The modification process of hot mix asphalts in which crumb rubber is initially mixed
with the mineral aggregates before the addition of the binder is known as dry process.
This process has as main advantages the use of conventional mixing plants and, at least in
principle, has no limitation of the incorporated rubber content. The aim of this paper is to
study the influence of the incorporated crumb rubber content in the mechanical behavior
of dense graded mixes ( grade envelope C of Brazilian specification DNER-ES 313/97).
For this purpose, laboratory tests were carried out to determine the main properties to be
used in numerical analyses of a structure of flexible pavement executed with that type of
asphalt mixture. The mechanical properties of asphalt hot mixes used in the numerical
analysis were determined by laboratory tests (stiffness modulus and fatigue life). The
studied asphalt hot mixes were produced with a crumb rubber obtained by the milling
process at ambient temperature and a straight binder AC 50/70 (classification by
penetration). The incorporated rubber content varied from 2% up to 3,6% in relation to
the mineral aggregate mixture. For the sake of comparison, a conventional asphalt
mixture produced with straight binder AC 50/70 and an asphalt-rubber hot mix produced
by wet process were also studied. The results showed that the asphalt hot mixes modified
with crumb rubber by dry process presented a significant improvement in terms of
mechanical behavior in relation to conventional asphalt hot mixes, especially in terms of
increase of fatigue life, as can be observed in the numerical analysis performed.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ).Cepsa.Biosafe.Bezerras Ltda
