Laboratory evaluation of hot asphalt mixtures containing Gilsonite and FORTA fibers and determination of economic benefits of their use in asphalt pavements

The growth of vehicle traffic in recent years in developing countries has led to an increase in the costs of road building and maintenance. Therefore, modification of bitumen properties is necessary due to the poor quality of bitumen. In this lab study, the relative performances of Gilsonite and FORTA fibers modifiers are evaluated. The bitumen tests conducted for this research are based on the addition of Gilsonite (0, 3, 6, 9, 12 and 15 % of made bitumen specimens), while the asphalt mixture tests are based on the addition of FORTA fibers (0, 0.3, 0.6, and 0.9% by weight of aggregate). The synergistic effect of adding both the additives as a composite additive on the relative performance of asphalt mixtures is also evaluated. The samples were tested for Marshall Stability and moisture sensitivity, while fatigue and dynamic creep tests were performed using the UTM machine. The results showed that only the use of Gilsonite as a modifier in bitumen significantly increases the Marshall Stability, fatigue resistance, the flow value resulted from dynamic creep tests and decrese moisture sensitivity of the asphalt mixtures compared to the use of FORTA fibers as a modifier in the mixture.