Simple Approach to the Investigation of Asphalt Mixture Strength on Small Beam Specimens at Low Temperature

In this research, a simplified approach based on size effect theory is used to extrapolate the strength values obtained on small asphalt mixtures specimens at low temperature with a modified bending beam rheometer (BBR). First, nine asphalt mixtures having different mix designs are prepared. Then, Weibull statistics and factorial design are used to evaluate the statistical distribution of the BBR measurements and the effect of conditioning time, loading rate, and testing temperature on material response, respectively. Finally, the BBR strength measured at three different temperatures is compared to the corresponding values obtained from two conventional test methods: direct tension (DT) and indirect tension (IDT) tests. It is observed that BBR strength values are statistically equivalent to those of IDT and DT when the size effect theory and the weakest link model are used to take into account the difference in volume, geometry, and stress field across the three testing methods.