SAND BITUMEN MIXES AND HOT ROLLED ASPHALTS

This paper describes the use of the Marshall Test to compare the behavior of sand asphalts and hot rolled asphalts made with two types of sand, the particle layers and surface textures of which are representative of the extremes likely to be found in nature. Marshall Tests were also carried out on hot rolled asphalt mixes laid in Switzerland and Denmark, to compare the degree of compaction obtained on the road with that obtained by the Marshall compaction procedure. Results showed that 1. The Marshall method of mix design predicts the density of hot rolled asphalt surfacings, 2. The particle size distribution of a sand is the major factor controlling the packing properties of the sand, although the shape and surface texture of the sand particles play an important part, 3. The amount of bitumen required to produce a stable, durable mix is governed by the grading, surface textures and shape of the sand particle, 4. As the present BS594 specification specifies the properties of fine aggregates in terms of particle size distribution only, it is possible to produce mixes which are lacking in stability and durability. To overcome these limitations, it is suggested that the Marshall Test procedure be used to select the optimum binder contents of hot rolled asphalt. It is also suggested that the optimum binder content of hot rolled asphalt be chosen to be equal to the binder content at which the compacted aggregate skeleton is just filled with bitumen. /TRRL/

  • Corporate Authors:

    Building and Contract Journals Linited

    32 Southwark Bridge Road
    London SE1 9EX,   England 
  • Authors:
    • Duthie, J L
  • Publication Date: 1973

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Filing Info

  • Accession Number: 00083168
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Jul 2 1975 12:00AM