Laboratory and in-situ tests for estimating improvements in asphalt concrete with the addition of an LDPE and EVA polymeric compound

Pavement deformation is a critical issue in the design of pavement structures and the related mixture. Asphalt concretes may be very sensitive to this problem, in compliance with the viscoelastic behaviour of the adopted bitumen. To improve the material performance, many attempts have been made to introduce in the mixture other materials as “modifiers” or “additives” for increasing the permanent deformation resistance and the elastic modulus of the material. Among the different possible materials, polymers determined significant improvements in the road pavement performance. In this paper, the authors tested the adoption of a specifically engineered polymeric compound, in order to evaluate its effects on a generic asphalt mixture. Several tests were used to prove the effectiveness of the modification. Tests were performed not only in the laboratory, but also in an actual pavement section of the International Airport of Palermo in Sicily. Tests results prove that a proper mix-design can assure a decrease in the permanent deformations, remarkable growth of the material modulus with a reduced bitumen percentage, with economical savings. Finally, regarding fatigue resistance, the modified mixture with low bitumen content assures performance comparable to the control mix containing higher bitumen percentage. Then, the proposed application can be very useful to improve pavement performance even when using softer binder, easier to find in the Italian context.