Applicability of adding sisal fibers to SMA asphalt mixtures

Stone Matrix Asphalt - SMA is a mixture with a high proportion of coarse aggregates and a high content of asphalt binder to fill the voids formed in the structure. Fibers or modified binders are usually added to the mix in order to prevent excessive run-off of the binder. This work studied the addition of Sisal fibers to SMA mixtures, with liquid absorption and high temperature stability being properties of these fibers, which suggests that they can be used in hot mixes. The results indicated that the fiber reduces binder run-off and the addition in different proportions with a length of 15 mm showed improvements in mechanical properties, such as an increase in Tensile Strength and Retained Tensile Strength that exceeded the minimum required for SMA mixtures. The fiber proved to be a suitable material to be used in asphalt mixtures and showed great capacity to prevent excess run-off of the binder.