ON THE COMPUTATION OF MASTER CURVES FOR BITUMINOUS MIXES

This paper describes a practical procedure for estimating the master curves for several properties of bituminous mixes e.g. dynamic stiffness, compressive strength and tensile strength. The procedure is based on the principle of time-temperature correspondence. The generalized sigmoidal model, which is based on physical observations, has been suggested to describe the master curves for these properties. The model parameters together with the activation energy parameter (delta H) of the Arrhenius equation can be obtained using non-linear least square regression techniques. In this contribution the validity of the generalized sigmoidal model to describe the master curves for those properties of asphaltic mixes is demonstrated. In addition, it is also shown that the delta H, which can be obtained from a rather quick (cheap) test e.g. indirect tensile test, can be used to estimate the master curves for other properties which are rather difficult or expensive to determine experimentally e.g. direct tensile test. The capabilities of the models have been tested by predicting different properties for 5 different asphaltic mixes within an error of +/- 15%, which is the same margin of error expected when testing asphaltic mixes due to their heterogeneous nature, sampling, and testing operations. For the covering abstract see ITRD E121480.