NON-CONVENTIONAL MATERIALS FOR IMPROVED SUBGRADES, CARBONIFEROUS RED SHALES, GRAVEL, SLAG, GRANULATED SLAG AND SPECIFICATIONS FOR THE USE OF NON-CONVENTIONAL MATERIALS IN PAVEMENT IMPROVED SUBGRADES

MATERIAUX NON TRADITIONNELS POUR SOUS-FONDATIONS, SCHISTES HOUILLERS ROUGES, GRAVES, LAITIERS, GRANULES ET REGLES DE BONNE PRATIQUE POUR L'EMPLOI DE MATERIAUX NON TRADITIONNELS DANS LES SOUS-FONDATIONS ROUTIERES

Carboniferous red shale, natural gravel and granulated slag were studied with a view to evaluating their possible use in improved subgrades to replace the sand normally utilized. Depending on conditions, the improved subgrade can have several functions: protection against contamination, protection against frost, drainage and stress distribution. Consequently the aptitude of a material to use in this layer depends on environmental conditions. As these materials do sometimes contain a large proportion of stones, methods of permeability measurement in a saturated state and measurement of suction curves were adapted to this high stone content. A permeater with an internal diameter of 50 cm, 50 cm high, gives sufficiently accurate measurements of the permeability of materials containing 6 cm stones. The suction curve is difficult to determine for the whole of the material, but it can be calculated from the capillary tension measured on samples prepared with different moisture contents and a material fraction not exceeding 12 mm. Sensitivity to frost was determined by means of frost tests to evaluate the materials durability, their brittleness, stability in the presence of water, and their content in soluble substances was also assessed. Results of this study show that neither red shale nor natural gravel nor granulated slag are ideal materials for improved subgrades. Each has a defect(s) which limit(s) its possibility of utilization. However in some specific conditions described here they can be used successfully. (TRRL)

  • Corporate Authors:

    Road Research Centre, Belgium

    Boulevard de la Woluwe 42
    B-1200 Brussels,   Belgium 
  • Authors:
    • GORLE, D
  • Publication Date: 1978

Language

  • French

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: 159 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00323389
  • Record Type: Publication
  • Source Agency: Centre de Recherches Routieres (CRR)
  • Report/Paper Numbers: CR 9/78 Monograph
  • Files: ITRD, TRIS
  • Created Date: Jun 12 1981 12:00AM