Performance of Drained and Undrained Flexible Pavement Structures under Wet Conditions Accelerated Test Data Test Section 544–Undrained

report contains a summary of the results and associated analysis of a pavement section composed of three lifts of asphalt concrete, untreated aggregate base, and subbase layers on top of a prepared subgrade. The pavement section is termed an " undrained pavement " because it does not include an asphalt treated permeable base (ATPB) layer between the asphalt concrete and untreated aggregate base layers. The pavement structure was designated Section 544. The tests conducted on this test section were performed as part of the Goal 5 Accelerated Test Program for the evaluation of drained (containing an ATPB layer) and undrained pavement under conditions of water infiltration. The main objectives of the test program are: 1. to develop data to quantitatively compare and evaluate the performance of drained and undrained asphalt concrete pavements under " wet " conditions. Wet conditions intend to simulate approximate surface water infiltration rates that would occur in a pavement with a badly cracked asphalt concrete layer along the north coast of California during a wet month. 2. to measure the effectiveness of the drained pavement versus the undrained pavement in mitigating the effects of surface water infiltration on a reduction in stiffness of the unbound layers 3. Additional objectives include: · to quantify elastic moduli of the pavement layers; · to quantify the stress dependence of the stiffness moduli of the pavement layers; xi · to determine the mechanism of failure of the pavement structure under these conditions · to evaluate the effectiveness of non-destructive and partially destructive methods for assessing pavement structural condition. HVS testing started in March 2000 and was completed in June 2000 after the application of more than 1.1 × 10 6 load repetitions. At the end of the test, the pavement section had 16 mm of surface rutting and a surface cracking density of 8.1 m/m 2. Chapter 2 describes the test program for Section 544. Design thicknesses for the pavement components were: asphalt rubber hot mix 40 mm dense graded asphalt concrete 162 mm aggregate base 274 mm aggregate subbase 305 mm Actual as-built thicknesses for the test section were: asphalt rubber hot mix 51 mm dense graded asphalt concrete 149 mm aggregate base 272 mm aggregate subbase 205–310 mm The test program was conducted in four stages as follows: • Stage 1: establish the initial structural condition of the section under conditions of no water infiltration • Stage 2: …