SYMPOSIA PAPER Published: 01 January 1960

Influence of Chemical Composition of Asphalts on Performance, Particularly Durability


It is generally recognized that failures of asphalt pavements caused by embrittlement and other changes in physical properties during the aging process are due to chemical reactions of all or some of the asphalt components. This paper attempts to correlate chemical composition of asphalts with their performance as a binder and to demonstrate that changes in chemical composition parallel changes in performance.

The chemical analysis used in this investigation is the precipitation method by Rostler and Sternberg (1)2 which defines asphalts as consisting of five groups of components which can be isolated and tested as to performance, individually and as blends. The analytical method used is contrasted with four other methods proposed for chemical identification of asphalts. The laboratory tests used in studying performance are (1) abrasion resistance of Ottawa sand-asphalt mixtures before weathering and during various stages of weathering, and (2) cohesion of Ottawa sand-asphalt mixtures. Some conventional data such as used for specification purposes are also shown.

The data reported indicate (1) that chemical composition of asphalts is better defined by a precipitation method than by analytical procedures based on solution and adsorption equilibria, and (2) that physical, including rheological, properties of asphalts and changes of these properties during weathering can be correlated with changes in chemical composition. Laboratory prepared asphalts, commercially available asphalts, and asphalts extracted from cores from roads of known history were used in these tests.

Author Information

Rostler, FS
Golden Bear Oil Co., Bakersfield, Calif.
White, RM
Golden Bear Oil Co., Bakersfield, Calif.
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Developed by Committee: D04
Pages: 64–88
DOI: 10.1520/STP38773S
ISBN-EB: 978-0-8031-5600-5
ISBN-13: 978-0-8031-5599-2