Functional testing of asphalt mixes on field samples

Abstract

The Norwegian research project PROKAS was conducted in 1998 – 2004. One objective was to develop performance-based specifications for Norwegian asphalt mixtures. As part of this project a number of samples were taken from different asphalt pavements in Norway. Material properties as stiffness and deformation resistance were examined using the indirect tensile modulus test and the indentation repeated load axial test. The tests were carried out on the Nottingham Asphalt Tester (NAT).
Results show that NAT seems to give reasonable E-modulus ranking of asphalt mixes, while there are great variations in the results from the deformation tests. Questions are raised if the used procedure for measuring deformation properties has to be adjusted/improved, or if another method can be more suitable.
These investigations have given useful experience regarding the material properties of different asphalt mixes in Norway. However, further laboratory testing on field samples has to be conducted before specifications are established.