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A review on adhesion behavior of chip seal pavement and aggregate

Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 441-466页

作者： Yuming Zhou Zhuyi Peng Jinyu Wang Jianguo Wei Hao Liu Di Wang Jinming Li Key Laboratory of Road Structure and Material of Ministry of Transport (Changsha) Changsha University of Science and Technology School of Traffic and Transportation Engineering Changsha University of Science and Technology Wuhan Huike Testing Co. Ltd. Department of Civil Engineering University of Ottawa CCCC Infrastructure Maintenance Group Co. Ltd.

Chip seal is widely used for preventive maintenance to mitigate pavement deterioration,but it is prone to aggregate loss during pavement service. To further promote the development and application of chip seals in road engineering in China, the research progress of the adhesion behavior of aggregate and binder in chip seals was reviewed in this paper,focusing on the adhesion mechanism of emulsified asphalt and alkaline aggregate. The Influencing factors and evaluation methodology of chip seals' aggregate adhesion behavior were also discussed. The results demonstrate that the adhesion process between emulsified asphalt and alkaline aggregate is divided into three processes including infiltration,demulsification, and cluster, which is more complicated when compared to hot asphalt.When designing a chip seal, not only the characteristics of single material should be paid attention to, but also the combination of binder and aggregate matters a lot. To form good adhesion between aggregate and asphalt binder, various influencing factors such as material selection, design method, and construction technical index should be considered comprehensively in the whole design, construction, and operation process. Three methods for evaluating adhesion behavior are summarized, including macroscopic adhesion performance tests, image analysis technology, and model prediction. It is not objective to evaluate the aggregate adhesion behavior of chip seal only by a single evaluation method.A comprehensive evaluation based on the micro-macro multi-scale method should be considered in the future.

关键词： Chip seal Adhesion behavior Asphalt binder aggregate

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Accumulation and relationship of metals in different soil aggregate fractions along soil profiles

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Journal of Environmental Sciences 2022年第5期34卷 47-54页

作者： Qian Shen Mengjie Wu Mingkui Zhang Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition College of Environmental&Resource SciencesZhejiang UniversityHangzhou 310058China

Different aggregates vary in their ability to retain or adsorb metals in soil.Five soil profiles were sampled from different soil horizons and grouped,and the concentrations of Al,Mg,Ca,Fe,Mn,Cd,Cu and Pb were determined in six sizes of aggregates(>2,2-1,1-0.6,0.6-0.25,0.25-0.053,aggregates from topsoil.In addition,ASI and SSI were positively correlated(r=0.569,paggregates could contribute to the structural stability of bulk soil.Moreover,accumulation factors(AF),principal component analysis(PCA)and Pearson's correlation co-efficients were used for metal element assessment.The results indicated that SOM was not a key factor affecting the accumulation of Ca,Mg,Al,Fe,Mn,Pb,Cd and Cu in soil aggre-gates.In general,AF values for metal elements in microaggregates(aggregates.The PCA and Pearson's correlation coefficients indicated that soil parent materials primarily controlled the distribution of Al,Ca,Fe,Mg and Mn,while materials derived from technogenic sources have important impacts on the distribution of Cd,Cu and Pb in soil aggregates along the soil profile.

关键词： Soil profile aggregate Structural stability index(SSI) aggregate stability index(ASI) Metals Accumulation factor(AF)

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Substitution of aggregates in Concrete and Mortar with Coltan Mining Waste: Mechanical, Environmental, and Economic Impact Case Study

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Journal of Minerals and Materials Characterization and Engineering 2024年第2期12卷 139-163页

作者： Alinabiwe Nyamuhanga Ally Élodie Ruffine Zang Masika Muhiwa Grâce Manjia Marcelline Blanche Ursula Joyce Merveilles Pettang Nana Ngapgue François Bella Nabil Chrispin Pettang Laboratory Engineering Civil and Mechanics Doctoral Research Unit for Engineering and Applications University of Yaound&#233 I Yaound&#233 Cameroon Department of Civil Engineering Faculty of Applied Sciences and Technologies Free University of Great Lakes Countries (ULPGL) Goma DRC Department of Civil Engineering National Advanced School of Engineering of Yaoundé University of Yaoundé I Yaoundé Cameroon Department of Civil Engineering Fotso Victor University Institute of Technology University of Dschang Bandjoun Cameroon FIMAS Laboratory Faculty of Technologies Tahri Mohamed University Bechar Algeria

The mining process involves drilling and excavation, resulting in the production of waste rock and tailings. The waste materials are then removed and stored in designated areas. This study aims to evaluate the mechanical strength and the environmental and economic impact of using Coltan Mining Waste (CMW) as a substitute for aggregates in concrete and mortar production. To achieve this, the CMW needs to be characterised. The Dreux Gorisse method was primarily used to produce concrete with a strength of 20 MPa at 28 days. The mortars, on the other hand, were formulated according to the NF P 18-452 standard. The environmental impact of using CMW as substitutes for natural aggregates in the production of concrete and mortar was analysed using SimaPro software. The results showed that mortars and concrete made with CMW have comparable compressive strengths to the reference mortar and concrete;reduce the negative impact on ecosystem quality, human health, resources, and climate change. It has also been shown that the substitution of aggregates by CMW reduces the cost of concrete and mortar as a function of the distance from the aggregate footprint.

