This research project deals primarily with statistically analyzing freezing index variation, frost depth prediction techniques and ensuing appropriate frost design changes. Data for these analyses are available from 14 field test sites across Pennsylvania which have been monitored monthly throughout the last 8 freezing seasons. Frost depths predicted by two theoretical methods and one empirical method are statistically regressed with actual maximum frost depths at the field sites. The sensitivity of the prediction to variations in the pertinent dependent variables are also considered. The best prediction technique for the Pennsylvania data set is chosen, and comments on obtaining realistic input variables are made. Measurements of the effects of differential heaving of the pavement system and of loss of subgrade bearing support properties of subgrade soils is important to proper strength Normalized pavement surface deflection measurements made (FHWA) subgrade support. Surface have measurements made with standard engineering survey levelling equipment are referenced to a "frost free" bench mark. Appropriate frost design changes are recommended as a result of the findings from the field test site data and from the Penn State Test Track research. An optimum thickness of subbase or replacement material for frost susceptible subgrade soil is suggested. The increase that the subase material provides

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Filing Info

  • Accession Number: 00316391
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-PA-RD-68-30-1 Final Rpt., FCP 45C2-222
  • Contract Numbers: 68-30
  • Created Date: Dec 30 1980 12:00AM