Development of the saturation ageing tensile stiffness (SATS) test

This paper describes the development of a combined ageing/moisture sensitivity laboratory test to evaluate the performance of coated macadam binder course and base mixtures with relatively low binder contents and relatively high air void contents. The test is known as the saturation ageing tensile stiffness (SATS) test, and consists of initial saturation prior to placing compacted asphalt core samples in a high-temperature and high-pressure environment in the presence of moisture for an extended period of time. The stiffness modulus measured after the test divided by the stiffness modulus measured before the test (retained stiffness modulus), and the specimen saturation after the test (retained saturation), are used as an indication of the sensitivity of the compacted mixture to combined ageing/moisture effects. The test was used to reproduce in the laboratory the loss of stiffness modulus observed on a trial site where high modulus base (HMB) had been used. Two different aggregate types (basic and acidic...