Overloaded vehicles have a significant impact on pavement fatigue life and distress. As the studies show, the phenomena intensify when the control of traffic is poor. The paper presents the results of the research including analysis of weigh in motion data from eight stations and analysis of asphalt pavement fatigue caused by mixed traffic. Distributions of vehicles axles load including the multiple axles effects are presented. Mixed axle loads were transformed into equivalent number of standard 100 kN axle loads. The regression model of load equivalency factor depending on the axle load distribution and the percentage of overloaded vehicles is presented. The analysis of the effect of overloaded vehicles on decrease of fatigue life of a pavement structure is presented. The analysis has shown that the increase of percentage of overloaded vehicles from 0% to 20% can reduce the fatigue life of asphalt pavement upto 50%.

Analysis of effect of overloaded vehicles on fatigue life of flexible pavements based on weigh in motion (WIM) data

At a certain point in the life of a flexible pavement, rehabilitation is required to improve pavement condition and to defer reconstruction. Pavement managers seek the best rehabilitation treatment on the basis of cost effectiveness. Using 1994–2002 data from a wet-freeze mid-Western state in the United States, this paper analyzes the cost effectiveness of four flexible pavement rehabilitation treatments: functional hot-mix asphalt (HMA) overlay, structural HMA overlay, resurfacing (partial 3R standards), and mill full-depth and asphaltic concrete overlay. The performance indicator used is the international roughness index and treatment effectiveness is measured in terms of performance jump (short-term), and service life and increase in pavement performance (long-term). The treatment cost is the equivalent uniform annual cost per lane-km incurred by the agency and user; and cost effectiveness is the ratio of effectiveness to cost. The study estimated treatment effectiveness under various combinations of traffic loading and climatic condition, and initial pavement condition. The results suggest that in the short-term, HMA structural overlay is the most effective treatment. For the long-term, the results are equivocal: HMA structural overlay is most effective from the perspective of average performance over the treatment life; resurfacing (partial 3R standards) is the most effective from the perspective of treatment service life. With regard to cost effectiveness, however, the results were consistent: for all three measures of treatment effectiveness, mill full-depth and asphaltic concrete overlay unequivocally appears to be the most cost effective treatment. Finally, the paper recommends that cost effectiveness analysis should be accompanied by a candid deliberation of project constraints, the local environment, and agency practices.

Evaluating the Cost Effectiveness of Flexible Rehabilitation Treatments Using Different Performance Criteria

Waste engine oil influences on chemical and rheological properties of different asphalt binders

Cracking in the asphaltic layer of pavements has been shown to be a major source of distress in roadways. Previous studies in asphaltic mixture cracking typically have not considered the material heterogeneity. The sequel of a study in which the binder and the aggregates were treated as distinct materials is presented. Besides consideration of the viscoelastic behavior of the bulk asphalt binder, a micromechanical viscoelastic cohesive zone model introducing ductility at the crack tip has been considered. The simulations performed are verified and calibrated from simple and conventional laboratory tests. The study investigates crack evolution under monotonic loading, even though the method outlined can be further developed for the investigation of asphalt mixture fatigue.

Model for predicting damage evolution in heterogeneous viscoelastic asphaltic mixtures

Complex modulus and complex Poisson’s ratio from cyclic and dynamic modal testing of asphalt concrete

The objective in this study was to check the validity of the time-temperature superposition principle for hot-mix asphalt (HMA) with growing damage and viscoplastic strain in the compression state, which is essential for the permanent deformation characterization of HMA. Constant crosshead rate compression tests were conducted at temperatures between 25° and 55°, and data were analyzed to construct the stresslog reduced-time master curves for various strain levels. Research results indicate that HMA with growing damage remains thermorheologically simple in the temperature range used in this study and that the time-temperature shift factor is only a function of temperature and is independent of the strain level. Two types of tests, the repeated creep and recovery test and the cyclic sinusoidal loading test, were performed in this study to validate the time-temperature superposition in loading histories commonly used in asphalt mixture testing. The results further confirm that the time-temperature superposi...

Time-Temperature Superposition for Asphalt Mixtures with Growing Damage and Permanent Deformation in Compression

A new approach for the characterization of linear viscoelastic (LVE) behavior of asphalt concrete is presented in this study. The proposed approach uses the associated function of the origi...

Characterization of Linear Viscoelastic Behavior of Asphalt Concrete Using Complex Modulus Model

Construction of triaxial dynamic modulus master curve for asphalt mixtures

The mechanistic-empirical pavement design guide (MEPDG) developed under National Cooperative Highway Research Program Project 1-37A requires the use of axle load spectra or load distribution factors (LDFs) for pavement thickness designs. The MEPDG allows for various levels of LDF inputs, varying from site-specific (level 1) to regional average (level 2) and national average (level 3). There exists a concern that the MEPDG level 2 and level 3 inputs do not take any site-specific information into consideration and thus may result in erroneous thickness design. This study proposed a new approach to determine the axle LDF and number of axles per truck (NAPT) for level 2 and level 3 inputs. The proposed approach requires that the design guide provide default LDFs and NAPTs for both normally loaded and overloaded trucks for various axle types and vehicle classes. Thus, design engineers can estimate LDFs and NAPTs for a particular project site based on the percentages of overloaded trucks of that site which are ...

Determination of axle load spectra based on percentage of overloaded trucks for mechanistic-empirical pavement design

This paper presents a triaxial storage modulus master curve model and a continuous relaxation spectrum model for characterizing the linear viscoelastic (LVE) properties of asphalt concrete subjected to confining pressure. The triaxial master curve model relates the reduced storage modulus to the reduced frequency by performing both horizontal and vertical shifting on storage modulus test results. The horizontal shifting is used to characterize the time- and temperature-dependent behavior of asphalt concrete, while the vertical shifting is to characterize the pressure-dependent behavior. The vertical shift factor has the form of a sigmoidal function and varies with the reduced frequency and confining pressure. A relaxation spectrum model as well as a long-time equilibrium modulus model has been derived from the triaxial master curve model via integral transforms of basic LVE equations and complex algebra. The model predictions agree well with the laboratory test results of three asphalt mixtures indicating the proposed models can accurately characterize the LVE behavior of asphalt concrete under confinement.

Yanqing Zhao

Papers

Time-Temperature Superposition for Asphalt Mixtures with Growing Damage and Permanent Deformation in Compression

Characterization of Linear Viscoelastic Behavior of Asphalt Concrete Using Complex Modulus Model

Construction of triaxial dynamic modulus master curve for asphalt mixtures

Determination of axle load spectra based on percentage of overloaded trucks for mechanistic-empirical pavement design

Characterization of linear viscoelastic properties of asphalt concrete subjected to confining pressure