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Real-time and effective early warning of highway engineering construction sites is the key to ensuring the safety of highway engineering construction. At present, highway engineering construction safety early warning is limited by the experience of relevant personnel at the site and the dynamic changes of the project site environment. Therefore, the creation of a more active, smarter, and more effective real-time early warning model for construction safety is a strong complement to current research and has important theoretical and practical implications. The Internet of Things is the third wave of the information industry after computers, the Internet, and mobile communication networks. It is of great significance to promote the development of science and technology, economic growth, and social progress. Aiming at the shortcomings of the inadequate safety management methods for highway engineering construction in China, the inefficient efficiency of safety production supervision and management, and the emphasis on single and sporty supervision methods, a real-time early warning model for highway engineering construction safety based on the Internet of Things technology was constructed. By quantifying, scoring, and statistics of the safety situation during the construction process, the model achieves the goals of real-time monitoring, early warning, and handling hidden safety hazards. It overcomes problems such as untimely and unscientific safety issues in the past and effectively improves China's highway engineering construction. The experimental comparison between the real-time early warning model and the traditional early warning model in this paper shows that the accuracy of the early warning model proposed in this paper is improved by nearly 5%, and the false alarm rate is reduced by nearly 4%. [ABSTRACT FROM AUTHOR]

Under the development strategy of traffic power, Chinese highway engineering has been in the critical stage, and controlling investment has become a top priority. The budgetary estimate is the main basis for the Chinese government to verify the highway project investment, which is estimated mainly based on the quota and price information issued by government but still lacks systematic cost indices to measure its rationality. The highway engineering cost of different regions in China varies greatly, and the accumulated cost data are not insufficient. This paper chooses the gray relation analysis-least absolute shrinkage and selection operator (GRA-LASSO) hybrid method, which has significant advantages in dealing with high-dimensional small sample data and multiple correlation variables, to establish the highway engineering budgetary estimate prediction model so as to examine the rationality of estimated investment at the initial stage of construction. Using budgetary estimate data on 121 highway projects that have been approved by the Chinese government and various macroeconomic data, the key cost drivers are identified through gray relation analysis (GRA) quantitatively, and 10 high-correlation indexes are selected as input variables. Then, the relationship among engineering characteristic variables, economic factors, and highway engineering budget are established by least absolute shrinkage and selection operator (LASSO) regression. The empirical test results show that eight indexes have significant impact on the highway cost, including earthwork quantities, route length, number of lanes, bridge-tunnel ratio, protection works quantities, highway construction investment, producer price index (PPI) and purchasing manager's index (PMI) of construction industry. Compared with ordinary least-squares (OLS) regression and LASSO method alone, the GRA-LASSO combined method has better performance in error evaluation index and stronger model accuracy and generalization ability. The study result can be mainly used for government to rapidly audit, forecast, forewarn, monitor, and manage the highway engineering cost, and also help investors and designers to pay close attention to the influence of design parameters and external environment on cost. Moreover, it provides a reference method or model for establishing a highway engineering cost index. [ABSTRACT FROM AUTHOR]

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Referring to CATIA's 'assemblies + parts' modeling method, CATIA-based BIM (Building Information Modeling) technology has been proposed for highway tunnel design in this paper. A tunnel BIM is created by CATIA, which is based on a real case in China, focusing on the following 3 aspects: (1) Creating tunnel bolts by UDF + Loop cyclic arrangement method; (2) Using Sketch Tracer module to create tunnel portal; (3) Parameter is used to create and call the Catalog database. Then, bolt collision inspection and U-shaped groove concrete statistics are conducted with the help of the tunnel BIM created. Finally, the finite element analysis of tunnel construction process is carried out through the CATIA-Midas interface. The results demonstrate that the CATIAbased BIM technology can well adapt to the characteristics of tunnel and have well potential applications in tunnel design. [ABSTRACT FROM AUTHOR]

Cement stabilized macadam semi-rigid base materials are widely used in road construction in China. However, a traditional static molding method and heavy compaction method cannot guide the design and engineering application of cement stabilized macadam mixture because it often appears that the compaction degree exceeds 100% in the practical engineering. In view of this, this paper carried out the research of an indoor vibration compaction method of cement stabilized macadam mixture, and compared the mechanical properties and void distribution characteristics of two kinds of compositions of mixtures under the vibration compaction method as well as static pressure molding and heavy compaction method and on-site sample after 7 days curing period, which was combined with the physical engineering project of Yu-Song Expressway in Jilin Province, China. The research results show that the maximum dry density of mixture under vibration compaction is larger and the best moisture content is smaller, which has a heavy incomparable advantage on the simulation of on-site compaction. And the compressive strength and splitting strength indexes of vibration compacted specimens are close to those of an on-site sample, which are all larger than static pressure specimen. Moreover, the void distribution characteristics of vibration compacted specimens is much closer to those of the on-site sample and more universal, while static pressure specimens lack in uniformity. In addition, different results caused by the two gradation are compared. All of the above research results can verify that the vibration compaction method has more reliability and accuracy to simulate the actual properties of base material. This study provides a reference for the application of vibration compaction method in road engineering design. [ABSTRACT FROM AUTHOR]

