Guide for Pavement Friction

Pavement surface friction is one of the most important contributing factors in highway safety. It is a function of a pavement's micro- and macro texture. Therefore, tracking changes in pavement surface friction and texture depth during a pavement's service life is critical for maintaining driving safety and comfort. As part of FHWA's Long-Term Pavement Performance (LTPP) study, many state highway agencies have been collecting friction data to track these changes on designated test sections. In Connecticut, six LTPP sections were constructed in 1997 to serve as Special Pavement Study 9A sites for the characterization of Superpave® asphalt mixtures. This paper presents an analysis of pavement friction and texture data collected by the Connecticut Department of Transportation on these sections. Friction numbers were obtained with an ASTM E274 locked-wheel pavement friction tester by using smooth (ASTM E524) and ribbed (ASTM E501) tires and a GripTester fixed-slip pavement friction tester. Estimated texture depths were obtained in accordance with ASTM E1845 at each site with a Dynatest laser texture device mounted to the friction tester. In addition, mean profile depths were measured with a Circular Track Meter in accordance with ASTM E2157. The analysis of the results targeted three main objectives. First, the variability of the skid number values, measured by the locked-wheel and the braked-wheel, fixed-slip methods, was evaluated. Next, some empirical relationships between friction number and texture depth developed in previous studies were verified. Last, the friction and texture data were analyzed to correlate the measurements with surface material properties.

The paper gives the major characteristics of the prestressed highway pavements which have been built in the United States during 1971-73, together with reasons for their design features. Construction and prestressing data are cited for demonstration and research project of the Federal Highway Administration at Dulles International Airport; early-age slab movements and restraints, and performance observations of slabs over two years old. The paper describes the advantages of natural stress conditions existing in long pavement slabs, which counteract the maximum flexural traffic load tension stresses. Longitudinal prestress maintains these favorable stress conditions most effectively. Concrete and steel requirements in prestressed pavement and conventional highway pavement construction are compared, showing substantial savings of both concrete and steel in prestressed pavements, in addition to a better utilization of both materials by prestressing. Suitable criteria for design and construction of future prestressed highway and airport pavement projects are suggested.

Tire-pavement interaction is a critical analysis for conducting friction measurements and safety evaluation on highway pavements. Substantial field studies and research efforts indicate pavement friction can be predicted with tire/texture-related models (e.g. empirical or analytical models); however, developing a reliable friction prediction model for network level pavement survey still remains a challenge. In this paper Heinrich/Klüppel friction prediction model is utilized to estimate friction on Asphalt Concrete (AC) pavements. High resolution texture data are acquired from Ames high-speed profiling system, and subsequently pavement friction data are collected on the same sections with Dynatest 6875 Highway friction tester. Findings from the study indicate a good agreement between the predicted and measured Friction Numbers (FNs). It is concluded that Heinrich/Klüppel friction theory can be used as a promising surrogate for pavement safety evaluation. This study would be beneficial for complementing the existing safety evaluation methods used in highway safety program.

Assessing highway pavement condition is crucial for ensuring transportation safety and optimizing infrastructure maintenance. In Xinjiang, China, extreme climatic and traffic conditions pose significant challenges to pavement performance. This study introduces a machine-learning-based framework to predict asphalt pavement performance in Xinjiang. We integrate various factors (design, materials, environment, traffic, and maintenance) into regression models, creating a region-specific pavement performance decay model. Our data preprocessing methodology effectively addresses outliers and missing data, ensuring the model’s robustness. The findings offer insights into asphalt pavement behavior in Xinjiang and provide guidance for maintenance strategies. The proposed model enhances highway infrastructure safety and cost-effectiveness. Future research will focus on refining the model with more data and exploring complex variable interactions.

