The optimum asphalt contents were determined based on the Marshall method. These tests are: Marshall Test, the indirect tensile test and the index of retained strength.
Laboratory tests were performed on specimens containing fiber with different lengths and contents. This paper work aimed through an experimental effort to assess the behaviour of asphaltic mixtures that fabricated by incorporating several dosages of carbon fiber in regard to the resistance potential of harmful effect of moisture in pavement. Moisture induced damage in asphaltic pavement might be considered as a serious defect that contributed to growth other distresses such as permanent deformation and fatigue cracking. The tolerances of filler gradation and mixing temperature are preferable to keep their current values. The optimum asphalt content tolerance can be increased to ± 0.5 %. The experimental results supported the recommendations to increase tolerances of coarse and fine aggregate gradations to ± 7.0 % and ± 5.0 % respectively. The resistance to moisture effect is investigated by conducting the compressive test for dry and water immersed conditions to find the index of retained strength. Marshall test is carried out to find stability and flow values. The evaluation process is illustrated by volumetric properties such as density, air voids, voids in mineral aggregate and voids filled with asphalt. All the tolerances specified in the specifications are taken into account, furthermore, the zones beyond these tolerances are also observed. The objective of this work is to evaluate the behavior of asphalt mixtures prepared by different aggregates gradations (12.5 mm nominal maximum size) that fabricated by several asphalt contents (40-50 grade) and various mixing temperature. The current Iraqi standard specifications for roads and bridges allowed the prepared Job-Mix Formula for asphalt mixtures to witness some tolerances with regard to the following: coarse aggregate gradation by ± 6.0 %, fine aggregate gradation by ± 4.0 %, filler gradation by ± 2.0 %, asphalt cement content by ± 0.3 % and mixing temperature by ± 15 oC.
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