The Reclaimed Asphalt Pavement Addition to Produce Concrete Pavements

AUTHORS: Paglia, C.; Mosca, C.; and Anotonietti, S.

ABSTRACT: Durability issues increase the frequency of asphalt road surface course restoration on a longterm basis. Increased traffic loads, extreme environmental conditions and oxidation accelerate the deterioration of the asphalt pavements. A high amount of reclaimed asphalt pavements (RAP) is produced and only partially recycled in bituminous pavements. The increased stiffness of the old binder requires softer bitumen and adequate chemical preparation. Therefore, a relevant amount of material is still brought to disposal. In order to increase the use of RAP, RAP aggregates are mixed with cementitious materials to produce RAP concrete. In this work, RAP aggregates are added to 30% by weight in substitution of the natural rocky aggregate in plain (PCCP) and roller compacted concrete (RCCP) pavements. In spite of the inadequate laboratory compaction of the RCCP specimens, the mechanical properties of RAP concrete do not exhibit a significant difference compared with the 100 % natural aggregates specimens. Nevertheless, the technically low strength values did not allow further durability tests to be accomplished. On the contrary, the addition of RAP in conventional concrete shows a slight decrease in mechanical properties and modulus of elasticity, which are adequate for the pavement flexibility and for the reduction of the cracking susceptibility. The chloride and water permeability resistance are increased with the addition of 30% RAP, whilst the freeze / thaw resistance is lowered and merits further investigation in large field trials.