Evaluation of Modified Local Asphalt Mixtures by Fatigue Distress Criteria

Abstract

A fatigue is the accumulation of the materials damage in asphalt concrete mixtures and growing of cracks, under increasing effect of repeated vehicular loading, aging and environment factors, in this research study the effect of temperature, asphalt content, mineral filler, applied Strain, and the polymer (SBS) as a modified asphalt to evaluate their effect on fatigue crack. To achieve the objective of this research, the Nottingham flexural fatigue test is considered and superpave mix design requirements are employed. Test specimens of 380 mm length by 60 mm width and 50 mm height were sawed from slabs of the prepared mixes by rolling wheel compaction. Using Controlled-strain procedure,the tests were conducted at temperatures of 10-20-30 ±1°C and at a frequency of loading of 5 Hz. The full factor design as well, three asphalt contents 4.72, 5.22 and 5.72%, mineral filler (Portland cement, limestone dust), applied strain (400-750µs), and (2-4%) percent of (SBS) polymer, Local material properties, stress level and environmental impacts are considered for this aspect. From the result, it is observed that 2% of SBS modified mixture given a best result due to increase the percent of fatigue life to (120%) as the average when compared with the control mixture, the fatigue life has a positive relationship with asphalt content and temperature when using control strain .The fatigue life of the mixture with limestone dust have result more than mixture with Portland cement,In the general, The fatigue lifeof mixture at 400µs has given result more than 750µs.