Assessing the Impact of Various Modes of Compaction on Tensile Property and Temperature Susceptibility of Asphalt Concrete

Compaction has a significant influence on the performance of asphalt mixtures. Insufficient compaction leads to premature permanent deformation, excessive aging, and moisture damage. The optimum asphalt content was 4.7 % using Marshall Compaction method. Bulk density of (2.351) gm/cc was obtained at OAC with 75 blows of Marshall compactive effort as a benchmark. Same density was achieved using the other two techniques, Gyratory and Roller compactive efforts. Results indicate that (75) blows of Marshall Compaction, are equivalent to (148) gyrations in Gyratory Compactor with pressure of (600) KPa and angle of gyration of (1.25°), and they are also equivalent to (56) cycles in Roller Compactor at load (5) KN and vibration with air supply of (10) bar, to obtain the same density. A total of 162 Marshal Size specimens were prepared, using Marshall, and Gyratory Compaction techniques, based on OAC of 4.7 % with additional asphalt contents of 0.5% above and below the optimum value. Twelve slabs of (40 x 30 x 6.35) cm were constructed using Roller Compactor and (6) core specimens were obtained for each slab. All specimens were subjected to the Indirect tensile strength (ITS) at 25oC, 40oC, and 60oC, temperature susceptibility (TS), and tensile strength ratio (TSR) test for the three methods of compaction. The main objective of this study is to evaluate impact on the tensile and temperature susceptibility of compacted hot mix asphalt concrete (HMA) when using three methods of compaction to achieve same density.