Impact of loading rate on asphalt concrete deformation and failure
The results for experimental determination of characteristics have been given and analyzed in this article for deformation and failure of an asphalt concrete at eleven loading rates from 0.000563 MPa/s to 0.652 MPa/s differing in 1158 times. A hot fine-grained dense asphalt concrete of type B prepared with a viscous bitumen of grade BND 100/130 which is traditionally used in road construction has been selected for the research. The tests have been performed at the temperature of 22–24 °C in a specially invented and assembled device according to the scheme of direct tension. The asphalt concrete samples had a shape of rectangular beam with dimensions 5×5×15 cm. It is found that from the moment of loading to the moment of failure the asphalt concrete is deformed nonlinearly. The rate of nonlinearity is increased with the load increase. Loading rate effects greatly the characteristics of deformation and failure of the asphalt concrete: failure time, specific work of deformation and failure deformation are decreased in 242, 160 and 3 times respectively at the loading rate increase in 1158 (nearly 1200) times from 0.000563 MPa/s to 0.652 MPa/s and the strength is increased in 5 times. Dependences for characteristics of the asphalt concrete failure (failure time, failure deformation, specific work of deformation and strength) on a loading rate are described with a high accuracy by power functions.