Evaluation of Sod Saver Blocks and M. C. Gill Panels for Tactical Bridge Access/Egress Applications

The purpose of this investigation was to evaluate the performance of Sod Saver Blocks and M. C. Gill panels when subjected to 2000 to 3000 passes of vehicle traffic with loadings up to and including 10 percent maximum military load class (MLC) 60 (later changed to MLC70) as stated in the Letter of Agreement (LOA) for access/egress surfacing. The Sod Saver Blocks and M. C. Gill panels were placed on a prepared clay (CH) subgrade having a CBR of approximately 1.4. Two separate tests were conducted on the Sod Saver Blocks. For test 1, the blocks were held together with 1/2-in.-wide nylon plastic-coated straps. For test 2, the blocks were held together with steel rings made from 3/16-in.- and 1/4-in.-diam. rods for items 1 and 2, respectively. Accelerated traffic was applied using an M54, 5-ton military truck loaded with 20,000 lbs for a gross load of 40,000 lbs and with tires inflated to 70 psi. An M48 tank was also used with a total gross load of 140,000 lbs. The tank traffic was applied intermittently with the truck traffic. All panels in both tests failed to satisfy the LOA requirements for an access/egress surfacing system with the M. C. Gill panels sustaining the highest number of vehicle passes with 67 percent of MLC 60 loading as required by the LOA.