Development and optimization of object detection technology in pavement engineering: A literature review

Due to the rapid advancement of the transportation industry and the continual increase in pavement infrastructure,it is difficult to keep up with the huge road maintenance task by relying only on the traditional manual detection method.Intelligent pavement detection technology with deep learning techniques is available for the research and industry areas by the gradual development of computer vision technology.Due to the different characteristics of pavement distress and the uncertainty of the external environment,this kind of object detection technology for distress classification and location still faces great challenges.This paper discusses the development of object detection technology and analyzes classical convolutional neural network(CNN)architecture.In addition to the one-stage and two-stage object detection frameworks,object detection without anchor frames is introduced,which is divided according to whether the anchor box is used or not.This paper also introduces attention mechanisms based on convolutional neural networks and emphasizes the performance of these mechanisms to further enhance the accuracy of object recognition.Lightweight network architecture is introduced for mobile and industrial deployment.Since stereo cameras and sensors are rapidly developed,a detailed summary of three-dimensional object detection algorithms is also provided.While reviewing the history of the development of object detection,the scope of this review is not only limited to the area of pavement crack detection but also guidance for researchers in related fields is shared.

Experimental assessments of methanol-based foaming agent in latex modified foamed binders and warm asphalt mixtures

Latex is one of the natural rubbers that is used to enhance the performance of asphalt pavement for the last few decades.The presence of latex,which is categorized as an elastomer,helps to improve pavement performance and durability.Conversely,higher viscosity of latex modified asphalt binder increases the production-temperatures of asphalt mixture,thus consuming higher energy during asphalt mixture’s production stage.In this study,the effectiveness of methanol as an energy-efficient foaming agent was assessed to reduce the viscosity and enhance the workability of the modified asphalt binder.The basic and rheological properties of the asphalt binders were determined through multiple laboratory tests including expansion ratio and half-life,rotational viscosity,softening point,torsional recovery,and dynamic shear rheometer.The properties of asphalt mixtures were assessed through the service characteristics,mechanical performance,and moisture resistance criteria.It was found that the presence of latex results in an approximately twofold higher expansion ratio and a lower half-life of the asphalt binder at about the same ratio.Through the rotational viscosity test,the application of methanol into asphalt binder decreased the viscosity and led to better workability,despite the addition of latex as an asphalt modifier.The application of methanol into asphalt binder improved the workability of mixture samples and lowered the compaction energy of the compaction process,which are the crucial criteria for a better mixing and compaction process.Methanol foamed asphalt mixtures with latex show much higher resistance to moisture damage and stiffness than control sample even though they were prepared at a lower temperature.

Rheological and MECHANICAL Performance of Asphalt Binders and Mixtures Incorporating CaCO3 and LLDPE

This study was conducted to assess the performance of modified asphalt binders and engineering properties of mixtures prepared with incorporation 3 vol%and 6 vol%of calcium carbonate(CaCO3),linear low-density polyethylene(LLDPE),and combinations of CaCO3 and LLDPE.The rheological properties of control and modified asphalt binders were evaluated using a series of testing such as rotational viscometer(RV),multiple stress creep recovery(MSCR)and bending beam rheometer(BBR)tests.Meanwhile,four-point beam fatigue test,the dynamic modulus(E*)test and tensile strength ratio(TSR)test were conducted to assess the engineering properties of asphalt mixtures.Based on the findings,the RV and MSCR test result shows that all modified asphalt binders have improved performance in comparison to the neat asphalt binders in terms of higher viscosity and improved permanent deformation resistance.A higher amount of CaCO3 and LLDPE have led modified asphalt binders to better recovery percentage,except the asphalt binders modified using a combination of CaCO3 and LLDPE.However,the inclusion of LLDPE into asphalt binder has lowered the thermal cracking resistance.The incorporation of CaCO3 in asphalt mixtures was found beneficial,especially in improving the ability to resist fatigue cracking of asphalt mixture.In contrast,asphalt mixtures show better moisture sensitivity through the addition of LLDPE.The addition of LLDPE has significantly enhanced the indirect tensile strength values and tensile strength ratio of asphalt mixtures.