关键词： aggregate Coltan Mining Waste Concrete Mortar Mechanical Strength Life Cycle Analysis

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China's Path Towards Consumption-Led Growth in the New Era

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China Forex 2024年第1期 20-27页

作者： WANG Wei WANG Nian Development Research Center of the State Council

Consumption is the mainstay of an economy's aggregate demand,the fundamental driver of large economies,and a cornerstone of a secure,wellmanaged,and resilient economic system.China's new strategic priority is to effec... 详细信息

关键词： Consumption corners aggregate

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From bud to blossom:The incredible journey of aggregate

Aggregate

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aggregate 2023年第6期4卷 1-2页

作者： Ben Zhong Tang School of Science and Engineering The Chinese University of Hong KongShenzhenGuangdongP.R.China

The days are long,but the years are short.This quote perfectly encapsulates my feelings as we mark the third anniversary of aggregate.Over the past 3 years,Aggre-gate has been a steadfast companion to scientists,growing together with them in the field of research on aggregate science.On June 28,2023,Clarivate Analytics unveiled Jour-nal Citation Reports(JCR)2023 and aggregate received its first Journal Impact Factor(JIF)of 18.8.This is a great milestone in the development of aggregate.I am thrilled to witness that aggregate has made further progress this year in terms of both the quantity and quality of published papers.

关键词： aggregate Impact aggregate

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aggregate modeling and analysis of air conditioning load using coupled Fokker–Planck equations

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Journal of Modern Power Systems and Clean Energy 2018年第6期6卷 1277-1290页

作者： Dingyi CHENG Wen ZHANG Yutian LIU Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University

Demand response has gained significant attention recently with the increasing penetration of renewable energy sources in power systems. Air conditioning loads are typical thermostatically controlled loads which can play an active role in ancillary services by regulating their aggregated power consumption. The aggregation of air conditioners is essential to the control of air conditioning loads. In this paper, linear state equations are proposed to aggregate air conditioning loads by solving coupled Fokker–Planck equations(CFPEs) using the finite difference method. By analyzing the numerical stability and convergence of the difference scheme, the grid spacings, including temperature step and time step, are properly determined according to the maximal principle. Stationary solutions of the CFPEs are obtained by analytical and numerical methods. Furthermore, a classification method using dimension reduction is proposed to deal with the problem of heterogeneous parameters and interval estimation is applied to describe the stochastic behavior of air conditioning loads. The simulation results verify the effectiveness of the proposed methods.

关键词： aggregate model Air conditioner Coupled Fokker–Planck equation Grid spacing selection Heterogeneous Interval estimation Linear state equation Stationary solution

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Evaluation of the mechanical degradation of carbonate aggregate by rock strength tests

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第1期11卷 121-134页

作者： Mojtaba Kamani Rassoul Ajalloeian Department of Ceology University of Isfahan

aggregate degradation(AD) is one of the major reasons accounting for failure of aggregate materials, and the mechanical degradation of aggregate materials can be determined by different test methods. This process basically requires many aggregate samples and special instruments, and thus is time-consuming.The main purpose of this research is to evaluate the possibility of estimating the AD characteristics using rock strength tests and to investigate the relationships between AD properties and rock strength tests.For understanding the relationships, two common rock strength tests are employed, i.e. unconfined compressive strength(UCS) and point load index(PLI) tests. In the tests, the AD properties of 40 kinds of carbonate aggregates sampled from Iran were studied. The AD properties were determined by Los Angeles abrasion value(LAAV), aggregate impact value(AIV) and aggregate crushing value(ACV). Also,the samples are classified according to the strength and rock types, and the effect of this classification is investigated based on the relationship between rock strengths and AD properties. The results indicate that the PLI is better than UCS for evaluation of AD properties. Among rock strength tests, PLI has a closer relationship with AIV(R^2 = 0.832). Also, UCS has relative larger effects on the ACV(R^2 = 0.812) under the same loading condition. The weakest correlation occurs between LAAV and UCS(R^2 = 0.679). In view of the rational AD properties in the predictive procedure, it is possible to predict AD properties based on the strength tests and rock types. The results also show that the prediction of AD properties using rock strength test based on rock types yields better correlations than that using unclassified samples. The classification based on rock types can extrapolate the different relationships of AD prediction from rock strength tests. The results in this context could be used for preliminarily selecting proper rock aggregates with a limit of allowable AD tests for practical applications by PLI.