Актуальность работы. Слоистые среды ‒ одни из наиболее часто встречающихся объектов в инженерно-строительной деятельности человека. С одной стороны они представляют собой грунтово-геологические массивы, а с другой, например, взаимодействующие с ними дорожные одежды автомобильных дорог. Исследование напряженно-деформированного состояния дорожных одежд автомобильных дорог служит основой для решения многих инженерных задач, и в последние годы осуществляется, как правило, с применением геофизических методов. Выработка эффективных критериев анализа состояния дорожных одежд на основе геофизических подходов, опирающихся на анализ диссипации энергии динамического деформирования, может в значительной степени послужить повышению их долговечности и надежности в течение жизненного цикла. Цель работы. Исследование процессов диссипации энергии деформирования в слоистых средах на примере дорожных одежд автомобильных дорог и установление качественных взаимосвязей между жесткостью отдельных слоев и диссипацией энергии деформирования в них. Методы. В рамках исследования выполнялись экспериментальные исследования диссипации энергии деформирования на поверхности дорожной одежды, и отдельных ее слоев по мере строительства. В качестве опытного участка был выбран строящийся участок автомобильной дороги Iкатегории на Юге России. Для экспериментального анализа использовалась установка динамического нагружения с падающим грузом FWD PRIMAX 1500, позволяющая осуществлять регистрацию динамических петель гистерезиса как на поверхности отдельных слоев дорожной одежды, так и на поверхности автомобильной дороги. Результаты. Впервые рассчитаны количественные значения уровней диссипации энергии деформирования для дорожной одежды автомобильной дороги, и установлена их связь с жесткостными характеристиками конструктивных слоев. Установлено, что верхние тонкие слои покрытий дорожных одежд, обладающие большей вязкостью в сравнении с остальными слоями, служат «демпфером», поглощающим и рассеивающим энергию деформирования, позволяющим предохранять нижние слои от накопления деформаций и микроразрушений Relevance. Layered half-space are among the most frequently encountered objects in human engineering and construction activities. On the one hand they represent soil-geological massifs, and on the other hand, for example, roadways interacting with them. The study of stress-strain state of highway pavements serves as a basis for solving many engineering problems, and in recent years is carried out as a rule with the use of geophysical methods. The development of effective criteria for analyzing the state of road pavements on the basis of geophysical approaches, based on the analysis of dissipation of dynamic deformation energy, can significantly serve to increase their durability and reliability during the life cycle. Aim. To study the processes of deformation energy dissipation in layered half-space on the example of road pavements of highways and to establish qualitative relationships between the stiffness of individual layers and the dissipation of deformation energy in them. Methods. Experimental investigations of the dissipation of deformation energy on the surface of the road pavement and its separate layers during construction were carried out within the framework of the research. For the experimental analysis we used a dynamic loading unit with a falling load FWD PRIMAX 1500, which allows to register dynamic hysteresis loops both on the surface of separate layers of pavement and on the surface of the completed highway. Results. For the first time quantitative values of the levels of dissipation of deformation energy for the A-135 highway pavement have been calculated and their relationship with the stiffness characteristics of structural layers has been established. The assumption is made, confirmed by the results of experimental measurements, that the upper thin layers of pavements with higher viscosity compared to other layers serve as a “dampener” absorbing and dissipating the deformation energy, allowing to protect the lower layers from the accumulation of deformation and micro-destruction

An extensive literature review was conducted to synthesize past and ongoing research related to highway pavement maintenance and preservation techniques. The literature review was augmented with a web-based email survey that was distributed to all 50 U.S. states, the District of Columbia and 11 Canadian provinces, for a total of 62 recipients. The literature review and survey results provide interesting qualitative overviews of the state-of-the-practice of preventive maintenance treatments, and how these treatments are instigated, managed, and accessed by transportation department personnel throughout North America. This report focuses on studies that quantified the performance of various preventive maintenance treatments, including the effect these treatments have on pavement performance. The study indicates that ranges of reported life expectancies for treatment systems vary widely, as does reported unit costs. The lack of conclusive quantitative data is attributed to variations in the many aspects of treatment systems. Additional research is needed to quantify and enhance our understanding of the short and long-term effects that treatment systems have on highway pavement surfaces. State- or region-specific research is critically important to ensure that funds are wisely used for extending the life of a pavement section or for repairing ailing pavement surfaces.

Activities associated with the development of the revised AASHTO Guide for the Design of Pavement Structures (1986 edition) prompted the AASHTO Joint Task Force on Pavements (JTFOP) recommendation to immediately initiate research with the objective of developing mechanistic pavement analysis and design procedures suitable for use in future versions of the AASHTO guide. The mechanistic-empirical (M-E) principles and concepts stated in the AASHTO guide were included in the NCHRP 1-26 (Calibrated Mechanistic Structural Analysis Procedures for Pavements) project statement. It was not the purpose of NCHRP Project 1-26 to devote significant effort to develop new technology but to assess, evaluate, and apply available M-E technology. Thus, the proposed processes and procedures were based on the best demonstrated available technology. NCHRP Project 1-26 has been completed and the comprehensive reports are available. M-E flexible pavement design is a reality. Some state highway agencies (Kentucky and Illinois) have already established M-E design procedures for new pavements. M-E flexible pavement design procedures have also been developed by industry groups (Shell, Asphalt Institute, and Mobil). The AASHTO JTFOP continues to support and promote the development of M-E procedures for pavement thickness design and is facilitating movement toward an M-E procedure. The successful and wide-scale implementation of M-E pavement design procedures will require cooperating and interacting with various agencies and groups (state highway agencies, AASHTO—particularly the AASHTO JTFOP, FHWA—particularly the Pavement Division and Office of Engineering, and many material and paving association industry groups). It is not an easy process, but it is an achievable goal.

