ABSTRACT
In this paper, a simplified approach based on size effect theory is used to extrapolate the strength values on small asphalt mixture beams obtained with a modified Bending Beam Rheometer (BBR) at low temperature. For this purpose, eleven mixtures having different mix design are first prepared. Then, the reliability of the measurements and the effect of temperature, conditioning time and loading rate on the material strength are addressed through Weibull statistics and factorial design on a representative set of mixtures. Finally, Indirect Tension (IDT), Direct Tension (DT) and BBR tests are performed at three different temperatures on the prepared asphalt mixtures and the strength results are initially found to be statistically different. Based on size effect theory and on the weakest link model, the strength values are transformed and further compared showing that BBR strength measurements are statistically equivalent to the values obtained with IDT and DT test methods.
