Cracking and Linear Visco Elastic Binder Properties

The contribution of an asphalt binder to the cracking performance of a mixture is strongly influenced by information relating to the relaxation properties and stiffness. In the 1980s considerable interest existed in the relationship between the relaxation properties and cracking. The relaxation spectra can be captured by the R-value over a limited range of stiffness. This can be related to bottom up fatigue, durability and thermal cracking when the stiffness information is known. Analysis has been presented that demonstrates the interrelationship between parameters used in France, United Kingdom and the USA through linear visco-elastic modeling of a limited region of the master curve. This has been used in several studies recently and has been shown to be useful for judging material used in airfield, high RAP products and other additives in the asphalt market. The use of the linear visco-elastic methods can also lead to a better understanding of methods used to describe fracture—for example the Vialit pendulum test and the direct tension test. While these tests are conducted often in a non-linear region the data can be better explained when interpreting the stiffness results with a frame work developed by linear visco elastic considerations. The paper discusses some aspects of the techniques for development of master curves, interrelationships, linear visco-elastic properties and the relationships between the various parameters proposed for use in different countries.