New innovations in pavement materials and engineering:A review on pavement engineering research 2021

Sustainable and resilient pavement infrastructure is critical for current economic and environmental challenges.In the past 10 years,the pavement infrastructure strongly supports the rapid development of the global social economy.New theories,new methods,new technologies and new materials related to pavement engineering are emerging.Deterioration of pavement infrastructure is a typical multi-physics problem.Because of actual coupled behaviors of traffic and environmental conditions,predictions of pavement service life become more and more complicated and require a deep knowledge of pavement material analysis.In order to summarize the current and determine the future research of pavement engineering,Journal of Traffic and Transportation Engineering(English Edition)has launched a review paper on the topic of"New innovations in pavement materials and engineering:A review on pavement engineering research 2021".Based on the joint-effort of 43 scholars from 24 well-known universities in highway engineering,this review paper systematically analyzes the research status and future development direction of 5 major fields of pavement engineering in the world.The content includes asphalt binder performance and modeling,mixture performance and modeling of pavement materials,multi-scale mechanics,green and sustainable pavement,and intelligent pavement.Overall,this review paper is able to provide references and insights for researchers and engineers in the field of pavement engineering.

Three-dimensional modeling and simulation of asphalt concrete mixtures based on X-ray CT microstructure images

X-ray CT （computed tomography） was used to scan asphalt mixture specimen to ob- tain high resolution continuous cross-section images and the meso-structure. According to the theory of three-dimensional （3D） reconstruction, the 3D reconstruction algorithm was investi- gated in this paper. The key to the reconstruction technique is the acquisition of the voxel posi- tions and the relationship between the pixel element and node. Three-dimensional numerical model of asphalt mixture specimen was created by a self-developed program. A splitting test was conducted to predict the stress distributions of the asphalt mixture and verify the rationality of the 3D model.

Review on evolution and evaluation of asphalt pavement structures and materials

The purpose of this study was to summarize the wide-range literatures on asphalt pavements, explore the evolution of road pavements, analyze typical asphalt pavement structures, highlight current trends in research and industry, and to recommend future areas of research and development. In this research, road pavement evolution was explored from the earliest roads to the modern pavements. A new method was recommended to categorize asphalt pavement materials into the three large families which may be further sub-divided according to their mechanical parameters. A unified asphalt pavement classification(UAPC) method was proposed and the worldwide asphalt pavements could be divided into six types through the new method. Based o n the UAPC method, 1087 asphalt pavement structures were classified and analyzed to explore the asphalt thickness variation. In order to evaluate asphalt pavement performance, the Chinese design specification was employed for analyzing lives of 29 high-volume pavements and 28 low-volume pavements. Through this research, it was found that:(1) in the past 100 years, asphalt pavement materials and structures had been becoming more and more strong;(2) asphalt layer thicknesses were various from 5 to 60 cm and the overall pavement thicknesses were various from 28 to 160 cm;(3) the long-life pavements in the other countries may become"shorter-life" pavements according to the prediction based on the Chinese specification.

Research and applications of artificial neural network in pavement engineering:A state-of-the-art review

Given the great advancements in soft computing and data science,artificial neural network(ANN)has been explored and applied to handle complicated problems in the field of pavement engineering.This study conducted a state-of-the-art review for surveying the recent progress of ANN application at different stages of pavement engineering,including pavement design,construction,inspection and monitoring,and maintenance.This study focused on the papers published over the last three decades,especially the studies conducted since 2013.Through literature retrieval,a total of 683 papers in this field were identified,among which 143 papers were selected for an in-depth review.The ANN architectures used in these studies mainly included multi-layer perceptron neural network(MLPNN),convolutional neural network(CNN)and recurrent neural network(RNN)for processing one-dimensional data,two-dimensional data and time-series data.CNN-based pavement health inspection and monitoring attracted the largest research interest due to its potential to replace human labor.While ANN has been proved to be an effective tool for pavement material design,cost analysis,defect detection and maintenance planning,it is facing huge challenges in terms of data collection,parameter optimization,model transferability and low-cost data annotation.More attention should be paid to bring multidisciplinary techniques into pavement engineering to tackle existing challenges and widen future opportunities.

