This paper was presented at the `C-SHRP: Technical Insight Gained From the Canadian Long-Term Pavement Performance (C-LTPP) Project' session. The Canadian Strategic Highway Research Program (C-SHRP) conducted a research project aimed at better understanding and characterizing the seasonal behaviour of roads located in areas subjected to seasonal frost. For each of the 65 Canadian Long Term Pavement Performance (C-LTPP) test sections investigated, Benkelman Beam rebound (deflections) were measured during the spring and summer seasons. Four different pavement response indices were computed at each tests section, and then related to different factors (environment, materials, traffic and construction-related) believed to influence the temporal variation in deflections. The indices were computed based on uncorrected Benkelman Beam rebounds because it is felt that a temperature correction will mask the seasonal variations. A categorization technique was used to illustrate the various trends observed. Based on the observations made, it seems that in addition to temperature, the total road structure thickness, the subgrade frost susceptibility, freezing index and precipitation have the greatest influence on the seasonal deflection variations. Finally as a possible application of this analysis, all of the findings were synthesized and combined with the calculated pavement responsed indices to develop a correction table for use in pavement design, that accounts for the seasonal deflection variations. For various types of roads located in different climatic zones, correction factors are proposed to correct or adjust the average summer Benkelman Beam rebound. The detailed project results can be found in the final report entitled, "Seasonal Variation of Pavement Strength Based on Benkelman Beam Rebound", available from the Transportation Association of Canada (ISBN 1-55187-009-6). (A)
Abstract