期18卷 143-159页

作者： Pu Zhang Yingjun Li Xinyu Zhu Shizhan Xu Pinwu Guan Wei Liu Yanwei Guo Haibo Wang School of Civil Engineering Zhengzhou UniversityZhengzhou450000China Xixi Expressway construction co. Ltd.Nanyang474450China

Grouting defects are an inherent challenge in construction practices,exerting a co.siderable impact on the operational structural integrity of *** investigation employed the impact-echo technique for the detection of grouting anomalies within co.nections,enhancing its precision through the integration of wavelet packet energy principles for damage identification purposes.A series of grouting co.pleteness assessments were meticulously co.ducted,taking into acco.nt variables such as the divergent material properties of the sleeves and the co.figuration of adjacent *** findings revealed that:(i)the energy distribution for the highstrength co.crete co.ort predominantly occupied the frequency bands 42,44,45,and 47,whereas for other groups,it was co.centrated within the 37 to 40 frequency band;(ii)the delineation of empty sleeves was effectively discernible by examining the wavelet packet energy ratios across the spectrum of frequencies,albeit distinguishing between sleeves with 50%and full grouting density proved challenging;and(iii)the wavelet packet energy analysis yielded variable detection outco.es co.tingent on the material attributes of the sleeves,demonstrating heightened sensitivity when applied to ultrahigh-performance co.crete matrices and GFRP-reinforced steel bars.

关键词： Prefabricated building steel grouting sleeve impact echo method wavelet packet energy grouted defect

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 co.sulting 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 co.t *** 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 inco.porating co.posite wear mechanisms and load estimation techniques,showcasing superior prediction accuracy co.pared to single-mechanism ***,the hybrid model innovatively inco.porates 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 co.pared 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 co.ditions 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

Exploring plant adaptation strategies to phosphorus limitation induced by nitrogen addition:foliar phosphorus allocation and root functional traits analysis in two dominant subalpine tree species

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Journal of Plant Eco.ogy 2024年第4期17卷 154-166页

作者： Yan Su Yongfeng Tang Yi Hu Meiyu Liu Xuyang Lu Baoli Duan Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China Sichuan Eco.ogical Environment construction Engineering Supervision co. Ltd.Chengdu 610084China

Plants adapt to the limitation of soil phosphorus(P)induced by nitrogen(N)deposition through a co.plex interaction of various root and leaf functional *** this study,a pot experiment was co.ducted to explore the effects of different levels of N addition(co.trol,low N[LN]:25 kg N ha^(-1) yr^(-1),high N[HN]:50 kg N ha^(-1) yr^(-1))on tree growth,leaf nutrient co.tent,foliar P fractions and root characteristics of two dominant tree species,the pioneer species Salix rehderiana Schneid and the climax species Abies fabri(Mast.)Craib,in a subalpine forest in southwestern *** results demonstrated that LN addition had a minimal impact on leaf N and P ***,HN addition significantly decreased the leaf P co.tent in both *** rehderiana exhibited more pronounced increases in specific root length and specific root area under P deficiency triggered by HN addition when co.pared with *** co.trast,*** showed weaker morphological responses to N addition but had a higher proportion of foliar P to metabolic P,as well as higher root exudates rate and root phosphatase activity in response to HN *** fabri employs a synergistic approach by allocating a greater amount of leaf P to metabolite P and extracting P from the soil through P-mobilizing exudates and root phosphatase activity,while *** exhibits higher flexibility in modifying its root morphology in response to P limitation induced by HN *** study provides insights into subalpine tree species adaptation to N-induced P limitation,emphasizing its significance for guiding forest management and co.servation in the co.text of global climate change.

关键词： N deposition root functional traits root morphology root exudation P-scavenging strategy