THE WARMBATHS FREEWAY ACTIVE CLAY ROADBED EXPERIMENT: PERFORMANCE AFTER SIX YEARS

A full-scale road experiment on the Pretoria-Warmbaths freeway in South Africa employing four different countermeasures against damage due to the highly active clay roadbed is described. Sections employing (a) replacement of the clay to a depth of 1.0 M, (b) pre-heaving by pre-wetting the roadbed with rainfall on a permeable gravel irrigation layer, (c) pre-wetting and tar shoulder membranes, and (d) 0.5 M replacement, pre-wetting and membranes, have performed very well for six years except for some culvert heave on the second and third solutions and some shoulder heave on the fourth. A control section employing no special precautions but the ordinary fill of which was also exposed to rainfall pre-heaved rather less, but gave comparable performance for five years before showing significant cracking. The riding quality of all sections remains at a psi of 4.0 or more. It is tentatively concluded that pre-wetting with rainfall on a permeable sand or gravel irrigation layer and no membranes, but with additional precautions at culverts and the avoidance of ponding during construction, is the minimum that would have afforded a satisfactory performance to date. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0858252198
• Supplemental Notes:
  • Proceedings of the Fifth International Conference on Expansive Soils, Adelaide, South Australia, 21-23 May, 1984.
• Corporate Authors:

  Institution of Engineers

  11 National Circuit
  Barton, A.C.T.,   Australia 
• Authors:
  • Netterberg, F
  • BAM, A
• Conference:
  • Proceedings of the Fifth International Conference on Expansive Soils, Adelaide, South Australia, 21-23 May, 1984.
• Publication Date: 1984

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 278-285
• Serial:
  • Issue Number: 84/3

Subject/Index Terms

• TRT Terms: Clay; Conferences; Cracking; Culverts; Durability; Experimental roads; Freeways; Gravel; Motion; Paved shoulders; Pavement base course; Pavements; Ponding; Riding qualities; Sand; Smoothness; Soil chemistry; Subgrade (Pavements); Swelling soils; Wetting
• Uncontrolled Terms: Membranes; Prewetting
• Geographic Terms: South Africa
• Old TRIS Terms: Active clays; Membranes (Biology)
• ITRD Terms: 4177: Clay; 8525: Conference; 5211: Cracking; 3360: Culvert; 5910: Durability; 3071: Evenness; 2778: Experimental road; 2916: Hard shoulder; 4525: Membrane; 2752: Motorway; 5483: Movement; 2955: Pavement; 2961: Roadbase; 8103: South Africa; 5203: Swelling (soil)
• Subject Areas: Bridges and other structures; Design; Geotechnology; Highways; Hydraulics and Hydrology; Pavements; I22: Design of Pavements, Railways and Guideways;

Filing Info

• Accession Number: 00389709
• Record Type: Publication
• Source Agency: ARRB
• ISBN: 0-85825-219-8
• Files: ITRD, TRIS, ATRI
• Created Date: Mar 29 1985 12:00AM