Highway construction is time consuming and complicated. Various environmental issues can be encountered during this process. Therefore, it is necessary to assess the impact of ecologic environment in highway construction. However, the traditional assessment approaches paid more attention to the environmental factors rather than the ecological problems, and the weights of evaluation indexes were assigned with relatively average values, which cannot comprehensively and accurately to assess the impact of ecological environment in highway construction. In order to solve these problems, this paper established a new model to combine improved group AHP and FCE. A total of six main factors and 22 sub-factors from three aspects of social, ecological, and natural environment were identified. The model and index system were applied to the ecological environment impact assessment of the highway from the city of Hanzhong to Lueyang County section in Shaanxi Province, and compared with traditional fuzzy AHP approach to verify the feasibility of this model. The results showed that only the ranking of social and ecological factor changed when comparing with the traditional approach. The weight of social factor determined by the improved approach was 0.2835, while that of the traditional approach was only 0.2365, and the weight difference was 0.047. This improved approach highlighted the importance of social factor and overcame the equal weight distribution of traditional approach, which made the overall weight ratio distribution more reasonable and objective. The comprehensive assessment result was 0.3482, which was in line with the "general impact" level. This was consistent with the actual situation of highway construction. The improved group AHP-FCE model could be used successfully for assessing the impact of the ecological environment in highway construction, and it had good applicability and popularization value in ecological environment assessment. [ABSTRACT FROM AUTHOR]

National park roads and parkways is an important part of national parks in the United States. The road is integrated with national parks, which is the characteristics and brand image of national parks. National park roads and parkways is not only an important means of transportation in national parks, but also a tourist attraction and destination. For tourists, driving on the national park roads and parkways means visiting the national parks. The development of national park roads and parkways embodies the integration of road engineering and aesthetics, philosophy, recreation, ecology and other disciplines, promotes the transformation of road from a single traffic function to a complex function of recreation, landscape, culture and protection, highlights the gorgeous landscape and imaginative engineering alignment, and also shows how to provide diversified recreational opportunities in protecting priceless natural and cultural resources to achieve a balance between environmental protection and public tourists. This paper makes a thorough analysis of the development process of American national park roads and parkways in the past hundred years from the aspects of concepts, development background, construction idea, development measures, management system, financial support and construction practice, and summarizes the development experience and enlightenment. The conclusion is to grasp the law of national park roads and parkways development in essence. From this point of view, the paper puts forward some suggestions for the development of China's national park roads and parkways. These studies are of great theoretical value and practical significance to the flourishing development of China's national parks, national park roads and parkways, tourist scenic byways and tourist highways. [ABSTRACT FROM AUTHOR]

Due to the complex geologic conditions in mountainous areas of China, the highways often encounter different risks induced by geological hazards during highway slope construction. In this paper, a new assessment system for highway construction risk is developed based on 11 parameters being classified into five categories. In addition, index importance ranking is proposed for a weighting coefficient distribution in the evaluation index system for the 11 parameters. This ranking substantially reduces subjectivity during the rating process. Feedback on this system has been received from many successful applications in 13 provinces of China. Therefore, the new system of slope construction risk uncertainty assessment based on index importance ranking has attracted wide attention in China. [ABSTRACT FROM AUTHOR]

The successful adoption of building information modelling (BIM) technology has led to an ever-increasing need for improving management practices in both construction and operation stages of highway project engineering. The most significant aspect of applying BIM technology is establishing the rationality and concise engineering breakdown structure (EBS) coding. However, China has no uniform EBS coding standard for highways, which limits BIM technology development in different construction projects and at different stages of the same construction project. The purpose of this study is to propose an EBS standard that embodies a coding system for highways and at the same time meets the requirements of BIM management, project management (PM), and operation management (OM) in life cycle management process. This paper presents an EBS standard based on three classifications: (1) project-level construction, (2) project-level operation, and (3) network-level operation. A case study is given to illustrate the proposed EBS standard's coding system. The new EBS system will have better adaptability in both the design and construction stages. The proposed EBS coding system has been applied in many projects and is undergoing both improvement and standardization in China. The presented EBS coding standard provides successful implementation references for the future adoption and use of BIM on PM and OM in highway projects. [ABSTRACT FROM AUTHOR]

