Temperature influence on mechanical behavior of a road pavement RAR test section

Abstract

The major function of the road pavements is to offer a proper surface that supports traffic loads, under suitable and safe conditions, during its service life. The pavement structure must be designed to ensure that, through its service life, the distresses do not go beyond certain limits, and therefore, minimum functional requirements are fulfilled. A bituminous wearing course was built on a test pit, and its long-term behavior was evaluated. The applied mixture was produced with RAR, a reacted and activated rubber (RAR), which is an elastomeric asphalt extender, developed by hot blending and activation of a rubber granulate with a designated bituminous binder and activated mineral binder stabilizer. As a major advantage of RAR, the ease of producing bituminous mixtures is mentioned allowing to be added into a batch plant (pugmill) or drum mix plant. Being aware that in-service performance of bituminous mixtures is related with the resistance to cracking, rutting, stripping, durability and other asphalt pavement distresses, several laboratory and in situ tests over time were performed. As a methodology to study the mechanical behaviour of the applied bituminous mixture, laboratory tests were performed. The stiffness test was performed by the four-point bending test (4PBT) using prismatic specimens and running frequencies between 0.1 Hz and 30 Hz, at a constant strain of 50 μm/m and temperatures of 10 °C, 20 °C and 30 °C according to EN 12697-26. The fatigue behaviour of studied bituminous mixture was evaluated by the 4PBT, under controlled strain and the application of a sinusoidal loading with different frequencies, according to EN 12697-24. The permanent deformation behaviour of the mixture was determined in accordance with EN 12697-22. Water sensitivity tests according to method A of EN 12697-12 were conducted to evaluate mixture behaviour under water conditions. The results obtained showed that the bituminous mixture with RAR applied in the wearing course on the test pit presents an adequate behaviour, namely regarding fatigue and permanent deformation.