Laboratory optimization of continuous blend asphalt rubber

Asphalt rubber from wet process requires batching blending and reaction time associated to blending rubber and conventional asphalt to produce asphalt rubber. The ideal blending of these materials depends on the combination of very important variables, such as the amount of rubber, reaction time and temperature reaction. This paper intends to optimize the laboratory production of asphalt rubber using the continuous blend process. The rubber from waste tyres was reduced by ambient grinding and the conventional asphalt used was the 5 0/70 pen asphalt, currently applied in Brazil mixtures. In order to obtain the desiderable asphalt rubber, nine asphalt rubbers were produced, varying the rubber content, reaction time and temperature. The asphalt rubber properties were evaluated through current tests: (i) penetration; (ii) softening point; (iii) resilience; (iv) apparent viscosity using a Brookfield viscometer. Additionally, the microstructure of the asphalt rubbers was evaluated by scanning electron microscopy (SEM)