• History of DEM and the development of DEM in China are described. • Generation of aggregates based on DEM is divided into modeling and filling. • Application of DEM in material property and mixture performance is reviewed. • Future development directions of aggregate simulation based on DEM are proposed. As one of the primary materials in asphalt mixtures, aggregates' complex morphologies and size directly affect the service performances of pavement, such as the structure stability and force transmission path. Discrete element method (DEM) can be effectively used to analyze the influence of aggregate morphology on mixture performances. In order to explore the generation method of aggregate for DEM and the application scope of DEM, the development of DEM and aggregate generation method is summarized in this paper. The process of aggregate generation is reviewed in two steps: shell construction and the model filling. User-defined and external import methods are reviewed in shell construction. Internal filling method, equal size particle filling and other filling methods are reviewed in model filling section. Various examples and principles for each method are separately summarized in the paper. Lastly, the section of test and application is used to verify the virtual experiments with different aggregates can obtain more material motion phenomena and provide more research data. This paper provides a theoretical and technical benchmark for future numerical simulation in road engineering. [ABSTRACT FROM AUTHOR]

This paper proposes a vortex-induced vibration (VIV) reliability analysis method based on the maximum entropy (MaxEnt) principle in which constraints are specified in terms of fractional moments involving uncertain wind characteristics, structural properties, and bluff-body aerodynamics. The multiplicative dimensional reduction method (M-DRM) is used to calculate the fractional moments. A new threshold is obtained based on the stopping sight distance in the highway engineering technique standard, which is less strict than the China–Japan standard and the British code and thus better-suited to VIV reliability evaluation. A long-span cable-stayed bridge model is used to illustrate the accuracy and efficiency of the proposed method in comparison to Monte Carlo simulation (MCS) on three performance functions of VIV reliability. The results indicate that VIV maximum amplitude and wind speed failure probability are not sensitive to the selected performance function, but the effect of the wind attack angle on probability is significant. The M-DRM provides a workable alternative approach to analyzing the highly complex VIV reliability of long-span bridges. [ABSTRACT FROM AUTHOR]

Li, Y., 2019. Evaluation of highway construction efficiency—a case study in coastal provinces, China.In: Li, L.; Wan, X.; and Huang, X. (eds.), Recent Developments in Practices and Research on Coastal Regions: Transportation, Environment and Economy. Journal of Coastal Research Journal of Coastal Research, Special Issue No. 98, pp. 271–276. Coconut Creek (Florida), ISSN 0749-0208. This paper quantitatively studies the performance evaluation of coastal highway construction projects within the project cycle. By constructing the performance evaluation of the coastal highway construction research analysis framework and then combining it with the characteristics of the principal component analysis and data envelopment analysis (DEA), general evaluation of coastal highway construction is put forward, along with analysis of efficiency evaluation models and finally principal component analysis of coastal highway construction and evaluation of the overall perspective of DEA evaluation of the efficiency of coastal highway construction. [ABSTRACT FROM AUTHOR]

Faced with complex air pollution and traffic congestion, the road area ratio has gradually gained great importance in society and government. It is the ratio introduced from the field of road design and road engineering, but to study the efficiency of city planning and transportation recently. However, few studies have been conducted to study the relationship between urban congestion and pollution in the view of improving road area ratio. This paper investigated the effect of increasing the relative capacity of urban roads, i.e., road area ratio, on urban air pollution using panel data from cities in China from 2006 to 2018. In addition, the road area ratio can be further decomposed to explore the inner logic of pollution from congestion. Thus, we also explored whether the insufficient network density or width caused the pollution from congestion. We found that an increasing urban road area ratio significantly reduced air pollution, regardless of whether or not the impact of surrounding cities is included. Moreover, only an increased road density can increase traffic efficiency and reduce congestion emissions, which should be the priority of future traffic construction. The effect of increasing road width is not significant. • The increase in the urban road area ratio decreases air pollution. • There exists the "neighbor effect" of pollution in urban cities. • Decomposing the road area ratio factor to road width and road network density. • Only the increased road network density reduces traffic emissions. [ABSTRACT FROM AUTHOR]

The high-modulus asphalt mixture produced by hard asphalt has played a good role in reducing asphalt pavement rutting and improving pavement durability. It was widely used in the construction of various levels of road engineering in Europe. However, low-grade hard asphalt was rarely used in road engineering in China, and the use of hard asphalt for the design and construction of high modulus asphalt mixtures lacks sufficient engineering experience. Considering the above issues, comparative research on the performance of Chinese and French low-grade hard asphalt and mixture was carried out. In this paper, the performance of French 15# hard asphalt commonly used for EME (Enrobés à Module Elevé Class) high modulus asphalt mixture and China 15# hard asphalt was analyzed comparatively, where six typical high modulus asphalt mixtures corresponding to two low-grade hard asphalts were designed referring to the design requirements of French high modulus asphalt mixtures. The road performance of a high-modulus asphalt mixture was evaluated to verify the feasibility of its application in engineering. The research results show that the performance indicators of both Chinese and French asphalts meet the requirements of binder materials used in high modulus asphalt mixtures, and the performance of their corresponding mixtures of the two asphalts also meet the specifications of high modulus asphalt mixtures. However, the two asphalts and the performance of their corresponding mixture are slightly different. The high modulus asphalt mixture of Chinese low-grade hard bitumen can be used well in road engineering applications in China. It can strongly promote the wide application of high modulus asphalt mixture in China. [ABSTRACT FROM AUTHOR]

