Over deze norm
NEN-EN 12697-25 specifies three test methods (A1, A2 and B) for determining the resistance of bituminous mixtures to permanent deformation by cyclic compression tests with confinement. The tests make it possible to rank various mixtures or to check on the acceptability of a given mixture. They do not allow making a quantitative prediction of rutting in the field to be made. Test methods A1 and A2 describe methods for determining the creep characteristics of bituminous mixtures by means of a uniaxial cyclic compression test with some confinement present. In this test a cylindrical test specimen is subjected to a cyclic axial stress. Method A2 is preferred for mastic asphalt and Method A1 for other asphalt mixtures. To achieve a certain confinement, the diameter of the loading platen is taken smaller than that of the test specimen. In test method A1, the test specimen is loaded by block-pulses whereas in method A2 haversine loading with rest time is applied. Test method B describes the method for determining the creep characteristics of bituminous mixtures by means of the triaxial cyclic compression test. In this test a cylindrical test specimen is subjected to a defined confining stress and a cyclic axial stress. This test is most often used for the purpose of evaluation and development of new types of mixtures. This European Standard applies to test specimens prepared in the laboratory or cored from the road. The maximum size of the aggregates is 32 mm.