KOAC

A test procedure has developed where the crack growth parameters of an asphalt concrete mixture can be determined easily and uniformly. The semi circular bending (SCB) test is the basis of this procedure. However, in this procedure SCB-specimens with a base length of 225 mm are used instead of 150 mm as is indicated in EN 12697-44. In this way the total crack length increases and this is beneficial for the repeatability and reproducibility of the test results. The tests are force controlled with a haversine as loading signal. The length of the crack is measured indirectly by using a crack opening displacement (COD) gauge over the notch, which is situated in the centre of de base of the SCB-specimen. With finite element simulations, the relationship between the COD and the crack length and the stress intensity factor K are determined.All the information is used to determine the Paris’ parameters A and n of the tested mixture. The (draft) procedure has been used by two laboratories on two asphalt concrete mixtures. It is concluded that with the test procedure appropriate crack growth parameters can be determined with acceptable values for the repeatability and reproducibility of the test results.In the paper the test procedure will be presented. Also information on the tested materials and test results will be incorporated.KeywordsStress Intensity FactorCrack LengthCrack Opening DisplacementAsphalt MixtureCrack Opening DisplacementThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.