Characteristics of Asphalt Mixtures Made ​​with the Foam Bitumen Technology

In this paper an attempt is made to evaluate the engineering characteristics of asphalt mixtures made ​​with the foam bitumen. In this study, several tests were conducted on 90 samples to evaluate the effect of bitumen content, type of compaction, temperature and curing time on resilient modulus and density of the samples. Marshall and Gyratory compaction method was used to prepare laboratory specimens. According to the results, the ​​ resilient modulus values of mixtures compacted with Marshall Method has a higher density than mixtures compacted with gyratory compactor. The optimum bitumen content of mixtures compacted with Marshall Method are determined corresponding to the maximum density of the samples. To evaluate the Effect of bitumen, it was found that the sensitivity of mixtures prepared with Marshall Method to changes bitumen content is lower than Gyratory compacted samples. In Samples with no curing, resilient modulus of compacted samples by applying higher compacting energy (75 blows Marshall and Gyratory) is lower than mixtures compacted with 50 blow of Marshall. On the other hand, on samples curing in dry condition although the gyratory samples have higher density compare to marshall samples, but it was observed that the samples compacted by the Marshall compactor have higher resilient modulus. In addition in samples curing in wet condition, gyratory samples have higher resilient modulus in higher percentage of bitumen. Finally, due to the relatively low percentage of bitumen in asphalt mixtures made ​​with the foam bitumen, temperature changes in comparison with hot asphalt mixtures have lower effect on the resilient modulus.