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Journal of Road Engineering 2024年第2期4卷 224-233页

作者： Ikenna D.Uwanuakwa Ilham Yahya Amir Lyce Ndolo Umba Department of Civil Engineering Near East UniversityMersin 10Turkey Faculty of Sciences University of LubumbashiLubumbashiThe Democratic Republic of Congo

This study introduces and evaluates a novel artificial hummingbird algorithm-optimised boosted tree(AHAboosted)model for predicting the dynamic modulus(E*)of hot mix asphalt *** a substantial dataset from NCHRP Report-547,the model was trained and rigorously *** metrics,specifically RMSE,MAE,and R2,were employed to assess the model's predictive accuracy,robustness,and *** benchmarked against well-established models like support vector machines(SVM)and gaussian process regression(GPR),the AHA-boosted model demonstrated enhanced *** achieved R2 values of 0.997 in training and 0.974 in testing,using the traditional Witczak NCHRP 1-40D model *** features such as test temperature,frequency,and asphalt content led to a 1.23%increase in the test R2,signifying an improvement in the model's *** study also explored feature importance and sensitivity through SHAP and permutation importance plots,highlighting binder complex modulus|G*|as a key *** the AHA-boosted model shows promise,a slight decrease in R2 from training to testing indicates a need for further ***,this study confirms the AHA-boosted model as a highly accurate and robust tool for predicting the dynamic modulus of hot mix asphalt concrete,making it a valuable asset for pavement engineering.

关键词： Asphalt dynamic modulus Prediction Artificial hummingbird algorithm Boosted tree

Experimental study on the dynamic modulus of compacted loess under bidirectional dynamic load

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Earthquake Research Advances 2022年第3期2卷 58-66页

作者： Liguo Yang Shengjun Shao Qilong Sun Ping Wang Institute of Geotechnical Engineering Xi0an University of TechnologyXi0an710048China Department of Civil and Traffic Engineering Yellow River Conservancy Technical InstituteKaifeng475003China Shaanxi Key Laboratory of Loess Mechanics and Engineering Xi0an University of TechnologyXi0an710048China

The dynamic characteristics of compacted loess are of great significance to the seismic construction of the Loess Plateau area in Northwest China,where earthquakes frequently *** study the change in the dynamic modulus of the foundation soil under the combined action of vertical and horizontal earthquakes,a hollow cy-lindrical torsion shear instrument capable of vibrating in four directions was used to perform two-way coupling of compression and torsion of Xi'an compacted loess under different dry density and deviator stress *** results show that increasing the dry density can improve the initial dynamic compression modulus and initial dynamic shear modulus of compacted *** an increase in the deviator stress ratio,the initial dynamic compression modulus increases,to a certain extent,but the initial dynamic shear modulus decreases *** dynamic modulus gradually decreases with the development of dynamic strain and tends to be stable,and the dynamic modulus that reaches the same strain increases with an increasing dry *** the initial stage of dynamic loading,the attenuation of the dynamic shear modulus with the strain development is faster than that of the dynamic compression *** with previous research results,it is determined that the dynamic modulus of loess under bidirectional dynamic loading is lower and the attenuation rate is faster than that under single-direction dynamic *** deviator stress ratio has a more obvious effect on the dynamic compression *** increase in the deviator stress ratio can increase the dynamic compression modulus,to a certain ***,the deviator stress ratio has almost no effect on the dynamic shear modulus,and can therefore be ignored.

关键词： Bidirectional dynamic load Compacted loess dynamic modulus Dry density Deviator stress ratio Ground treatment

Influence of repeated freeze-thaw on dynamic modulus and damping ratio properties of silty sand

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Research in Cold and Arid Regions 2013年第5期5卷 572-576页

作者： TianLiang Wang Chao Ma Han Yan JianKun Liu School of Civil Engineering Shijiazhuang Tiedao University Key Laboratory of Roads and Railway Engineering Safety Control of Ministry of Education Shijiazhuang Tiedao University School of Civil Engineering Beijing Jiaotong University Northwest Corporation China Railway Construction Engineering Group

