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

Description

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

Ana Cristina Freire, Vítor Antunes, Fátima Batista
Laboratório Nacional de Engenharia Civil
Av. do Brasil, 101. 1700-066 Lisboa
acfreire@lnec.pt, vantunes@lnec.pt, fabatista@lnec.pt

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 section, and its mechanical behavior was evaluated on laboratory under different temperature conditions. 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, and addressing the climate changes, particularly regarding the heatwaves that periodically hit Portugal, several laboratory tests under different temperatures were performed. As a methodology to study the mechanical response 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 behavior 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 behavior of the mixture was determined in accordance with EN 12697-22.
The results obtained showed that the bituminous mixture with RAR applied in the wearing course on the test section presents adequate behavior in the tests performed, namely regarding fatigue and stiffness modulus when subjected to different test temperatures.

KEYWORDS: RAR test section, wearing course, bituminous mixture, mechanical behavior.