Study On The Performances Of The Re-Recycled Asphalt Mixture

Currently, under the policy environment-friendly society, people’s awareness of environmental protection is growing. The aggregates production process has an environmental damage as well the production of high quality aggregates remained a problematic for the construction of the asphalt pavement. Extensive research has been carried out on the recycled asphalt pavement all over the world. However most of the undertaken researches were done on the once recycled asphalt pavement whereas the study on the re-recycled asphalt pavement is relatively small and mostly based on an asphalt mixture performance. But it’s undeniable that, a large number of the recycled pavement will soon get to the end of their service life so it appear to be a must to solve the problem of the re-recycled asphalt pavement. This thesis addressed the re-recycled asphalt pavement research issues, mainly from the chemical composition, microstructure and viscoelastic properties of the different blended binders in which the proportions were determined using the fitting data on an exponential function. And through re-recycled asphalt mixture laboratory tests to verify the re-recycled asphalt Mixture pavement performance.Firstly in the light of studying how to heal the re-recycled asphalt binder two different materials were used(New asphalt binder 110 号) and a particular rejuvenator).In the first case where the blends include the re-recycled binder and the new asphalt binder, using the empirical test data fitting parameters on an exponential function, a defined proportions of the different binders in the blend were determined(110+20%RAP; 110+40%RAP).In the second case the defined percentage of rejuvenator was added to the re-recycled asphalt binder. Secondly the different obtained binders were submitted to different tests to confirm their performances as an asphalt pavement materials. Hence the rheological properties of the different materials using the DSR frequency sweep test under different temperatures(10°C; 20°C; 30°C, 40°C; 50°C and 60°C) was conducted, which revealed that the rejuvenated binder performed more well at intermediates temperatures comparing to the different old-new blended binders. Also in the light of evaluating the different binders low temperature performance the thermal analysis was conducted using DSC test, from which and based on the Tg values, the rejuvenated binder exhibits a more brittle nature than other asphalt blends. Besides the microstructure analysis(morphological and mechanical properties) of the different binders informed on the effect of the new asphalt binder and the rejuvenator on the re-recycled asphalt binder. The different mechanical properties(adhesion; dissipation energy and DMT modulus) maps for the different blends consist of similar patterns as those from AFM intermittent-contact mode, what actually indicate that morphological characterization for these samples was repeatable and that complete blending between the different blended binders was achieved. Also it was seen that the mechanical properties from microscopic measurements of adhesion and dissipation were consistent with the macroscopic DSR results(The more the new asphalt is in the blend the higher the adhesion and dissipation energy become, however the rejuvenated binder developed higher adhesion and dissipation comparing to the others blends),Also after the adding of the new asphalt binder in the RAP binder the modulus decreased, so become less stiff and get to their recovery even though the rejuvenator seem to recover better the RAP binder than the new asphalt binder.Finally After ample analysis of the materials different new mixtures were performed(old-new asphalt mix and old-new +rejuvenator mix).Mixtures in both the cases were subjected to marshal test, splitting tension strength test, and rutting test which actually informed about what will be their performances in the field. Hence the old-new mixture developed higher stability while the rejuvenated mixture is more moisture susceptible. Also the old-new mixture resist better the deflection and provided a higher shear resistance, from what we can conclude that they also performed well at high and intermediate temperature. The whole work of this thesis lead to know more about the re-recycled asphalt pavement and since it has something to do with the multiple recycled asphalt pavement, some conclusions and recommendations were done in the light of helping in the future researches concerning this particular area that remained of great importance for the asphalt industry.