FACTORS IN BITUMINOUS CONCRETE DESIGN

This theoretical and experimental study of one-size (monovolume) and multisize aggregate particles was designed to develop physical factors for a unified characterization of dry aggregate particles of different types and sizes, and to relate these parameters with factors which would reflect the asphalt requirement for bituminous mixtures. The study also developed simple and practical techniques for measuring the aggregate parameters and to compare them with aggregate factors presently used in bituminous mixture technology. A practical procedure for estimating the optimum asphalt content in compacted bituminous mixtures is outlined. The results of this work with 8 widely different aggregates including one-size fractions and graded mixtures with one asphalt, indicate that the packaging volume concept for one-size particles provided a good theoretical basis for defining the physical, quantitative and measurable aggregate factors which characterize aggregates and bituminous mixtures and which can be used for a more basic and unified design of actual bituminous mixtures. The geometric factors of aggregate particles were unified by a single quantitative and basic parameter, the specific rugosity - S sub rv. Although theoretically, an accurate prediction of rugosity asphalt B sub ry from S sub rv is not possible, an estimate (for nonpourous aggregates) is possible in practice. The interaction between coarse and fine particles together with asphalt lost by rugosity and the macro surface voids of particles were found to be the most useful parameters for a unified design of multisize bituminous mixtures. Flow asphalt is the major factor unifying optimum asphalt conditions in bituminous mixtures. The variability of maximum stability of different types of aggregates was explained by the volumetric density of the active particles in the mixture. A sequence of measuring various parameters and a computerized procedure for calculating and setting up of mix design tables has been worked out.

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: p. 160-199
  • Serial:
    • Volume: 42

Subject/Index Terms

Filing Info

  • Accession Number: 00127328
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 16 1975 12:00AM