Mechanical evaluation of dense graded mixture prepared with asphalt-rubber in regard to the rubber content

Authors: Luciano Pivoto Specht, Jorge A. Pereira Ceratti, Lélio A. T. Brito



In Brazil, after 2001, approximately 700km of highways were paved using wet process to rubber incorporate (terminal blending), in the majority with use of dense graded mixes. This work presents a research which studies the mechanical behavior of dense mixtures prepared with different rubber contents in the binder (6, 12 and 8%) in comparison to a conventional mix. Asphalt-rubber was prepared in laboratory according to Mc Donald
mix process and sample preparation was designed in accordance to Marshall Methodology. Dynamic indirect tensile test (resilient modulus and fatigue @250C), indirect tensile test (tensile strength @250C) and permanent deformation (repeated triaxial loading test @450C) were carried out. An increment was observed in the design asphalt content with the rubber addition. Regarding the values of resilient moduli, it was noticed a decrease of this parameter with rubber content addition and it was also noticed an increase on tensile strength. The fatigue results showed the sensitivity of fatigue life to rubber addition. Finally, it was observed an inverse relation between rubber content and permanent deformation. The best performance was with those asphalt mixes with 12-18% of rubber content.

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