Driving Simulation Study on Speed-change Lanes of the Multi-lane Freeway Interchange

AbstractBecause of the interactions of the multi-lane freeway mainline, upstream, downstream, the diversity of environmental conditions, as well as the complexity of geometric configuration, speed-change lanes of the multi-lane freeway interchange present greatest safety and operational challenges for drivers. Most freeway crashes occur in the vicinity of interchange diverging and merging areas, especially in speed-change lanes. In this paper, the UC-win/Road5 software was used as the technical tool, and a three-dimensional driving scene was built. Multi-lane freeway field data were used for the calibration of model parameters. The geometry configuration of the speed-change lanes as well as the driving behavior characteristics such as speed, acceleration rate, glancing in the diverging and merging areas were studied in this paper. Based on the driving simulation study in the areas, results supply a valuable technical reference for speed-change lane geometry configuration, the length design of speed-change lane, the operational safety evaluation of multi-lane freeway diverging and merging areas, also the operation and management of multi-lane freeways

Driving Simulator Validity of Driving Behavior in Work Zones

Driving simulation is an efficient, safe, and data-collection-friendly method to examine driving behavior in a controlled environment. However, the validity of a driving simulator is inconsistent when the type of the driving simulator or the driving scenario is different. The purpose of this research is to verify driving simulator validity in driving behavior research in work zones. A field experiment and a corresponding simulation experiment were conducted to collect behavioral data. Indicators such as speed, car-following distance, and reaction delay time were chosen to examine the absolute and relative validity of the driving simulator. In particular, a survival analysis method was proposed in this research to examine the validity of reaction delay time. The result indicates the following: (1) most indicators are valid in driving behavior research in the work zone. For example, spot speed, car-following distance, headway, and reaction delay time show absolute validity. (2) Standard deviation of the car-following distance shows relative validity. Consistent with previous researches, some driving behaviors appear to be more aggressive in the simulation environment. Document type: Articl

Evaluating the performance of sustainable perpetual pavements using recycled asphalt pavement in China

The vast highways network in China is moving from the phase of construction to the phase of maintenance, and with the introduction of new technique of perpetual pavement in last decade, it is necessary to consider recycling as one of the promising solutions for rehabilitation of old asphalt concrete pavement and ultimately to convert them into perpetual pavements. The aim is to reuse the existing pavement materials for several reasons, mainly to preserve natural resources such as aggregates, and to satisfy economic requirements by reducing the cost of highway construction and rehabilitation. A detailed testing program has been carried out on recycled asphalt pavements materials (RAP) to evaluate their mechanical and structural characteristics to be used for the construction and rehabilitation of road pavements. Different types of RAP mixes have been stabilized by Portland cement to find the most suitable one from the point of view of design, construction, economy and environment. The analysis of life cycle costs has been carried out using system analysis and management of pavement program (SAMP5). The analysis of life cycle costs showed that the use of Portland cements with small percentages improves the structural characteristics of recycled asphalt materials to be used as stabilized base pavement layers for new or rehabilitated old road pavements and also for the construction and rehabilitation of perpetual pavements. A large amount of savings in construction and rehabilitation cost has been achieved by the use of stabilized RAP materials in addition to important contributions to the environment and preserving of natural resources

Feasibility of perpetual pavement stage construction in China: A life cycle cost analysis

The main objective of pavement design and management is to build sustainable pavement structure with minimum costs during its whole life. There are many uncertainties in the process of pavement design pertaining many of its variables, such as future traffic estimation, long time behavior of materials, future weights and types of traveling vehicles, availability of funds etc. Therefore, it is important to apply pavement stage construction technique during the process of pavement design and management to minimize the risk associated with these uncertainties. From the beginning of 2000, the research and application of perpetual asphalt pavement (PP) technology has been deployed in China. The semi rigid base for asphalt pavement has been normally considered as typical component of high class highways in the design according to the Chinese experience since 1997. The research objective is to apply pavement stage construction for the evaluation of life cycle costs of Chinese perpetual and traditional semi rigid pavements using operational pavement management system in addition to examine its suitability for design and construction of more economical and durable flexible pavements. It has been found that the stage construction of asphalt layers in PP over semi rigid pavement foundation will create more sustainable and trusted pavement structures in spite of 2–5% increase in present total cost

Evaluating life cycle costs of perpetual pavements in China using operational pavement management system

Highway transportation is considered as vital factor in China’s economic growth; many high grade highways have been constructed in China during the last decades. The research and application of perpetual asphalt pavement (PP) technology have been deployed in China since 2000. The semi-rigid pavement has been normally considered as typical pavement of high class highways in the design according to the Chinese experience. The objective of this research is to evaluate the performance of different Chinese perpetual pavements using operational pavement management system and to examine its suitability for use in the design and construction of more economical and durable pavements. It has been found that the use of thin asphalt layers over semi-rigid pavement foundation in PP structure will create more sustainable, economical, and durable PP structures in comparison with typical thick asphalt layers PP structures