Understanding the complex network response to nodes failure is important to protect them and guarantee their functioning. Most existing studies considered binary networks where the intensity (weight) of the links is not accounted for. However, in real world networks the intensity of the links widely differ so that a realistic description of complex networks is only possible if the heterogeneity present in edge weights is taken into account. Further, the vast majority of the existing studies investigates the efficacy of the attack strategies when all the nodes are removed. Despite it is important to study the network behavior in such a circumstance, real-world networks are more likely to experience local failures involving a small amount of nodes with a decrease in the system functioning not causing an overall collapse. This is the case of crossroad closing in complex road networks. For this reason it is interesting to investigate the networks response focusing to small node removals. In this paper we analyze the response of the real-world road networks of Beijing, the capital of China, to the removal of 1 and 2 nodes and accounting the weighted structure of the network. We use both classic binary node properties and network functioning measurement, introduced a weighted rank for node importance (node strength or page rank), and used a measurement for network functioning that accounts for the weight of the links (weighted efficiency). We find that the weighted node attack strategy Str (i.e. strength attack), which removes nodes according to their strength, is the most efficient to blemish the system when evaluating the damage with a weighted efficiency. Differently, betweenness attack strategy Bet , which removes nodes according to their centrality is the most efficient when using the binary efficiency to compute the network damage. These results indicate that adopting weighted or binary efficiency to measure networks functioning changed the efficacy of the attack strategies to damage the system. Last, we found a non-negligible fraction of random removals to be more efficient than the attack strategies; given that the main goal of the attack strategies is to individuate important nodes in the system, i.e. nodes which removal triggers highest damage, our results would indicate how in order to find the most important nodes may be more efficient to simulate an higher number of random nodes removal. [ABSTRACT FROM AUTHOR]

The freeway system of China is the longest in the world and planned to expand in the following years. However, the safety conditions of freeways are drawing increasing concerns both from the authorities and the public in the country. The safety design and management for freeways are urgently needed considering the current safety situation and great demands of new freeways. The study presented in this paper thoroughly investigated factors affecting safety using detailed data of crashes, traffic characteristics and freeway geometry. A random effects negative binomial (RENB) model was applied to account for spatial variations within groups together with a negative binomial (NB) model. The results indicated a better goodness of fit of RENB model than the NB model. In addition, a good number of factors significantly contributed to crash, such as truck proportion, presence of climbing lane, median barrier offset, curvature and longitudinal grade, were identified. This study was expected to provide a better understanding of how traffic condition and freeway design affect safety and should be useful to freeway engineers to design safe freeways, or develop effective safety countermeasures. [ABSTRACT FROM AUTHOR]

In the French high-modulus asphalt mixture design system, the complex modulus of the mixture under the conditions of 15 °C and 10 Hz is taken as the design index. However, in China, the dynamic modulus under the conditions of 15 °C, 10 Hz, 20 °C, 10 Hz and 45 °C, 10 Hz was taken as the stiffness modulus index of high-modulus asphalt mixture. The difference in modulus values between the two systems caused the pavement structure layer to be thicker and the construction cost to be higher in China. In order to find out the appropriate modulus value of high-modulus asphalt mixture suitable for China's modulus parameter conditions to better carry out the reasonable design and evaluation of high-modulus asphalt mixture in China, the modulus of four types of high-modulus asphalt mixtures under the two systems through the two-point bending complex modulus test of the CRT-2PT trapezoidal beam and the SPT uniaxial compression dynamic modulus test were analyzed in this paper. Under the premise of meeting the stiffness modulus index of the French high-modulus asphalt mixture, the relationship conversion models between the dynamic modulus and complex modulus of high-modulus asphalt mixture under different temperatures were established. According to the conversion models, the design evaluation value range of dynamic modulus suitable for China's condition was recommended. It is recommended that the dynamic modulus of China's high-modulus asphalt mixture at 15 °C and 10 Hz is not less than 16,000 MPa, the dynamic modulus at 20 °C and 10 Hz is not less than 14,000 MPa, and the dynamic modulus at 45 °C and 10 Hz is not less than 2500 MPa. Five kinds of high-modulus asphalt mixtures used in actual road engineering were tested to verify the reliability of the recommended dynamic modulus values based on the modulus conversion model, and the results are consistent with the recommended value range of the model. [ABSTRACT FROM AUTHOR]

