Influence of polymeric molecular chain structure on the rheological-mechanical behavior of asphalt binders and porous asphalt mixes

Abstract

This manuscript reports on two Styrene-Butadiene-Styrene (SBS) polymeric molecular chains so-called 1101AT and D0243, used to modify a 50/70 pen grade neat asphalt binder sample, generating the matrixes 60/85 E and Highly Modified Asphalt (HiMA), respectively. Some research gaps still exist and need to be investigated further, principally on why and how these distinct molecular chains influence the rheological-mechanical behavior of the asphalt binders and asphalt mixes, even pertaining to the same polymeric group. Dynamic Shear Rheometric (DSR) analyses describe the rheological spectra of the binder samples, considering the dynamic stiffness modulus in the complex plane |G*|. Porous asphalt mixes were evaluated considering the French formulation methodology and the following aspects: compaction ability, deleterious action of water, seepage speed and resistance to rutting. The results obtained indicate that HiMA matrix presented superior long-term rheological and mechanical behavior compared to 60/85 E, due to the more elaborate polymeric chain being associated to a bituminous matrix with rheological spectra providing less thermal and kinetic susceptibility, although its highest dynamic viscosity implies little reduction in the air void content and, consequently, lower seepage speeds to the porous asphalt mixes, but greater rutting resistance.