Application of mechanistic empirical approach to predict rutting of superpave mixtures in Iraq

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.

Effect of Modified Asphalt Cement of the Performance of Stone Matrix Mixtures

“…The necessary mineral filler or Limestone is appended depending on the gradation criteria. The aggregate has been mixed in a mixing bowl (9700 g for plate specimen) and heated to the mixing humidity before mixing with the heated asphalt of each binder [23]. The compacted specimens were cooled at ambient temperature for 24 hours, 300 mm wide, (400 mm) deep and (40 mm) high.…”