This paper analyzes the spatial–temporal evolution of the attractiveness of a country’s gateway for its international trade, using Shanghai as an example. The attractiveness is regressed on the transportation facilities and geographical conditions. Seaport development is found to have a major positive impact, followed by inland waterway, highway, and airport development. These positive impacts decrease with the need for highway haulage and with the distance from Shanghai—showing an inverse U-shape distribution. Rail appears to have a U-shape distribution, implying a low application of multimodal transportation. A geographical pattern for the impacts of different transportation modes is delineated. [ABSTRACT FROM AUTHOR]

The design parameters are one of the important factors to ensure the quality of asphalt pavement design. In "Highway Asphalt Pavement Design Specification" (JTGD50-2017), the stander of China, used the asphalt mixture anti-pressure resilience modulus at a single temperature of 20 °C as the design metrics. However, asphalt mixture, as a sticky-bullet plastic material, shows different mechanical properties at different temperatures. China is a vast territory, and there are great differences between the high and low temperature value (m and n) of each region. Therefore, it is unreasonable to design asphalt pavement only with the asphalt mixture anti-pressure resilience modulus value at 20 °C. Studies show that the design parameters using PG technology can improve the high temperature anti-rutting and low temperature cracking performance of asphalt pavement. [ABSTRACT FROM AUTHOR]

With the rapid economic growth in China, the road transportation system was becoming one of the largest and most rapidly growing oil consumers in China. This paper focused on the current status and development trend of energy efficiency and CO 2 emission intensity of commercial trucks. According to the statistical data of commercial trucks from China's Ministry of Transport, there were 10% ∼ 30% differences about the energy efficiency and CO 2 emission intensity among different brands of trucks under the same mass section in the industry standard (JT719-2008). There have appeared a group of vehicle with low emission and high energy efficiency. Energy efficiency standards and energy efficiency label system have been proven to promote energy-saving technology progress. In order to promote the development of energy efficiency and CO 2 emission intensity of commercial trucks, the ‘Top Runner’ method was proposed to classify the energy efficiency and CO 2 emission intensity of commercial trucks by coincidence rate, which would lead the road transportation enterprises to high energy efficiency trucks. [ABSTRACT FROM AUTHOR]

On the basis of summarizing and analyzing the relevant researches in China and foreign countries, this paper carries out the study on comprehensive evaluation index system of low carbon road transport which mainly adopts the Fuzzy Evaluation method with Analytic Hierarchy Process and Delphi. The factors of low carbon road transport are divided into three categories, including road infrastructure, road traffic, road management and related policies and regulations, in which the factors that have an important impact on low carbon road transport development are chosen and analyzed. And then the chosen factors turn into the evaluation index, through the judgment matrix, fuzzy weight vector of each index is calculated and examined by the consistency test. Finally, index coefficients of each layer are obtained. In the case study part, we found out that the low carbon traffic structure development of Shanghai road network is 0.5478, which is between “good” and “general”. [ABSTRACT FROM AUTHOR]

When railway emergency lead to traffic interruption for some sections, it is indispensable for railway administration to take some urgent processing measures for transporting detained passengers and trains. This paper focuses on the method of generating train paths in traffic interruption conditions and proposed the idea that signal system compatibility is a considerable factor in the procedure of searching paths. On the basis of this idea, it was designed that the algorithm of generating train path in terms of adequate capacity strategy. The core of the algorithm is recursive dijkstra algorithm. Finally, we confirmed the practicability of algorithm through an example. The result showed that the proposed algorithm for generating train feasible paths provides references to the organization of railway traffic organization in traffic interruption conditions. [ABSTRACT FROM AUTHOR]

