PREDICTION OF SUBGRADE MOISTURE CONDITIONS FOR PAVEMENT DESIGN PURPOSES

The results of regression analysis of subgrade moisture conditions have shown that there is a correlation between subgrade moisture content under the centre of a road, soil properties and annual evaporation. The results of testing of moisture station sites (1969-80) provided both centreline and edge moisture contents, the edge moisture contents being subgrade at a location 600 mm from the edge of the seal. These edge moisture contents were generally higher than centreline moisture contents and more highly variable. In an effort to characterise the nature of these edge moisture contents an 85th percentile moisture content was extracted and expressed as a ratio of the centreline 85th percentile moisture content. In a similar manner the mean moisture contents were analysed, as were the standard deviations. The mean ratio of edge to centreline moisture contents was found to be 1.14. The standard deviation of the edge moisture contents expressed as a ratio of the centreline moisture content standard deviation was found to be 1.22, i.e. The edge moisture conditions were more variable than the centreline moisture condition. It was also found that the 85th percentile moisture contents of the edge locations were greater than the centreline 85th percentile moisture contents. The final part of this report presents two regression equations that were calculated using the outer wheel path 85th percentile moisture content. (TRRL)

• Corporate Authors:

  Western Australia Main Roads Department, Australia

  Waterloo Crescent
  East Perth, West Australia 6000,   Australia 
• Authors:
  • BOTT, MLH
• Publication Date: 1980-2

Media Info

• Features: Figures; References; Tables;
• Pagination: 40 p.

Subject/Index Terms

• TRT Terms: Correlation analysis; Evaporation; Forecasting; Moisture content; Pavement design; Regression analysis; Subgrade (Pavements)
• Uncontrolled Terms: Centre; Side
• Old TRIS Terms: Wheel path
• ITRD Terms: 6401: Centre; 6527: Correlation (math, stat); 7183: Evaporation; 132: Forecast; 5920: Moisture content; 3055: Pavement design; 6588: Regression analysis; 9074: Side; 2950: Subgrade
• Subject Areas: Data and Information Technology; Design; Geotechnology; Highways; Pavements; I22: Design of Pavements, Railways and Guideways;

Filing Info

• Accession Number: 00325306
• Record Type: Publication
• Source Agency: ARRB
• Report/Paper Numbers: MED 80/8 Monograph
• Files: ITRD, TRIS, ATRI
• Created Date: Aug 15 1981 12:00AM