Effect of anisotropic characteristics on the mechanical behavior of asphalt concrete overlay

Asphalt concrete (AC)overlays placed over old asphalt pavement have become an alternative to repairing and reinforcing pavements.The strength contributed by the AC overlay is strongly influenced by the anisotropic properties of the pavement material.This study was conducted to analyze the influence of anisotropy,modulus gradient properties,and the condition of the AC overlay and old pavement contact plane on the mechanical behaviors of AC overlays,as well as to quantify the influence of the degree of anisotropy on the mechanical behaviors of AC overlay by a sensitivity analysis (SA).The mechanical behaviors of the AC overlay were numerically obtained using the three- dimensional finite element method with the aid of ABAQUS,a commercial program.Variations in the AC overlay's modulus as a function of temperature as well as the contact state between the AC overlay and AC layer were considered. The SA is based on standardized regression coefficients method.Comparing the mechanical behavior in terms of surface deflection,stress,and strain of the anisotropy model against those corresponding to the isotropic model under static loads show that the anisotropic properties had greater effects on the mechanical behavior of the AC overlay.In addition,the maximum shear stress in the AC overlay was the most significant output parameter affected by the degree of anisotropy. Therefore,future research concerning the reinforcement and repair of pavements should consider the anisotropic properties of the pavement materials.

A review on the best practices in concrete pavement design and materials in wet-freeze climates similar to Michigan

The research presented in this paper aims to identify best practices of design and materials for concrete pavements in wet-freeze climates similar to the Michigan State. For the purposes of this paper, a best practice is a procedure that has been shown by field-validated research or experience to produce improved results and that is established or proposed as a standard suitable for widespread implementation. The local wet-freeze climate makes the requirements for Michigan's pavement system different from many other regions. Wetfreeze climates can result in various concrete pavement distress mechanisms such as thermally-induced cracking, freeze-thaw deterioration, accelerated cracking due to loss of support, frost heave, and material degradation. Therefore, appropriate procedures for design and material selection need to be selected to withstand high precipitation and freezing winter temperatures. Failure to take into account the climatic conditions may lead to inadequate or reduced pavement performance. However, utilizing appropriate techniques and materials could potentially improve the quality and increase the service life of the concrete pavement. Three design methods and five materials have been identified, and examples of their successful performance in wet-freeze climates are provided. In addition, the reasons that give them the superior performance in wet-freeze climates are discussed in detail.

Review of recycling waste plastics in asphalt paving materials

An ever-growing demand for depleted natural resources is one of the significant challenges facing the global asphalt pavement industry in building and maintaining global asphalt pavements.Because plastics are ubiquitous in the global economy,they are the latest in a series of high-profile materials to attract attention.Their low material recovery rates and the environmental impact of current disposal methods pose a threat to plastic recycling.Recycling plastic wastes in asphalt pavement is a possible approach to reducing environmental pressure and the demand for depleted natural resources.Many studies have proposed recycling plastic waste in asphalt pavement using dry-and wet-processed technologies.This review aims to comprehensively evaluate the feasibility of various recycled plastics in asphalt pavement concerning the properties of compatibility,storage stability,microstructure,thermo-rheology,and mechanical performance and to identify hallenges and recommendations for the future.This review discusses recent developments and the feasibility of using plastic wastes as modifiers or additives to asphalt binders or asphalt mixtures in dry and wet processes,focusing on different materials from waste streams,how to produce such modified materials,and the characteristics of plastic waste modified asphalt,thus contributing to the sustainable management of resources and production of useful paving materials.

