|
|
|
Title: EVALUATION OF SEASONAL VARIABILITY IN COHESIVE SUBGRADES USING BACKCALCULATION
Accession Number: 00731138
Record Type: Component
Record URL: Availability: Transportation Research Board Business Office 500 Fifth Street, NW Find a library where document is available Abstract: Seasonal variation in pavement strength is an important concern for engineers and transportation authorities. In 1990, an investigation was initiated that aimed at quantifying seasonal variations within a typical cohesive subgrade soil in Alberta. The study consisted of two phases: a field investigation phase and a laboratory testing program. The field phase involved instrumenting a pavement section that is representative of the primary highway system in Alberta with thermal conductivity suction sensors. Falling weight deflectometer (FWD) deflection tests were conducted at regular time intervals over a period of 2 years and at various locations within this section. Effective pavement layer moduli were backcalculated using measured deflections, and the results were plotted versus time to quantify seasonal changes occurring in pavement structural strength. Only the research findings obtained from the FWD deflection tests that deal primarily with subgrade moduli are discussed. Remaining field data represent a valuable resource to researchers investigating other pavement structural factors. Use of the backcalculation approach for quantifying seasonal variations in subgrade stiffness seems promising. Following a significant reduction in subgrade stiffness upon thawing, a long period of relatively constant strength prevails. After that a period of gradual recovery and subsequent increase in strength is experienced as freezing approaches. Backcalculated subgrade fill moduli were found to be 65% greater than their counterparts in cut areas. Furthermore, the subgrade fill moduli were observed to experience less seasonal fluctuation than the cut moduli. Finally, the backcalculated subgrade moduli were found to be insensitive to asphalt concrete surface temperature influences.
Supplemental Notes: This paper appears in Transportation Research Record No. 1546, Issues in Geotechnical Engineering Research.
Language: English
Corporate Authors: Transportation Research Board 500 Fifth Street, NW Authors: Khogali, WEIAnderson, K OPagination: p. 140-150
Publication Date: 1996
Serial: ISBN: 0309059518
Features: Figures
(12)
; References
(20)
; Tables
(3)
TRT Terms: Uncontrolled Terms: Geographic Terms: Old TRIS Terms: Subject Areas: Data and Information Technology; Design; Geotechnology; Highways; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces; I42: Soil Mechanics
Files: TRIS, TRB
Created Date: Feb 3 1997 12:00AM
More Articles from this Serial Issue:
|
