DEVELOPMENT AND ANALYSIS OF LABORATORY TECHNIQUES FOR SIMULATING SEGREGATION

Objectives of this research were to develop laboratory techniques for simulating asphalt mixture segregation and determine mixture compactibility and physical properties. Segregation in asphalt concrete pavements occurs as a result of nonuniform distribution of the mixture components such as aggregate and asphalt. Mixture segregation can lead to premature pavement distress. Factors and steps in the production, transportation, and placement of asphalt mixtures associated with segregation include material type, mixture design, stockpiling and handling, plant type and operation, surge silos, truck loading and unloading, and laydown. Materials used in the study included gravel, natural sand, and an AC-20 asphalt cement. Aggregates were selected to meet the Indiana Department of Transportation specification for a No. 8 binder with a maximum aggregate size of 25.0 mm (1 in.). In order to simulate various degrees of segregation of the coarse and fine fractions, four artificially segregated asphalt mixtures were prepared in addition to the control asphalt mixture. As part of the study, specimens were compacted for the fine mixtures using the U.S. Corps of Engineers gyratory testing machine to determine the stability and compactibility indexes. Specimens were also prepared and tested using the indirect tensile test method. Slabs of the five mixtures were compacted using a laboratory linear compactor. Subsequently, these slabs were tested using the Purwheel tracking device to determine their rutting potential and moisture susceptibility. Results indicate that segregation affects the residual asphalt content, gradation, stability index, compactibility index, air voids, unit weight, indirect tensile strength, rutting potential, and moisture susceptibility of asphalt concrete mixtures.

Language

  • English

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: p. 36-45
  • Monograph Title: Hot-mix asphalt design, testing, evaluation, and performance
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00714831
  • Record Type: Publication
  • ISBN: 309061563
  • Files: TRIS, TRB
  • Created Date: Dec 4 1995 12:00AM