Stabilizing Sulfate-Rich Soils Using Traditional Stabilizers and Nontraditional Construction Methods: Case Study of State Highway 289 in Grayson County, Texas

Over the past 20 years problems with sulfate induced heave in pavements have surfaced around the world. This problem occurs when traditional calcium-based stabilizers, like lime or cement, are used to stabilize subgrade soils that contain sulfate minerals. The cause of the heaving is due to the formation of a mineral called ettringite, which requires four components to form. These include: the calcium available in the lime or cement, the aluminates available in the soil, the sulfate that occurs in several Texas soils and that is normally present in the form of gypsum, and, finally, water. Ettringite contains a large amount of water in its structure, and the formation of this can lead to increases in volume of up to 200 percent. Because of this, the Texas Department of Transportation (TxDOT) has limited the use of traditional, calcium-based stabilizers on construction projects where sulfate concentrations exceed 8,000 parts per million (ppm). Beyond that limit non-traditional additives must be evaluated for use, or the material must be removed and replaced with a select material with acceptable sulfate concentrations. The State Highway 289 Extension project was under construction in the fall of 2008 in Grayson County, Texas, when sulfate concentrations in the range of 30,000 to 50,000 ppm were encountered. Due to the limited availability of both non-traditional stabilizers and select replacement material, and after extensive laboratory testing, these sulfate-rich subgrade soils were successfully stabilized with lime using alternative construction techniques.

Language

  • English

Media Info

  • Media Type: DVD
  • Features: Figures; References; Tables;
  • Pagination: 9p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01155005
  • Record Type: Publication
  • Report/Paper Numbers: 10-1910
  • Files: BTRIS, TRIS, TRB
  • Created Date: Jan 25 2010 10:53AM