Driving Simulator Validity of Driving Behavior in Work Zones

Driving simulation is an efficient, safe, and data-collection-friendly method to examine driving behavior in a controlled environment. However, the validity of a driving simulator is inconsistent when the type of the driving simulator or the driving scenario is different. The purpose of this research is to verify driving simulator validity in driving behavior research in work zones. A field experiment and a corresponding simulation experiment were conducted to collect behavioral data. Indicators such as speed, car-following distance, and reaction delay time were chosen to examine the absolute and relative validity of the driving simulator. In particular, a survival analysis method was proposed in this research to examine the validity of reaction delay time. The result indicates the following: (1) most indicators are valid in driving behavior research in the work zone. For example, spot speed, car-following distance, headway, and reaction delay time show absolute validity. (2) Standard deviation of the car-following distance shows relative validity. Consistent with previous researches, some driving behaviors appear to be more aggressive in the simulation environment

Research on the Viscosity-Temperature Properties and Thermal Stability of Stabilized Rubber Powder Modified Asphalt

A stabilized rubber powder-modified asphalt was provided for the field of rubber asphalt, and the optimal blending amount of stable rubber powder was determined from indicators, such as penetration, penetration index, ductility, softening point, and viscosity at 135 °C. The viscoelastic curve was measured, and the thermal storage stability test showed that the stabilized rubber powder-modified asphalt has significant thermal storage stability. The specific surface area, scanning electron microscope, and differential scanning calorimeters were used to analyze the dispersion state and aggregation state of the rubber powder particles in the stabilized rubber powder-modified asphalt, etc. The swelling state and reaction mechanism of the rubber powder in the stabilized rubber powder-modified asphalt have been characterized. The results show that the temperature sensitivity of the asphalt was improved after the stabilized rubber powder was added. The content of the stabilized rubber powder was determined to be 30%, which effectively reduces the viscosity at 135 °C, and the workability is improved; the impact of rubber powder-modified asphalt was less than that of ordinary rubber asphalt, but the temperature should be strictly controlled to ensure the viscosity of stable rubber powder-modified asphalt; the specific surface area comparison test shows that the stable rubber powder has better performance than ordinary rubber powder and asphalt matrix. The advantage of having a larger contact area enhances the compatibility of stabilized rubber powder with asphalt; scanning electron microscopy and differential scanning calorimeters test results show that the stable rubber powder-modified asphalt is mainly based on the compatibility mechanism, and a series of processes, such as oil absorption swelling-high temperature shear-compatible dispersion, occur

Research on the Viscosity-Temperature Properties and Thermal Stability of Stabilized Rubber Powder Modified Asphalt

A stabilized rubber powder-modified asphalt was provided for the field of rubber asphalt, and the optimal blending amount of stable rubber powder was determined from indicators, such as penetration, penetration index, ductility, softening point, and viscosity at 135 °C. The viscoelastic curve was measured, and the thermal storage stability test showed that the stabilized rubber powder-modified asphalt has significant thermal storage stability. The specific surface area, scanning electron microscope, and differential scanning calorimeters were used to analyze the dispersion state and aggregation state of the rubber powder particles in the stabilized rubber powder-modified asphalt, etc. The swelling state and reaction mechanism of the rubber powder in the stabilized rubber powder-modified asphalt have been characterized. The results show that the temperature sensitivity of the asphalt was improved after the stabilized rubber powder was added. The content of the stabilized rubber powder was determined to be 30%, which effectively reduces the viscosity at 135 °C, and the workability is improved; the impact of rubber powder-modified asphalt was less than that of ordinary rubber asphalt, but the temperature should be strictly controlled to ensure the viscosity of stable rubber powder-modified asphalt; the specific surface area comparison test shows that the stable rubber powder has better performance than ordinary rubber powder and asphalt matrix. The advantage of having a larger contact area enhances the compatibility of stabilized rubber powder with asphalt; scanning electron microscopy and differential scanning calorimeters test results show that the stable rubber powder-modified asphalt is mainly based on the compatibility mechanism, and a series of processes, such as oil absorption swelling-high temperature shear-compatible dispersion, occur

Research on Fatigue Prediction Model of Asphalt Mixture with High RAP Content

Asphalt pavement hot recycling technology can improve resource utilization efficiency, reduce energy waste and CO2 emissions, and bring huge economic and social benefits, further promoting the realization of “carbon peak and carbon neutrality”. This paper uses single logarithmic regression fitting on the fatigue failure life of recycled asphalt mixture with high RAP content to characterize the influence of RAP content (R), stress ratio (C), loading frequency (H) and test temperature (T) on the fatigue life of recycled asphalt mixture. Subsequently, the relationship between fatigue life and stress ratio of recycled asphalt mixture, under the influence of different RAP content, loading frequency and test temperature was analyzed. The results showed that the fatigue life of recycled asphalt mixture decreased with an increase in RAP content, stress ratio and test temperature, and decreased as loading frequency increased. Fatigue life and stress ratio were found to be approximately logarithmic, and based on the relationship between fatigue equation parameters a, b and R, T, H, the fatigue prediction model for recycled asphalt mixtures with independent variables R, C, H, and T was established

RETRACTED: Ma et al. Research on Fatigue Prediction Model of Asphalt Mixture with High RAP Content. <i>Sustainability</i> 2021, <i>13</i>, 7995

The journal retracts the article entitled “Research on Fatigue Prediction Model of Asphalt Mixture with High RAP Content” cited above by Ma et al. [...