Marginal Aggregates in Flexible Pavements: Laboratory Evaluation.
Final rept. Oct 90-Aug 94,
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS GEOTECHNICAL LAB
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The purpose of this project was to evaluate the utilization of substandard or marginal aggregates in flexible airport pavement construction. This investigation was undertaken to evaluate the effects of using lower quality aggregates such as rounded uncrushed gravels and sands on the rutting of flexible pavements. The scope of this research project included a review of available literature and existing data Part I, a laboratory evaluation organized to determine the effects of marginal aggregates and potential techniques to upgrade these substandard materials Part II, and a field evaluation of these upgraded marginal aggregate asphalt mixtures Part III. This report summarizes the laboratory evaluation, Part II of the project. The laboratory investigation focused on three areas 1 aggregate characterization, 2 evaluation of asphalt mixture properties affecting rutting potential and pavement performance, and 3 upgrading marginal aggregate asphalt mixtures with hard asphalt cements and various asphalt modifications. The findings of this laboratory evaluation indicated that several test methods including the Particle Index, Uncompacted Void Content of Fine Aggregate, Unit Weight and Voids in Aggregate, and Gyratory Elasto-Plastic Index could be used to quantitatively characterize aggregate shape and texture. This laboratory study also demonstrated that the confined repeated load deformation triaxial creep test was successful in evaluating the rutting characteristics of asphalt mixtures. The laboratory data demonstrated that asphalt modification could improve the rutting characteristics of asphalt mixtures with marginal aggregates.
- Construction Equipment, Materials and Supplies
- Terminal Flight Facilities
- Test Facilities, Equipment and Methods