Sound absorption is a material property which contributes to reduce noise levels when sound
propagates from the source to the receiver. Porous materials have particularly good
absorption characteristics, not only because of the high percentage of air voids, but also due
to their flow resistance and tortuosity. Road surface layers made of gap graded mixtures are
among those absorptive materials. Because these mixtures have a void content that may be
considered of medium level, this study aims to characterise their absorption capacity,
particularly of those with rubberized asphalt binder. For this purpose, absorption
measurements in a Kundt’s tube were performed on cores extracted from slabs with different
gap graded asphalt. In order to study the effect of the rubberized asphalt, the mixtures were
produced in laboratory with two types of rubberized asphalt and with unmodified asphalt. The
effect of the binder was pondered with this procedure. Furthermore, the effect of porosity was
considered bycomparing the results of mixtures which have considerably high and low void
contents.(undefined
