PROPOSED NEW TESTS AND SPECIFICATIONS FOR PAVING GRADE ASPHALTS

Abstract

Asphaltic binders are highly important to asphaltic paving mixtures in providing a durable pavement. However, standard routine tests do not indicate, in a satisfactory manner, the required engineering properties, and a vast amount of research has been performed in an effort to improve this situation. Researchers have recently begun studying viscoelasticity theory to explain mechanical behavior of asphalts. The results of these studies simply confirmed a well known fact; namely, that the mechancial properties of an asphalt are dependent on the temperature and speed of loading. Recognition of these concepts has allowed a better understanding of required engineering properties for paving grade asphalts. In 1943, an initial progress report was presented on the authors' studies concerned with asphaltic materials. This paper gives results obtained since then and a tentative specification for paving grade asphalts that is based on standard and recently developed test methods.