The expansion of road networks in emerging economies such as China causes significant greenhouse gas (GHG) emissions. This development is conflicting with China's commitment to achieve carbon neutrality. Thus, there is a need to better understand life cycle emissions of road infrastructure and opportunities to mitigate these emissions. Existing impact studies of roads in developing countries do not address recycled materials, improved pavement maintenance, or pavement-vehicle interaction and electric vehicle (EV) adoption. Combining firsthand information from Chinese road construction engineers with publicly available data, this paper estimates a comprehensive account of GHG emissions of the road pavement network to be constructed in the next ten years in the Shandong province in Northern China. Further, we estimate the potential of GHG emission reductions achievable under three scenario sets: maintenance optimization, alternative pavement material replacement, and EV adoption. Results show that the life cycle GHG emissions of highways and Class 1–4 roads to be constructed in the next 10 years amount to 147 Mt CO2-eq. Considering the use phase in our model reveals that it is the dominant stage in terms of emissions, largely due to pavement-vehicle interaction. Vehicle electrification can only moderately mitigate these emissions. Other stages, such as materials production and road maintenance and rehabilitation, contribute substantially to GHG emissions as well, highlighting the importance of optimizing the management of these stages. Surprisingly, longer, not shorter maintenance intervals, yield significant emission reductions. Another counter-intuitive finding is that thicker and more material-intensive pavement surfaces cause lower emissions overall. Taken together, optimal maintenance and rehabilitation schedules, alternative material use, and vehicle electrification provide GHG reduction potentials of 11%, 4%–16% and 2%–6%, respectively. • Road construction implies significant amounts of GHG emissions. • China's road expansion plans are at odds with its target of GHG neutrality. • We assess GHG emissions of Shandong's roads to be constructed through 2030. • We combine life cycle assessment based on primary data with a new optimization model. • Individual mitigation measures can reduce life cycle GHG emissions by up to 16%. [ABSTRACT FROM AUTHOR]

In order to evaluate the energy consumption and emission reduction effect of warm mixed asphalt (WMA) comprehensively and precisely, a novel evaluating method of the effect of WMA on emission and energy consumption of asphalt pavement construction was established and applied on the road construction project in northeast region of China. Considering the production of asphalt mixture and construction process of road engineering, a series of evaluating indices were selected and divided to the Level I and II indices respectively for establishment of evaluating system. Then, the level ranking intervals of Level I and II indices were confirmed based on the Hierarchical cluster method and Bayesian method. Finally, the single index evaluation (SIE) and multi-objective comprehensive evaluation (MOCE) methods were combined to evaluate the reducing effect of WMA on the emission and energy consumption during the highway construction process of project in northeast region of China. The results indicated that i. target WMA could achieve excellent reduction effect on COx and the reduction rate was above 60% and also promote the reducing effect on NOx and SO2 emitted during the production process of asphalt mixture. ii. The improving effect of WMA on emission was mainly reflected in the production stage of asphalt mixture rather than construction stage. iii. The application of WMA could help saving energy consumption obviously in transportation and onsite construction of asphalt mixture. This evaluating index system and method could provide reference for the reduction effect evaluation of WMA in road construction, which could help promoting the wide application of WMA in further road construction project. [ABSTRACT FROM AUTHOR]

The resonant compaction method using a crisscross-shaped probe was implemented in highway engineering projects for eliminating liquefaction in the east coastal region of China. To evaluate the compaction effectiveness in the treatment of liquefiable sand deposits with clay lenses, seismic piezocone tests (SCPTUs) and standard penetration tests (SPTs) were performed, as well as excess pore water pressure measurements. The results showed that the cone stress, sleeve friction, shear wave velocity and SPT blows increased due to vibratory compaction, and the soil liquefiable potential was eliminated. The execution of projects was highly efficient due to the simple compaction procedure and the quick dissipation of excess pore water pressure. However, the existence of a clay lens reduced the compaction effectiveness, particularly the development of SPT blows. Nevertheless, the resonant compaction method was still applicable for the treatment of soils with low to mild liquefaction levels and provided an alternative soil liquefaction countermeasure with remarkable benefits in efficiency and convenience. [ABSTRACT FROM AUTHOR]

Freeze–thaw weathering is critical to road engineering in seasonally frozen regions. To solve the adverse effects of inorganic stabilization materials on the environment, the lignin of the original polymer compound is used to improve the durability of silty clay. Lignin content, curing duration, and freeze-thawing were determined to have a significant influence on the geotechnical properties and microstructure of lignin-treated silty clay. An increase in lignin content resulted not only in an increase in the optimum moisture content, pH, and water absorption of the soils, but also a decrease in the maximum dry density, plasticity index, specific gravity, thermal conductivity, and swelling capacity. In contrast, an increase in lignin content led to an initial increase followed by a decrease in the liquid limit, plastic limit, and California bearing ratio of the soils. After freeze-thawing, the thermal conductivity and California bearing ratio of lignin-treated silty clay decreased, whereas the swelling capacity and water absorption increased. The optimum lignin content for silty clay in the Jilin Province of China is approximately 4%. The soil particles are bonded with the cementitious material. No new mineral composition, chemical elements, or functional groups are formed after the treatment. The bearing capacity and frost resistance of lignin-treated silty clay are affected by the cementitious materials, coated grains, and filled pores. [ABSTRACT FROM AUTHOR]