Under repeated freezing and thawing in deep seasonal frozen regions, the stability and strength of the soil are imposed in the form of large uneven settlement, instability and strength reduction, which affect the normal operation of railway lines. This study is to obtain the influencing rules of freeze-thaw on the dynamic properties （dynamic strain, confining pressure and compactness） of silty sand. Based on an amount of inner tests, the dynamic modulus and damping ratio properties of silty soil subjected to repeated freeze-thaw cycles were deeply researched and analyzed. The results are as follows： At the same dynamic strain, the relationship of dynamic stress and freeze-thaw cycles presents negative cor- relation, and the relationship of dynamic stress, confining pressure and compactness present positive correlation. The dynamic modulus double decreases while the damping ratio double increases with incremental increase in dynamic strain. The dynamic modulus sharply decreases while the damping ratio increases with incremental increase in freeze-thaw cycles, and then the changes level off after six freeze-thaw cycles. The dynamic modulus increases while the damping ratio decreases as the confining pressure and compactness increase at the same strain level.

关键词： freeze-thaw cycles silty sand dynamic modulus damping ratio

Development of a dynamic modulus Prediction Model for Hot Mixture Asphalt and Study of the Impact of Aggregate Type and Its Electrochemical Properties

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Open Journal of Civil Engineering 2020年第3期10卷 213-225页

作者： Mouhamed Lamine Chérif Aidara Makhaly Ba Alan Carter UFR Sciences de l’Ingénieur Université de Thiès Thiès Sénégal Ecole de Technologie Supérieure (ETS) Director of Pavement Bituminous Materials Laboratory (LCMB) Montréal Canada

The most famous model known in prediction of dynamic modulus for asphalt concretes is the Witczak and Hirsh models. These models didn’t use the mineralogical and chemical properties of aggregates. Witczak models used the passing or refusal percentage to sieve diameters and Hirsh model used the volumetric analysis. All models developed until now considered that the aggregates were geotechnical conforming to standards. In this study the first mineralogical and chemical properties were considered through the percentage of silica in the rock source of aggregates and the electric aggregate particles charge zeta. Dynamic modulus values used for regression process are determined from complex modulus test on nine asphalt concretes mix designed with aggregate types (basalt of Diack, quartzite of Bakel and Limestone of Bandia). Between Twelve initial inputs, the statistical regression by exclusion process keeps only seven parameters as input for the model. The mineralogical model showed good accuracy with R2 equal to 0.09. The student test on the model parameters showed that all the parameters included in the model were meaningful with good p inferior to 0.05. The Fisher test on the model showed the same result. The analysis of the sensitivity of the mineralogical model to zeta potential showed that the dynamic modulus increases with the positive zeta-potentials and decrease

关键词： dynamic modulus Mineralogical Basalt of Diack Quartzite of Bakel Limestone of Bandia Zeta Potential Silica

Evaluation of dynamic modulus of HMA Sigmoidal Prediction Models and Optimization by Approach of U.S. Mesh Sieve by AFNOR and LC Mesh Sieve

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Open Journal of Civil Engineering 2020年第3期10卷 195-212页

Pavement design tools are not universal. Indeed, in the sizing of pavements in the USA, the prediction models used in the calculation of the dynamic modulus of HMA are not adapted to the characterization of the mineral skeleton of the HMA mix designed with the French method. This article aims to assess the predictive models of the dynamic modulus used in the mechanistic-empirical design for their use in the design of bituminous pavements, and to develop new predictive models taking into account the sieve series LC and AFNOR standards. A total of six types of mixtures were subjected to the determination of complex modulus testing by direct tensile-compression on cylindrical specimens (26-700 LC) over a temperature range (5) and frequency (5) data. Dynamic modulus prediction models |E*| are studied Witczak model 1999 and model Witczak 2006. These models do not take into account the AFNOR or LC mesh sieve, an approach was made in relation to the US mesh sieve to replace ρ200 (0.075 mm), ρ4 (4.76 mm), ρ38 (9.5 mm) and ρ34 (19 mm) respectively by the AFNOR mesh P0.08 (0.08 mm), <

