SEDL / STP / STP1147-EB / STP24221S

Gyratory Evaluation of Aggregate Blends to Determine their Effect on Shear Resistance and Sensitivity to Asphalt Content

Ruth, BE
professor, University of Florida, Gainesville, FL

Shen, X
graduate research assistant, University of Florida, Gainesville, FL

Wang, L-H
graduate research assistant, University of Florida, Gainesville, FL

Pages: 13    Published: Jan 1992

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Abstract

Transverse and longitudinal shoving of asphalt paving mixtures is primarily related to the inability of current test methods to identify the properties of mixtures at different levels of traffic densification and the influence that aggregate properties have on the mixtures' resistance to plastic deformation (shoving). Research was conducted to investigate the use of the air roller equipped Gyratory Testing Machine for evaluation of asphalt mixtures containing aggregates from the same sources with varying amounts of crushed and natural sand aggregates (different blend proportions) to produce both identical gradations as well as different gradations. Analyses performed on the test results indicated overall excellent correlation between Gyratory shear (Gs) after 200 revolutions of densification and asphalt content (A/C), voids in mineral aggregates (VMA), and air void content (AV) at as-compacted densities. Similarly, statistical regression analyses indicated that asphalt, mineral filler, fine aggregate, and coarse aggregate contents have a significant effect on the Gs value for the different mixtures. As a result it is concluded that VMA and AV contents are not absolutely essential for mixture design or mixture evaluation. It is suggested that the GTM air roller procedure for testing of asphalt mixtures is probably all that is needed for evaluation of a mixture's resistance to plastic deformation.