Taking advantage of the state-of-the-art graphene preparation technologies in China and abroad, this work studied the preparation processes of graphene for road applications based on the preliminary high-speed vibration ball milling method. This work combined numerical modeling and microscopic experiments. The preparation parameters were optimized through a multifactor and multilevel test scheme. The materials, influencing factors, and parameters in the preparation process were systematically studied. A graphene preparation method was proposed that considered vibration frequency, static filling rate, material-to-ball volume ratio, and the void percentages of media. Flake graphite, aluminum powder, and 304 stainless-steel grit were used as the preparation materials. The preparation parameters and process model were established based on the uniform design method. The preparation parameters were proposed, calculated, and optimized. Microscopic analysis showed that the proposed preparation method can improve the quality of graphene. This study provides a new source of raw materials for the application of graphene in road engineering. [ABSTRACT FROM AUTHOR]

A good estimation of additional stress of a bridge approach foundation overlying embankment is of great importance in order to accurately calculate the differential settlements of foundation due to the axisymmetric distribution of the additional stress. Current design method commonly adopted in road and railway engineering in China is derived from the classical elastic theory and simply considers the embankment load by its self-weight (γh) without taking into account the influence of the width-to-height ratio. This may lead to an overestimation of additional stress and consequently an uneconomical overdesign. This study attempts to mitigate the gap by developing a new analytical solution. Based on the Boussinesq's elastic theory, the proposed solution considers a constrained boundary condition associated with bridge abutment and incorporates a new concept of ground reaction, which takes into account the embankment load including the influence of the embankment width-to-height ratio. The proposed solution was finally validated by numerical analysis and shows a better performance in terms of additional stress estimation over the traditional calculation method. Overall, the proposed method proved to be a better alternative tool for the design of bridge approach embankment. [ABSTRACT FROM AUTHOR]

Predicting vehicle carbon emissions on vertical curve sections can provide guidance for low-carbon vertical profile designs. Given that the influence of vertical curve design indicators on the fuel consumption and CO2 emissions of vehicles are underexplored, this study filled this research gap by establishing a theoretical carbon emission model of vehicles on vertical curve sections. The carbon emission model was established based on Xu's vehicle energy conversion model, the conversion model of energy, fuel consumption, and CO2 emissions. The accuracy of the theoretical carbon emission model and the CO2 emission rules on vertical curve sections were verified by field test results. Field tests were carried out on flat sections, longitudinal slope sections, and various types of vertical curve sections, with five common types of vehicles maintaining cruising speed. The carbon emission rate effects on the vertical curve are closely related to the gradient and irrelevant of the radius. On the vertical profile composed with downhill/asymmetric/symmetrical vertical curve with a gradient greater than the balance gradient, the carbon emission rate is determined by the gradient and radius. The influence of the gradient on carbon emissions of vehicle on these vertical profiles was more significant than the radius. The radius is irrelevant to the carbon emission rate on the other forms of vertical profile. These results may benefit highway designers and engineers by providing guidelines regarding the environmental effects of highway vertical curve indexes. [ABSTRACT FROM AUTHOR]

Rutting has been one of the primary concerns for highway engineers in China. Granulated polymer anti-rutting additive may be an effective way to solve this problem. However, it is difficult to find previous research on the application of granulated polymer as an anti-rutting additive in different types of asphalt mixtures. This research aims to investigate the influences of the anti-rutting additive contents on road performances based on different types of asphalt mixtures, and also explores potential reasons for road performance improvement. Three types of asphalt mixtures: dense-graded asphalt concrete (DG-AC), dense-graded Superpave (DG-Superpave)，semi-open-graded asphalt macadam (SOG-AM), were included. Road performances, including high-temperature performance, low-temperature performance and moisture susceptibility, were studied at three anti-rutting additive percentages: 0.2, 0.3 and 0.4% weight of the asphalt mixture. The mixtures without the anti-rutting additive were regarded as control groups. In order to better analyse the road performance improvements, the properties of modified asphalt with 0.4% anti-rutting additive were studied, as well as the anti-rutting additive physical form in the asphalt mixture. It was found that the anti-rutting additive improved mixture's high-temperature performance significantly while its effects on low-temperature performance were not so. It reduced low-temperature tensile strain within 12.9% range. Moisture susceptibility was improved greatly after adding 0.2% anti-rutting additive as compared to the corresponding control groups. By increasing the additive contents to 0.3 and 0.4%, the moisture susceptibility had no significant difference compared with that of the 0.2% additive content group. Road performance improvements may relate to the combined action of reinforcement and gap filling by the elongated anti-rutting additive, as well as asphalt modification within short time. When the additive content is no more than 0.3%, the materials costs of the additive-modified asphalt mixtures are less than that of SBS-modified asphalt mixtures. [ABSTRACT FROM AUTHOR]