State highway agencies (SHAs) are required by Federal Highway Administration (FHWA) to develop Transportation Asset Management Plans (TAMP) in which the performance targets for roadway assets are determined. FHWA also developed national performance metrics to use in determining performance targets for pavements. However, for pavement assets, most SHAs employ their own performance metrics for pavement condition data reporting and performing maintenance and rehabilitation (M&R) analysis. Therefore, there is a need to incorporate national performance measures into SHAs’ pavement management system to support the development of TAMP. In this study, new pavement performance metrics were proposed to assist SHAs in conducting M&R analysis. The relationships between the new metrics and existing pavement metrics used in the State of Tennessee were investigated. Comparison between the new metrics and the State’s metrics was made with reference to network-level condition summary and performance prediction models. Results indicated that the new performance metrics appeared to be stable and less sensitive to sectioning method. Similar time-series patterns of network-level performance deterioration were found between the State’s metrics and the new metrics. It is recommended that performance models be established based on the new metrics, as the deterioration rates from the two metrics were not well correlated.

The majority of State Highway Agencies now employ statistical-based specifications for the acceptance of highway materials and pavement construction. The parameters of these statistical acceptance plans are specified based on engineering judgment and may result in a high level of risk to both the agency and contractor. To appropriately apply such specifications to the pavement construction industry, the associated production quality (i.e., materials and construction variability) must be well understood by all parties involved, and its potential effects need to be assessed. To address this, the objective of this study is to quantify the risks to the agencies and contractors (i.e., Type I and Type II errors) associated with the use of both single and multiple acceptance quality characteristics through constructing operating characteristic curves. It is also the purpose of this study to provide guidelines to properly implement the key components of an acceptance plan and its associated statistics. The methodology and findings identified in this study can be applied elsewhere to evaluate the acceptance plans and the associated risks related to highway materials and pavement construction.

Nano materials are being used in concrete technology to enhance performance grade sustainably of construction field works like rigid highway pavement. Nano materials like Nano Al2O3 are used as admixture for the cementitious materials to improve the mechanical and durability properties related to the physio-chemical reactions. The overall objective of this research is to evaluate the effects of Nano Al2O3 addition on the abrasion durability response of concrete pavement. These investigations are conducted to study different Nano Al2O3 contents (0.5, 1, 1.5, 2%) by weight of cement on the concrete strength and abrasion resistance by using the manufactured calibrated rotary cutter device for evaluation process and microstructure analysis by Scanning Electronic Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) tests. The compressive strength was tested at 28 days of curing and the results showed that the compressive strength of concrete increases up to 36% at 28 days by addition of 1% nano-alumina as a replacement of cement; Optimal content (1% by weight of cement) is found that appears better abrasion, durability abrasion performance and at the same time, achieves the main requirement of concrete highway pavement (strength and workability).

The Georgia Department of Transportation (GDOT) has adopted and been actively using Geographic Information Systems (GIS) technology to improve its 18,000-centerline-mile (28,962-km) system's highway pavement management for the past few years. An Oracle client/server and GIS-based pavement management module were developed by Georgia Tech and has been successfully implemented by GDOT since 2000. This client/server-based GIS module was designed to integrate seamlessly with the Oracle central database in which the pavement condition survey data reside. Once the pavement condition data surveyed by 60 field engineers had been uploaded on the central database, the managers were able to visualize statewide pavement conditions, including the project ratings and various distresses, such as load cracking, block cracking, rutting, etc., in real time. Managers were able and can now perform spatial analyses by aggregating features, such as working districts and congressional districts. The successful implementation of the GIS module in GDOT has greatly enhanced pavement management capability by generating data that had been previously unavailable and by obtaining pavement condition data in seconds instead of days. In this paper, examples are used to demonstrate the actual benefits of implementing the client/server-based GIS module. Also, future research about using GIS in pavement management is discussed.

