Abstract
In Iraq rutting is considered as a real distress in flexible pavements as a result of high summer temperature, and increased axle loads. This distress majorly affects asphalt pavement performance, lessens the pavement useful service life and makes serious hazards for highway users. Performance of HMA mixtures against rutting using Mechanistic- Empirical approach is predicted by considering Wheel-Tracking test and employing the Superpave mix design requirements. Roller Wheel Compactor has been locally manufactured to prepare slab specimens. In view of study laboratory outcomes that are judged to be simulative of field loading conditions, models are developed for predicting permanent strain of compacted samples of local asphalt concrete mixtures after considering the stress level, properties of local material and environmental impacts variables. All in all, laboratory results were produced utilizing statistical analysis with the aid of SPSS software. Permanent strain models for asphalt concrete mixtures were developed as a function of: number of passes, temperature, asphalt content, viscosity, air voids and additive content. Mechanistic Empirical design approach through the MnPAVE software was applied to characterize rutting in HMA and to predict allowable number of loading repetitions of mixtures as a function of expected traffic loads, material properties, and environmental temperature.
Highlights
Various inconvenient types of distresses regularly impact on the asphaltic paving mixture during its service life
A curve is plotted for the loaded wheel for the test running, an examination of the graph can reveal the number of passes to failure, the maximum rut depth occurring
As shown in this Table the permanent deformation is highly dependent on temperature, Performance grade and air voids, while moderate and low for polymer content and asphalt content respectively
Summary
Various inconvenient types of distresses regularly impact on the asphaltic paving mixture during its service life These distresses are caused by construction practices, load, climate, and /or lacking materials. Permanent deformation may likewise start different types of asphalt pavement distress, for example, cracking, [4]. Such distress is related with the asphalt- cement binder and can be controlled essentially by modifying the binder material with chemical additives, [5]. The Mechanistic-Empirical Pavement Design Guide MEPDG is developed under the NCHRP a project represents a major advancement to pavement design and analysis It uses site specific traffic, climatic conditions and materials properties to predict rutting and cracking performance of flexible pavement structures, [8]
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