关键词： dynamic modulus Mechanistic-Empirical Design US Sieve Mesh HMA AFNOR LC

Influence of Hydrodynamic Pore Pressure Damage on the Performance of Hot-Mixed Renewable Asphalt Mixture

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Journal of Renewable Materials 2023年第5期11卷 2453-2467页

作者： Guodong Zeng Chao Li Yang Fang Hongming Huang Hao Li Yishen Xu Foshan Transportation Science and Technology Co. Ltd.Foshan528315China Key Laboratory of Road Structure and Material of Ministry of Transport(Changsha) Changsha University of Science&TechnologyChangsha410114China School of Highway Engineering Chang’an UniversityXi’an710064China

For evaluating the water stability of hot-mixed renewable asphalt mixture(HRM),the traditional methods are all tested under still water *** for damage in still water conditions,the hydrodynamic pore pressure generated by the tire driving on the surface water has a great ***,the RAP contents of the HRMs were designed at 0%,30%,45%and 60%with AC-25 ***,the self-designed evaluation methods of water stability and dynamic modulus were ***,the mechanism of the influence of hydrodynamic pore pressure damage on HRMs was *** results show that the water stability of HRM containing 30%RAP is equivalent to that of 45%RAP,and the water stability of HRM containing 60%RAP decreases *** Contabro test after MIST treatment can be used as an evaluation method for hydrodynamic pore pressure damage on ***-speed,heavy-load traffic and larger RAP content have greater damage to the mixture after hydrodynamic pore pressure *** performance differences between the aged bitumen and pure bitumen,as well as the aged minerals and new minerals,are continuing to be enlarged in hydrodynamic pore pressure conditions,finally affecting the water stability and dynamic modulus of the HRMs.

关键词： Hot-mixed renewable asphalt mixture water stability dynamic modulus hydrodynamic pore pressure

Investigation of flow behavior of crude oils with emphasis to upper Assam Basin,India

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Petroleum Research 2022年第2期7卷 263-268页

作者： Bondita Robidas Subrata Borgohain Gogoi Department of Petroleum Technology Dibrugarh UniversityDibrugarhAssamIndia

This paper attempts to investigate the viscoelastic nature of eight Crude Oil(CO)samples from the Upper Assam Basin,*** was studied using dynamic Mechanical Analysis(DMA)where shear stress was applied to the CO samples and the resulting displacement(shear strain)was *** transportation through pipelines face serious problems due to their high pour(PP)point and *** this work,dynamic modulus(G*)was calculated using which the storage and the loss modulus were determined to study the elastic and viscous nature of the samples at 30C as the average Pour Point(PP)of the CO samples was near 30***,especially during the extreme winter season in Assam,when the ambient temperature falls drastically,the lighter components come out from the liquid and precipitates in the inner wall of the pipeline which affects the flow through the ***,a better understanding of the flow behavior of CO is very important as this will help to identify whether flow improving methods are required or ***,in this work viscoelastic properties of the CO samples were investigated from where yield point was *** points or the Yield Point(YP)of the samples were determined to understand the flow characteristics before and after the crossover *** the CO samples were observed to be viscous after the yield point except for two CO *** stress and yield strain of the samples were calculated from the YP,which exhibited non-Newtonian behavior with maximum yield stress up to *** reaching the YP,the CO samples showed the dominance of viscous nature over elastic nature except for two *** tangent or tan q was also calculated to validate the viscoelasticity of the *** study was done to investigate the flow behavior of CO samples of the Upper Assam Basin for pipeline transportation.

关键词： Viscoelasticity Shear strain Yield stress dynamic modulus Loss tangent

Predicting the dynamic Behavior of Asphalt Concrete Using Three-dimensional Discrete Element Method

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Journal of Wuhan University of Technology(Materials Science) 2012年第2期27卷 382-388页

作者：陈俊 PAN Tongyan CHEN Jingya HUANG Xiaoming LU Yang College of Civil and Transportation Engineering Hohai UniversityNanjing 210098China Department of Civil Engineering CatholicUniversity of AmericaWashington DC 20064USA School of Transportation Southeast UniversityNanjing 210096China Department of Civil and Environmental Engineering Virginia Polytechnic Institute and State UniversityVA 24061USA

