Seasonal variation of temperature and moisture cause considerable changes in the load-carrying capacity of pavements in geographical areas subject to extreme freeze/thaw conditions. Pavement engineers in these areas must be able to quantify the variation in the load-carrying capacity of a pavement in order to design it adequately. The Seasonal Monitoring Program (SMP) of the Long Term Pavement Performance (LTPP) study of the U.S.A. Federal Highway Administration (FHWA) is monitoring seasonal variations in Falling Weight Deflectometer (FWD) deflections, air temperature, rainfall, soil temperature, moisture content, and soil electrical resistance at numerous sites across North America. The present study relates changes in pavement load carrying capacity represented by the pavement layer resilient moduli to selected environmental factors on the SMP site near Oak Lake, Manitoba. The most significant environmental parameters causing seasonal variation in pavement layer resilient moduli are identified as surface temperature (asphalt layer) and Thawing Index (base and subgrade layers). The examination of the material properties of this single pavement site during any time of the year is an important first step towards the adoption of mechanistic pavement design and rehabilitation procedures at the Manitoba Department of Highways and Transportation. (A)
Abstract