mechanical properties of non-woven polyester fibers and polymer-modified bitumen composites

blown bitumen (110/10) was mixed with heavy vacuum slops (h.v.s), 60/70 penetration grade bitumen and recycled isotactic polypropylene (ipp) at different levels. the resulting resins were used to impregnate non-woven poly(ethylene terephthalate) fibers to form composites. the modulus and penetration grade of the resulting bituminous resins were determined. it was found that these bituminous resins drastically affect the modulus of the composites formed by low-young’s modulus fibers such as polyesters. consequently, interactions between resin and fibers and the correlation length of asphalthenes (in absence of ipp) and interdiffused coalescence and segregated network of asphalthenes (in presence of ipp) result in a non-linear behavior of composite’s modulus. the behavior of the composites with or without ipp is controlled by resin toughness and resin interactions with the fiber through the viscosity. comparison of the experimental composite modulus data with the theoretical modulus data revealed that the takayanangi’s model best predicts the behavior of these composites. the adjustment factors of this model were reported and proposed as an indication of fiber-resin interaction. it was also found that the modulus of fibers is affected by toughness, viscosity and the ipp content of the bituminous resin.