LABORATORY EVALUATION OF MODIFIED POROUS ASPHALT MIXTURES

Porous asphalt mixture (PAM) is mainly applied to the surface drainagelayer on high-speed trafficked highway pavements because it has manyapplication advantages such as : noise reduction and safety during rainfalldue to its open structure water is stored and moved horizontally within thelayer which reduces splash and spray effects and thus increases the visibilityof drivers during rainfall. On the other hand the major disadvantage ofporous asphalt layers are low stiffness , high rutting and durability .Theobjective of this study was to compare the influence of two modifier types(styrene-butadiene-styrene [SBS] and propylene modifier [PP]) on aporous asphalt mixture performance . The PAM evaluation was based on airvoids, asphalt flow drain down, and abrasion resistance at the mix designstep. The mix performance has been investigated by permeability, moisturesusceptibility, and rutting. The test results emphasized the importance ofusing the modifier in in minimizing the abrasion loss, reducing rutting andenhancing the durability of the PAC mixture. Porous asphalt mixturesprepared with 5 % SBS modifier were the most effective at increasing theabrasion resistance and reducing rutting; and the PP had no effect on themix strength.

کلیدواژه ها:

Asphalt flow drain ، polyprolene ، porous asphalt and styrene butadiene styrene