EXPERIENCES WITH BOUND AND NON-BOUND ROAD BASES - THE INTERPRETATION OF RECENT RESEARCH FINDINGS - PART 2

ERFAHRUNGEN MIT UNGEBUNDENEN UND GEBUNDENEN TRAGSCHICHTEN - AUSWERTUNG NEUER FORSCHUNGSERGEBNISSE. TEIL 2

In the research programme "Long term observations on selected sections of road", which the BAST and the Research and Material Testing Establishment for Construction at Stuttgart University are carrying out, the behaviour of a statistically large number of sections of road is being observed. These sections conform to standards for construction and the number and load of axle passes was recorded over several years. It is of interest that the deformation modulus e (index V2 value) on frost protection courses has increased compared with values recorded during the construction period. There are also increases in all sections investigated in the depth of lane indentation. Whether, and to what degree, these can be attributed to deformation or wear is yet to be established (core-extraction). The average rideability values in relation to the time lapse since construction tend to increase considerably for 4 groups of construction types uniformly if also differentially. Intermediate results for the investigation programme were supplemented by the works of V Becker, Luecke and Gerhardt on deformation behaviour and material parameters. It can be seen that an optimal combination of all the effects with non-bound courses results in higher performances than those obtained previously. Investigations by Brand and Luecke in addition to works not yet completed emphasize the great significance of mixing and laying on subsequent load capacity parameters and the dangers of segregation during laying. At present when assessing these results it can be said that when laying gravel courses with road finishing machines in 20 cm thicknesses, standards can be achieved far surpassing those predicted. An important area of research is that concerning water-bound road bases, dealing with such factors as laying technique, long workability period, possible immediate laying of subsequent courses, avoidance of cracking and reflection cracks in subsequent courses, the practicability of using slag, furnace sand, fly-ash, etc. Reference is made to the experiences in France and on research on the German Federal Motorway - Nuernberg to Munich - in which the construction method was made easier. Further tests are reported using cement-bound road bases of low quality materials in North Germany and Hessen. Finally a summary of those points is given which justify closer investigation. /TRRL/

  • Corporate Authors:

    Stein Verlag

    Geleitstrass 105, Postfach 54
    D-6050 Offenhach/M,   Germany 
  • Authors:
    • Nakkel, E
  • Publication Date: 1977-8

Language

  • German

Media Info

  • Features: Figures; References;
  • Pagination: p. 27-36
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00195184
  • Record Type: Publication
  • Source Agency: Bundesanstalt für Straßenwesen (BASt)
  • Files: ITRD, TRIS
  • Created Date: Aug 28 1979 12:00AM