A user-defined three-dimensional （3D） discrete element model was presented to predict the dynamic modulus and phase angle of asphalt concrete （AC）. The 3D discrete element method （DEM） model of AC was constructed employing a user-defined computer program developed using the ＂Fish＂ language in PFC3D. Important microstructural features of AC were modeled, including aggregate gradation, air voids and mastic. The irregular shape of aggregate particle was modeled using a clump of spheres. The developed model was validated through comparing with experimental measurements and then used to simulate the cyclic uniaxial compression test, based on which the dynamic modulus and phase angle were calculated from the output stress- strain relationship. The effects of air void content, aggregate stiffness and volumetric fraction on AC modulus were further investigated. The experimental results show that the 3D DEM model is able to accurately predict both dynamic modulus and phase angle of AC across a range of temperature and loading frequencies. The user- defined 3D model also demonstrated significant improvement over the general existing two-dimensional models.

关键词： asphalt concrete dynamic modulus micromechanics discrete element method three-dimensional model uniaxial compression test

Effects of Fibers on the dynamic Properties of Asphalt Mixtures

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Journal of Wuhan University of Technology(Materials Science) 2007年第4期22卷 733-736页

作者：吴少鹏 Key Laboratory of Silicate Materials Science and Engineering of Ministry of Education(Wuhan University of Technology)

The dynamic characteristics of fiber-modified asphalt mixture were investigated. Cellulose fiber, polyester fiber and mineral fiber were used as additives for asphalt mixture, and the dosage was 0.3%, 0.3%, 0.4%, respectively. dynamic modulus test using SuperPave simple performance tester （SPT） was conducted to study the dynamic modulus （E＇） and phase angle （δ） for the control asphalt mixture and fiber-modified ones at various temperatures and frequencies. Experimental results show that all fiber-modified asphalt mixtures have higher dynamic modulus compared with control mixture. The dynamic modulus master curves of each type of asphalt mixtures are determined based on nonlinear least square regression in accordance with the time- temperature superposition theory at a control temperature （21.1℃）. The fatigue parameter E^＊×sinδ and rutting parameter E^＊/sinδ of asphalt mixture are adopted to study the fatigue and rutting-resistance properties, and experimental results indicate that such properties can be improved by fiber additives.

关键词： fiber asphalt mixture dynamic modulus phase angle master curve

The Characteristics of Asphalt Mixture in the System of Full Thickness Cold In-place Recycling

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Journal of Wuhan University of Technology(Materials Science) 2017年第6期32卷 1402-1407页

作者：王海峰 MA Baoguo College of Civil Engineering Huaqiao University Xiamen 361021 China School of Materials Science and Engineering Wuhan University of Technology Wuhan 430072 China

A new research method was proposed（A/S method） to study the components and properties of reclained asphalt mixture（RAP）. The RAP was divided into two main parts, one was marked with A that included all the reclaimed old asphalt materials（including some parts of particle materials covered by asphalt）, the other was marked with S which mainly included works soil in the road structure. The actual working conditions were simulated by this kind of new method, and the adaption between the RAP properties, A/S, and the content of cementitious materials were studied. The research indicated that the real working condition could be simulated effectively by means of A/S method. It was also showed that high content of cement could improve the overall performance of RAP significantly, but it would have a negative effect on the properties of RAP if the types and sizes of aggregate particles in RAP mixture were too single. The optimum water content and maximum dry density could not be regarded as the primary basis to evaluate the overall performance of RAP, when S=0 in the experiments, although the maximum density of samples was bigger than that with A/S=1/1, the samples were not strong enough and they were easy to collapse, which indicated that component design of RAP played a great role in improving the overall properties of RAP and the comprehensive tests should be considered to evaluate the stability of RAP. Low frequency load in high temperature environment had the negative effect on the overall stability of RAP, and factors such as the loading state of the materials, the hydration degree of cementitious materials, and the aggregate gradation in the mixture were the determining factors for improving the overall performance of RAP.

关键词： full thickness cold in-place recycling(FTCIR) reclaimed asphalt pavement (RAP) splittingstrength compressive strength dynamic modulus