Efeito da adição de polímeros reativo, não reativo e ácido polifosfórico e suas combinações nas propriedades de ligantes asfálticos.

Abstract

Asphalt polymer modification is used as an alternative to offset disadvantages of pure binder. The main classes of polymers currently used are: elastomers, plastomers and reactive polymers. The first two, improve binder properties, however, phase separation can occur during storage. Reactive polymers induce a chemical interaction with asphalt binder, impeding phase separation; however, the amount for modification is restricted to minimal quantities due to the risk of gelification of the binder. This research optimizes the use of reactive polymers – each with with unique beneficial properties – to produce high-performance elastomeric binders. The following modifiers were analyzed for this purpose: 1) reactive terpolymer (RET) of ethylene – metil acrilate – glycydil metacrilate (EMA-GMA), that provide elastomeric properties and aid chemical reaction with the binder; 2) polyphosphoric acid (PPA 166%), as a catalyst; and 3) high density polyethylene (HDPE), that increases stiffness at high temperature. In order to optimize the relative proportion of each modifier, a first stage of conventional testing – penetration, softening point, elastic recovery and rotational viscosity – was performed with binders before and after RTFO aging. From this step, the optimum amount of each polymer was identified. The second stage, using the optimum amount of modifier identified, involved the performance of mechanical tests of maximum strength, sensibility to water damage, resilient modulus, dynamics modulus, permanent deformation and fatigue test on mixtures designed according Superpave method. In addition, rheological tests of characterization of performance of modifiers to rutting and damage resistance were also analyzed. The results highlighted the efficiency of binder modification through the use of polymers. Various limits and amounts of each polymer were identified and are presented for use in high-performance elastomeric binders according to type of application.