Present developments in the field of pavement-management systems are primarily concerned with seeking relations between users' costs and variable pavement parameters. In this respect, the description and assessment of pavement-surface characteristics with regard to vehicle-pavement interaction and its stochastic character are of extreme importance. Only such an approach makes it possible to obtain both justified criteria and sought limit values for the models describing their development during pavement performance under traffic loads and the effect of climatic factors. The marked stochastic character is inherent not only in surface characteristics as such, but also in the response of the vehicle and measurement equipment during their travels along the pavement. Therefore, theoretical foundations are presented along with assessment methods, response-type measuring devices, and routine methods used in the measurements of surface characteristics of highway and airfield pavements based on the theory of random functions, which have been introduced in Czechoslovakia. The ascertained relations of pavement-surface characteristics are expressed most frequently by means of power spectral densities. Numerous results of in-site measurements, particularly by the mass-scale data collection in the highway network, may be processed in such a way that simple analytical functions or numerical constants may be deduced. However, the solution is always based on random-process theory and respects the vehicle-pavement interaction. This simplified approach also forms the basis of the classification of vehicle response by means of the variance of vertical acceleration and, in a derived manner, also the classification of pavement unevenness by means of a logically introduced unevenness index. The selected probabilistic approach based on vehicle dynamics also causes certain difficulties and limitations, for example, in the identification of the pavement-surface megatexture band (wavelengths from 0.5 up to 100 m) or in the solution of the influence of the respective unevenness band on skid resistance, which concerns tire-pavement interaction. In spite of these problems, the stochastic concept of the solution of the problems of pavement-surface characteristics can be considered an efficient instrument which can considerably accelerate the finding of the sought relations between the technical and economic parameters in the design of the structure and quantification of the couples in full management systems.

Rutting is one type of major distress, it exhibits a negative impact to the serviceability characteristics of the flexible pavement, to the residual life of pavement structure and to the safety and ride quality for traffic. Monitoring the accumulation of pavement distress is beneficial in obtaining the deterioration model which can be implemented in the decision of maintenance. Moreover, such model can focus on the properties of materials with sustainable behavior. Simple empirical relationship between the elastic strain and the long-term plastic behavior of pavement materials was established. The aim of this work is to study the in-service behavior of pavement material and relates the pavement layers composition to pavement age. The -expired life since construction- of Asphalt concrete pavement of Mosul-Baji highway was related to gradation variables, Asphalt and voids content and structural properties variables (Marshall properties, and Stiffness). An Asphalt Concrete deterioration model was developed by combining the data from laboratory testing on core and slab specimens obtained from the various layers of the pavement and performing a regression analysis. The model describes the structural deterioration of Asphalt Concrete pavement. It was concluded that such modeling may give a correct basis for treatment planning, project evaluation, management and funding.

Proper highway drainage is essential to ensure safe and comfortable conditions for the road users. The highway pavement and inlet geometry, especially cross slope and longitudinal slope and local depression and transition length, usually determine the highway surface drainage capacity. In this study, FLOW-3D is utilized to model the unsteady free-surface flow through curb opening inlets with different longitudinal and cross slopes. FLOW-3D, developed by the Flow Science, Inc., is a three-dimensional computational fluid dynamics software that can be utilized as “Virtual Lab” to study complex flow problems. FLOW-3D utilizes a true volume of fluid method (TruVOF) to compute free surface motion and the fractional area/volume obstacle representation (FAVOR) technique to model complex geometric regions. Flow characteristics near curb opening inlets are carefully examined. Inlet efficiency is determined from flow simulation results for the inlets with various longitudinal and cross slopes, especially for small slopes where laboratory tests were not able to be conducted. Inlet efficiencies for curb opening inlets with different transitional lengths before and after the inlet are examined using FLOW-3D simulation models. Simulation results are compared with laboratory observations with good agreement.

Small-format aerial photography (SFAP) is a low-cost solution for bridge-surface imaging and is proposed as a remote bridge-inspection technique to supplement current bridge visual inspection. Providing top-down views, photos taken from airplanes flying at 305 m (1,000 ft) allow for the visualization of subinch (i.e., large) cracks and joint openings on bridge decks or highway pavements. An onboard global positioning system can help geo-reference images collected and allow automated damage detection. However, the site lighting, surrounding tree shades, and highway surface reflectivity may affect the quality of the images. Several examples of bridge evaluation using SFAP are presented to demonstrate the capability of remote sensing as an effective tool for bridge-construction monitoring and condition assessment. A deck condition rating technique for large crack detection is proposed to quantify the condition of the existing bridge decks.