Experimental Study on Styrene–Butadiene–Styrene-Modified Binders and Fly Ash Micro-Filler Contributions for Implementation in Porous Asphalt Mixes

Styrene–butadiene–styrene copolymer (SBS) can be used to improve the mechanical and deformation properties of the binder used in its manufacture. However, the high cost of and variability in processing limit its performance. A secondary modifier to solve these problems is nano- and micromaterials that allow for the generation of unique properties in polymeric systems. Based on this, this study experimented with fly ash micro-filler (μFA) in low proportions as a binder modifier with SBS for use in PA mixes. The FA residue is considered in 3% and 5% dosages on a base binder with 5% SBS. Rheological results show that μFA improves classical, linear viscoelastic (LVE), and progressive damage properties compared with the modified binder. The PA blends with μFA reduce binder runout, resulting in a thicker film, thus showing better abrasion resistance in dry and wet conditions. Samples with μFA increase the post-cracking energy in indirect tension due to higher ductility. However, they decrease the fracture energy due to higher cracking before failure. In addition, μFA manages to decrease the difference between dry and wet ITS.