Evaluation indices were proposed and rated based on statistical analysis of collapse by an improved backward cloud algorithm considering internal and trigger factors. The evaluation index weight was calculated by a G1 method. A hazard evaluation of a highway collapse in China was established on the basis of a spatial analysis function of ArcGIS 10.2 and a factor superposition method. A hazard zoning of highway collapse in China was also performed based on the hazard degree. Results show that a comprehensive hazard index of highway collapse hazard in China based on the evaluation index above ranges from 1.0 to 9.0; and the distribution law of the collapse along a highway coincides with the actual distribution of highway collapse hazard. The most dangerous zones are the mountainous area of Southeast Taiwan, the mountainous area of Southeast Fujian–Zhejiang, south of Hainan, Sichuan–Yunnan mountainous area, Tianshan Mountains and Kunlun Mountains. The results can provide a reference for highway collapse prevention and mitigation work. Abbreviations: AHP: Analytic Hierarchy Process; GIS: Geographic Information System [ABSTRACT FROM AUTHOR]

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To uniform the evaluation indicators of Styrene-Butadiene-Styrene (SBS) modified asphalt, the SK70# and SK90# matrix asphalt were modified by different SBS modifier dosage in this study. The test methods in China and Superpave were used to test the performance of each SBS-modified asphalt respectively, from which the appropriate evaluation index of SBS-modified asphalt was determined. The results showed that the addition of SBS modifier improved the high temperature performance and lowered the temperature sensitivity of asphalt binder, while it increased the viscosity of asphalt binder in high temperatures. Due to the variability that appeared in the results of the penetration test by the swelling of SBS-modified asphalt, the penetration test was not recommended to evaluate the performances of SBS-modified asphalt. The softening point of SBS-modified asphalt with the modifier dosages of 4.5%, 5%, 5.5% and 6% increased 5.7%, 12.8%, 22.5% and 26.4% respectively compared to the matrix asphalt for SK70# matrix asphalt, and increased 21.2%, 26.3%, 33.6% and 46.6% respectively compared to the matrix asphalt for SK90# matrix asphalt. The effect of SBS-modifier on the softening point of SK90# matrix asphalt is significantly better than that of SK70# matrix asphalt. The improvement effect of SBS modifier on low temperature performance of matrix asphalt decreased with a decrease in test temperature. When studying the influence of the SBS modifier on the low temperature performance of asphalt binder, it was recommended to use the bending beam rheometer (BBR) test to evaluate the low temperature performance of SBS-modified asphalt. [ABSTRACT FROM AUTHOR]

It has been previously documented that under the condition of crossing an uncontrolled intersection, the decision-making process of drivers is rather complex and highly interactive: they need to decide about the timing, direction, and strategy to complete the required maneuver to avoid potential conflicts. Given the significant impact of this behavior on intersection safety and capacity, we model the merging behavior of a straight-moving vehicle facing a turning vehicle at an uncontrolled intersection in China. We expect that this model can predict the probability that a straight-moving driver has a preemptive status (i.e., arrive at the merging point before the turning vehicle). The factors which determine the drivers' decision behavior are analyzed, and then we propose a logistic regression model using a dataset collected from an uncontrolled intersection in Kunming, China. Our model reveals that the speed difference, the distance between the two vehicles, and the distance of the turning vehicle to the merging point are the major determinants of a straight-moving driver's decision. In addition, the prediction results from our model are compared with real-world observations, and better validate the decision behavior model in China. [ABSTRACT FROM AUTHOR]

Highways provide key social and economic functions but generate a wide range of environmental consequences that are poorly quantified and understood. Here, we developed a before–during–after control-impact remote sensing (BDACI-RS) approach to quantify the spatial and temporal changes of environmental impacts during and after the construction of the Wujing Highway in China using three buffer zones (0–100 m, 100–500 m, and 500–1000 m). Results showed that land cover composition experienced large changes in the 0–100 m and 100–500 m buffers while that in the 500–1000 m buffer was relatively stable. Vegetation and moisture conditions, indicated by the normalized difference vegetation index (NDVI) and the normalized difference moisture index (NDMI), respectively, demonstrated obvious degradation–recovery trends in the 0–100 m and 100–500 m buffers, while land surface temperature (LST) experienced a progressive increase. The maximal relative changes as annual means of NDVI, NDMI, and LST were about −40%, −60%, and 12%, respectively, in the 0–100m buffer. Although the mean values of NDVI, NDMI, and LST in the 500–1000 m buffer remained relatively stable during the study period, their spatial variabilities increased significantly after highway construction. An integrated environment quality index (EQI) showed that the environmental impact of the highway manifested the most in its close proximity and faded away with distance. Our results showed that the effect distance of the highway was at least 1000 m, demonstrated from the spatial changes of the indicators (both mean and spatial variability). The approach proposed in this study can be readily applied to other regions to quantify the spatial and temporal changes of disturbances of highway systems and subsequent recovery. [ABSTRACT FROM AUTHOR]