SALT DAMAGE TO SOME PAVEMENTS IN ZIMBABWE

The blistering and cracking of the bituminous surfacing of four pavements in Zimbabwe are described and compared with similar damage in South Africa. In all cases the damage was caused by the accumulation of acid sulphate salts below the surfacing due to the use of economically available mining or industrial waste in the base or subbase. Evidence is presesented of production of salt within the subbase and seleted subgrade layers due to further oxidation in situ and of the migration of this salt to the surfacing. A new method of deriving salt limits for lower layers is suggested and used to derive a llimit for a local material. The salts causing the damage include pickeringite, hexahydrite, jarosite, copiapite, rozenite, and probably paracoquimbite and chalcanthite. Some of these have not been previously identified from salt-damaged pavements. Methods of prevention and repair of salt damage are suggested and it is believed that these very economic materials can give trouble-free performance provided certain precautions are taken. (Author)

• Supplemental Notes:
  • From the Proceedings of The Eighth Regional Conference from Africa on Soil Mechanics and Foundation Engineering, Harare, 1984, Vol 1.
• Corporate Authors:

  National Institute for Transport & Rd Res S Af

  P.O. Box 395
  Pretoria 0001, Transvaal,   South Africa 
• Authors:
  • Netterberg, F
• Conference:
  • From the Proceedings of The Eighth Regional Conference from Africa on Soil Mechanics and Foundation Engineering, Harare, 1984, Vol 1.
• Publication Date: 1984

Media Info

• Features: References; Tables;
• Pagination: p. 311-319

Subject/Index Terms

• TRT Terms: Acids; Base course (Pavements); Bituminous materials; Defects; Loss and damage; Pavement distress; Pavements; Prevention; Repairing; Salts; Subbase (Pavements); Subgrade (Pavements); Sulfates; Surface treating
• Uncontrolled Terms: Causes; Repairs; Subbase
• Old TRIS Terms: Bituminous surfacing
• Subject Areas: Highways; Pavements; Security and Emergencies;

Filing Info

• Accession Number: 00396699
• Record Type: Publication
• Report/Paper Numbers: RR 392
• Files: TRIS, ATRI
• Created Date: Aug 25 2004 2:37AM