ISSN: 0149-6115
Published Online: 22 September 2009
Page Count: 10

Laboratory Evaluation of Geogrid Base Reinforcement and Corresponding Instrumentation Program

Chen, Qiming
Research Associate,Louisiana Transportation Research Center, Louisiana State Univ.,LA,

Abu-Farsakh, Murad
Research Associate Professor,Louisiana Transportation Research Center, Louisiana State Univ.,LA,

Tao, Mingjiang
Assistant Professor,Dept. of Civil and Environmental Engineering, Worcester Polytechnic Institute,MA,

(Received 9 December 2008; accepted 20 August 2009)

Abstract

The performance of geogrid base reinforcement in pavement on weak subgrade under cyclic plate load testing was studied. The performance of instrumentation sensors was also evaluated to improve future instrumentation programs. The tests were conducted inside a test box of dimensions of 2.0×2.0×1.7 m³ using a servo-hydraulic actuator. A 40-kN load at a frequency of 0.77 Hz was applied through a 305-mm-diameter steel plate. The sensors used included linear variable displacement transducers, pressure cells, bondable foil strain gages, and piezometers. The test results showed that the inclusion of geogrid at the subgrade/base course layer interface can significantly improve the performance of flexible pavement on weak subgrade (California bearing ratio=0.5 %) and that the traffic benefit ratio can be increased up to 3.5 for a rutting depth of 25 mm. The test results also showed that the reinforcement can redistribute the applied load to a wider area, thus achieving an improved stress distribution on the subgrade, which will eventually reduce the permanent deformation of subgrade. The bondable foil strain gages are unsuitable for long-time continuous monitoring of strain development within geogrid under high number of cyclic loading.

Keywords:
geogrid, flexible pavement, cyclic plate load tests, instrumentation, traffic benefit ratio

Paper ID: GTJ102277
DOI: 10.1520/GTJ102277
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