Comparative study of ethanol foamed asphalt binders and mixtures prepared via manual injection and laboratory foaming device

The consistency of the ethanol foamed binders and mixtures prepared using asphalt binders foamed by the manual injection technique and laboratory foaming device were evaluated and compared in this study. The asphalt binders foamed using both methods was prepared at 120℃, 130℃ and 140℃. The performance of ethanol-foamed binders was evaluated in terms of rotational viscosity, expansion ratio, and low temperature cracking.Meanwhile, the performance of foamed WMA mixtures was tested using semi-circular bending(SCB), disk-shaped compact tension(DCT), and tensile strength ratio(TSR) tests. In order to conduct the TSR test, the samples were conditioned using the Moisture Induced Stress Tester(MIST) to simulate the pore pressure and scouring effects due to a tire passing over wet pavement. The foamed WMA mixtures were produced using pre-heated aggregates at 80℃ and 100℃ and foamed asphalt binders produced at 130℃. The nano-hydrated lime was used as the filler and anti-stripping agent. Overall, the properties of ethanol-foamed binders and WMA mixtures produced via both methods are significantly comparable, except the resistance to moisture damage test result. However, the findings indicate that the ethanol-foamed WMA mixtures prepared using both techniques are having good resistance to moisture damage, based on the TSR values more than 0.8. The foamed WMA mixtures also exhibited a better resistance to cracking, as indicated by a higher tensile strength compared to the control HMA. Additionally, the WMA specimen prepared at 100℃ was less susceptible to rutting than the samples produced at 80℃.

Temperature dependency of VOCs release characteristics of asphalt materials under varying test conditions

Asphalt pavement is increasingly used in paving and roofing.However,the release of volatile organic compounds(VOCs)from asphalt harm both the environment and humans.Various methods were applied to characterize the VOCs for better understanding and inhibiting.However,asphalt VOCs have huge heating temperature dependency,which makes the asphalt VOCs’characterization complicated.In this research,three kinds of heating conditions,thermal gravimetric(TG)analyzer,pyrolysis(PY)analyzer,and thermal desorber(TD),were compared to determine the temperature dependency of VOC release characteristics.Gas chromatography and mass spectrometer(GC-MS)were then coupled for VOC detection.Results indicated that the TG heating condition can surely simulate the volatilization of VOCs from some asphalt that is not in contact with air(no oxygen)during the actual construction process,while PY and TD represent the substances released by the asphalt due to the boiling point at a certain temperature and under the actual construction process,respectively.The components detected by TG heating condition are both large and small molecules,while PY and TD heating condition will detect large molecules or small molecules,respectively.The VOC composition results under various heating conditions reflect the chemical reaction law of asphalt molecules in the heating process.When heating asphalt binders to a higher temperature,macromolecular substances will gradually crack and oxidize into small molecular substances,sulfides and nitrides.With the increase of temperature,the change trend of VOC components under different conditions is different.

Sensitivity analysis of longitudinal cracking on asphalt pavement using MEPDG in permafrost region

Longitudinal cracking is one of the most important distresses of asphalt pavement in permafrost regions. The sensitivity analysis of design parameters for asphalt pavement can be used to study the influence of every parameter on longitudinal cracking, which can help optimizing the design of the pavement structure. In this study, 20 test sections of Qinghai-Tibet Highway were selected to conduct the sensitivity analysis of longi- tudinal cracking on material parameter based on Mechanistic-Empirical Pavement Design Guide （MEPDG） and single factorial sensitivity analysis method. Some computer aided engineering （CAE） simulation techniques, such as the Latin hypercube sampling （LHS） technique and the multiple regression analysis are used as auxiliary means. Finally, the sensitivity spectrum of material parameter on longitudinal cracking was established. The result shows the multiple regression analysis can be used to determine the remarkable influence factor more efficiently and to process the qualitative analysis when applying the MEPDG software in sensitivity analysis of longitudinal cracking in permafrost regions. The effect weights of the three parameters on longitudinal cracking in descending order are air void, effective binder content and PG grade. The influence of air void on top layer is bigger than that on middle layer and bottom layer. The influence of effective asphalt content on top layer is bigger than that on middle layer and bottom layer, and the influence of bottom layer is slightly bigger than middle layer. The accumulated value of longitudinal cracking on middle layer and bottom layer in the design life would begin to increase when the design temperature of PG grade increased.

