Evaluation of the DC(T) Test in Discerning the Variations in Cracking Properties of Asphalt Mixtures

Abstract

As the temperature of an asphalt pavement drops to below freezing point, the asphalt material starts to lose its ductility, and consequently, the asphalt mixture becomes more susceptible to cracking. The disk-shaped compact tension [DC(T)] fracture test has been used to quantify the fracture properties of asphalt concrete at subzero temperatures for more than a decade. The Asphalt Institute laboratory has successfully utilized the DC(T) test in several research studies. As a result of these studies, a valuable database has been gathered which represents the sensitivity of the DC(T) test, and exhibits how the test is capable of capturing the effects of various factors on the performance of asphalt mixtures at low temperatures. This paper briefly presents the findings from some of these studies. The paper presents the response of the DC(T) test to the variations in several factors relative to asphalt pavements including the crude source of the asphalt binder, aging of the asphalt mixture, deficiency in the in-place density, pavement temperature, using a warm-mix agent, using RAP and RAS materials, and chip sealing as a preservation method. The test proved to be well capable of capturing the variations in these factors; therefore, it can be utilized by pavement managers to assess changes in specimens from asphalt pavements over time to help determine if any maintenance or rehabilitation action is required. Furthermore, the test can be used to evaluate laboratory-made mixtures and ascertain if they would perform satisfactorily in their designated environmental conditions.