Laboratory evaluation of geogrid-reinforced flexible pavements
Mohammadreza Sharbaf, Nader Ghafoori
Abstract
This study assessed the effectiveness of flexible pavements reinforced with two types of punched and drawn geogrids to reduce roadway base course thickness. Six laboratory tests were conducted using a steel cylindrical mold. Instrumentation included pressure cells placed at various locations of the test sections and a linear variable differential transformer which was placed on top of the loading system. A hydraulic actuator provided 40 kN (9 kips) cyclic load through a 305 mm (12 in) circular steel plate at a frequency of 0.77 Hz. Test results revealed that inclusion of both geogrid types in flexible pavement showed reductions in surface rutting and vertical stresses at the subgrade-base interface. Using the results for rutting depth, the use of geogrids increased the number of load applications by a factor of 1.5 to 7.5, depending on the test section properties and geogrid type, as well as the rutting depth experienced at various loading applications. Using the base course reduction values based on vertical stress results, the inclusion of geogrid in strong soil resulted in the reduction of base course thickness by nearly 7 percent.