Ethanol based foamed asphalt as potential alternative for low emission asphalt technology

Foamed asphalt typically relies on water as a foaming agent because water becomes gaseous at elevated temperatures, generating numerous tiny bubbles in the asphalt and causing spontaneous foaming. In this study, ethanol was used as a potential alternative to water as a foaming agent. Ethanol is expected to be a physical blowing agent in the same manner as water, except it requires less energy to foam due to its 78 ℃ boiling point. This study compares the performance of water and ethanol as foaming agents through the measurements of rotational viscosity, the reduction in temperature during foaming, and volatile loss. The ethanol-foamed asphalt binders were prepared at 80 ~C and 100 ~C, while the water-foamed asphalt binders were prepared at 100 ~C and 120 ~＇C. Additionally, the rolling thin film oven （RTFO） was used to generate short-term aging of the foamed asphalt binders. A rotational viscometer was used to determine the viscosity of the asphalt binders at 80 ~C, 100 ~C, 120 ~C, 140 ~C, and 160 ~C. Overall, ethanol can function in the same manner as water but requires less energy to foam. It is proven based on the smaller drop in temperature of the asphalt binder foamed using ethanol compared with that prepared with water. This is due to the lower latent heat capacity of ethanol, which requires less energy to vaporize compared with water. Through the rotational viscometer test, ethanol performs better in lowering the viscosity of asphalt binders, which is essential in allowing produc- tion processes at low temperatures, as well as a better workability and aggregate coating. Ethanol can be expelled from the foamed asphalt binders at a higher rate due to its lower boiling point and latent heat.

Preface for the special issue on "Advanced Transportation Infrastructure and Materials"

The International Association of Chinese Infrastructure Pro- fessionals （IACIP） and Chang＇an University jointly hosted the first International Conference on Transportation Infrastruc- ture and Materials （ICTIM） in Xi＇an, China on July 16-18, 2016. This conference covered a variety of research topics on transportation infrastructure and materials, including pave- ment mechanics, geomechanics, highway materials, ground improvement, recycling materials, maintenance and rehabil- itation, intelligent construction, infrastructure management, intelligent transportation system, and risk and reliability. Over 200 participants from 11 countries participated in this conference, which included 13 presentation sessions, 2 workshops, and 1 forum.

A hybrid strategy in selecting diverse combinations of innovative sustainable materials for asphalt pavements

This project integrates recent innovations of recycled materials used in designing and building sustainable pavements. An increasing environmental awareness and the demand for improving economic and construction efficiencies, through measures such as con- struction warrantees and goals to reduce air pollution under the Kyoto Protocol, have increased the efforts to implement sustainable materials in roadways. The objective of this research is to develop a systematic approach toward selecting optimum combinations of sustainable materials for the construction of asphalt pavements. The selected materials, warm mix asphalt （WMA）, recycled asphalt shingles {RAS）I and reclaimed asphalt pave- ment {RAP） were incorporated in this study. The results of this research are intended to serve as guidelines in the selection of the mixed sustainable materials for asphalt pave- ments. The approach developed from this project draws upon previous research efforts integrating graphical modeling with optimizing the amount of sustainable materials based on the performance. With regard to moisture susceptibility and rutting potential test re- suits, as well as the MIM analysis based on a 95% confidence interval, the rutting perfor- mance and moisture susceptibility of asphalt mixtures are not significantly different regardless of the percentages of RAS, RAP, or WMA. The optimum mixture choices could be made by the plant emission rankings with consideration of the optimal WMA types, per- centages of RAS/RAP, and WMA production temperatures. The WMA mixtures prepared with 75% RAP and Advera WMA have produced the lowest CO2 emissions among the investigated mixture types.