Rapid field detection of sulfate and organic content in soils : technical report.

Details

• Creators:
  Harris, Pat ; Harvey, Omar ; Sebesta, Stephen
• Corporate Creators:
  Texas Transportation Institute
• Corporate Contributors:
  Texas. Dept. of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Soil stabilization
  • Soils by organic content
  • Sulfur
  • Soils--Sulfur content--Measurement
  • Soil stabilization--Measurement
• Publication/ Report Number:
  FHWA/TX-11/0-6362-1
• Resource Type:
  Tech Report
• Geographical Coverage:
  Texas
• Edition:
  Technical report; Sept. 2009-Aug. 2010.
• Corporate Publisher:
  Texas Transportation Institute
• Abstract:
  In recent years, the Texas Department of Transportation (TxDOT) has experienced problems chemically ; stabilizing moderate to high plasticity clay soils with calcium-based additives. Many of the problems are the ; result of soluble sulfate minerals in the soil reacting with the lime or cement added for stabilization. The ; occurrence of these deposits is unpredictable and often restricted to small areas. To address this problem, ; the researchers set about identifying a technique that provides a map showing the sulfate content of the soil ; over a large area to a depth of 3 to 4 ft. Two technologies were identified that provide an indirect ; measurement of sulfate salts (an electromagnetic device – EM-38, and a soil conductivity device – VERIS ; 3150). We tested these devices on three different TxDOT projects in different parts of the state that have ; been known for high sulfate contents. We collected soil samples at 1 ft intervals to a depth of 4 ft where the ; data varied. We measured the PI, moisture content, sulfate content, and organic content in each sample. We ; then ran multivariate statistical analyses to correlate the conductivity data collected with the VERIS 3150 to ; laboratory-measured soil properties. We observed that soil conductivity is related to the soil texture/clay ; content, moisture content, and dissolved salts (i.e., sulfate and other salt minerals). We noted that for all of ; the projects tested, a soil conductivity over 100 mS/m may contain problematic sulfate levels, but it may also ; be due to high plasticity clay soils and/or high moisture contents with other dissolved salts. What is ; noteworthy about this research is it provides a tool to intelligently decide where to collect soil samples to ; analyze for problematic sulfate levels versus the current method of collecting soil samples in a grid pattern of ; a specified interval that may be too large and not detect problematic sulfate levels until the road explodes.
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• Format:
  PDF
• Funding:
  Project 0-6362
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/20944/dot_20944_DS1.pdf
• File Type:
  [PDF - 4.93 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:467216fdb06c56eb9e9ec407a86f858007d82e852087bd08808e68ffab50497e06b3ea9f9cb812f6449baab2683675fd23cc0dc8e1f77139ff2205aa1b38e90d