PCC Airfield Pavement Response During Thaw-Weakening Periods. A Field Study.
COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
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This investigation is part of CRREUs on-going characterization of pavement performance in seasonal frost areas. As part of the research, CRREL conducted several field studies for the Federal Aviation Administration FM on the response of airport pavements during thaw-weakening periods at three civil airports in Wisconsin, where the design freezing index in the area was around 900 to 1100oC-days and frost penetration ranged between 1250 to 2000 mm. This study focused on the performance of Portland Cement Concrete PCC pavements during the spring thaw-weakening period. The sites were instrumented with subsurface thermocouples and Falling Weight Deflectometer FWD tests were conducted during the spring thaw period at the center of the slab and across the joints. An analysis of the FWD data and backcalculation of the layer moduli using ILLIBACK and WESDEF was conducted. Unique relationships between the FWD deflections and the subgrade modulus and coefficient of subgrade reaction were obtained. Additional relationships were developed using the FWD deflections, PCC thickness and the horizontal tensile stress at the bottom of the PCC layer. A relationship between load transfer across joints and FWD deflections was also developed. On the basis of the relationships obtained in this study, a methodology for evaluating PCC pavements during spring thaw was developed. However, this methodology needs to be verified for other subgrade types and areas with other design freezing indices.
- Terminal Flight Facilities
- Civil Engineering