Accelerated Pavement Testing on Fayetteville Shale Roads

1. Accelerated Pavement Testing on Fayetteville Shale Roads Brady R. Cox, Ph.D. The University of Arkansas

2. Extent of Fayetteville Shale Deposits in Arkansas • Natural gas exploration and drilling in Fayetteville Shale deposits are rapidly expanding in magnitude and extent across the state • Heavy truck traffic associated with natural gas drilling activities is having a significant impact on roads that were not designed to carry these loads • The reduction in pavement life caused by heavy Fayetteville Shale drilling activities needs to be quantified on a road-by-road basis

3. Accelerated Pavement Testing with a Vibroseis Truck Servo-hydraulic dynamic loading system • Dynamic loads are applied to the pavement through a footprint the size of a single • pair of dual tires • The loads can be applied at any magnitude desired from approximately 2,000 – 18,000 lbs • peak force (9,000 lbs on a single dual tire footprint is approximately equal to an ESAL) • At a loading frequency of 30 Hz, over 100,000 cycles of load can be applied in one hour • The rutting profile is measured at various distances from the tire footprint (with LVDT’s) • as a function of applied load level and number of loading cycles

4. Rut Depth vs. Number of Loading Cycles from Accelerated Pavement Testing Number of Loading Cycles • Increased deformation due to heavier truck loads can be quantified on a road-by-road basis as a function of number of loading cycles • This information will allow • AHTD to estimate remaining • pavement life and the • incremental impact of heavy • truck traffic associated with • Fayetteville Shale drilling Light Load Vertical Deformation (Rut Depth) Increased deformation due to heavier truck loads Heavy Load