关键词： aggregate degradation Unconfined compressive strength Point load index Carbonate aggregates

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Behaviors of recycled aggregate concrete-filled steel tubular columns under eccentric loadings

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Frontiers of Structural and Civil Engineering 2019年第3期13卷 628-639页

作者： Vivian W.Y.TAM Jianzhuang XIAO Sheng LIU Zixuan CHEN Department of Structural Engineering Tongji UniversityShanghai 200092China University of Western Sydney School of ComputingEngineering and Mathematics and Institute for Infrastructure EngineeringLocked Bag 1797PenrithNSW 2751Australia

The paper investigates the behaviors of recycled aggregate concrete-filled steel tubular(RACFST)columns under eccentric loadings with the incorporation of expansive agents.A total of 16 RACFST columns were tested in this study.The main parameters varied in this study are recycled coarse aggregate replacement percentages(0%,30%,50%,70%,and 100%),expansive agent dosages(0%,8%,and 15%)and an eccentric distance of compressive load from the center of the column(0 and 40 mm).Experimental results showed that the ultimate stresses of RACFST columns decreased with increasing recycled coarse aggregate replacement percentages but appropriate expansive agent dosages can reduce the decrement;the incorporation of expansive agent decreased the ultimate stresses of RACFST columns but an appropriate dosage can increase the deformation ability.The recycled coarse aggregate replacement percentages have limited influence on the ultimate stresses of the RACFST columns and has more effect than that of the normal aggregate concretesteel tubular columns.

关键词： concrete filled steel tubes recycled aggregate concrete columns expansive agent eccentric load

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Punching shear behavior of recycled aggregate concrete slabs with and without steel fibres

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Frontiers of Structural and Civil Engineering 2019年第3期13卷 725-740页

作者： Jianzhuang XIAO Wan WANG Zhengjiu ZHOU Mathews M.TAWANA Department of Structural Engineering Tongji UniversityShanghai 200092China

A study on the punching shear behavior of 8 slabs with recycled aggregate concrete(RAC)was carried out.The two main factors considered were the recycled coarse aggregate(RCA)replacement percentage and the steel fibre volumetric ratio.The failure pattern,load-displacement curves,energy consumption,and the punching shear capacity of the slabs were intensively investigated.It was concluded that the punching shear capacity,ductility and energy consumption decreased with the increase of RCA replacement percentage.Research findings indicated that the incorporation of steel fibres could not only improve the energy dissipation capacity and the punching shear capacity of the slab,but also effectively improve the integrity of the slab tension surface and thereby changing the trend from typical punching failure pattern to bending-punching failure pattern.On the basis of the test,the punching shear capacity formula of RAC slabs with and without steel fibres was proposed and discussed.

关键词： recycled aggregate concrete steel fibres slab punching shear recycled coarse aggregates replacement percentage

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Persistence in tillage decisions: aggregate data analysis

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International Soil and Water Conservation Research 2019年第2期7卷 109-118页

作者： Dat Q.Tran Lyubov A.Kurkalova University of Arkansas at Fayetteville AR 72701Department of Agricultural Economics and AgribusinessUSA Can Tho University Department of Hydraulic EngineeringVietnam 1601 E.Market St. GreensboroNC27411North Carolina A&T State UniversityDepartment of EconomicsUSA 1601 E.Market St. GreensboroNC27411North Carolina A&T State UniversityDepartment of Energy and Environmental SystemsUSA

The Emission Gap Report 2013 from the United Nations Environment Program showed that adopting conservation tillage such as no-till,as an alternative to conventional tillage,contributes significantly to climate change mitigation through carbon sequestration.However,substantial amounts of soil carbon are lost when farmers interrupt continuous use of conservation tillage with conventional tillage.Conservation tillage is spreading,but little is known about the behavioral persistence in tillage decisions.To address the gap in the literature,we estimate county-specific Markov models of tillage-crop choices,and use the predicted probabilities of alternative two-and three-year tillage rotations to evaluate spatial variation and temporal persistence in conservation tillage adoption for the state of lowa (U.S).We find that the county-average probabilities of continuous conservation tillage range between 0.133 and 0.295,and vary significantly among crop rotations.We also find a statistically strong positive effect of the incidence of the highly erodible land on the county-average use of continuous conservation tillage.Our results underscore the importance of dynamic modeling for understanding behavioral persistence in tillage decisions,and the interdependence between farmers' crop and tillage rotations.

关键词： aggregate data Continuous conservation tillage Markov chain model Crop rotations Highly erodible land

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