Evaluation of Semi-Circular Bend Test for HMA Specialty Mixes (BRIC, Hi-RAP and HPTO)

Semi-Circular Bend Test (SCB) is a new three-point bending test method with the ability to predict fatigue performance of HMA (hot mix asphalt) and is being considered by states across the US. New Jersey Department of Transportation (NJDOT) has been using the Overlay Tester (OT) for some specialty HMA mixtures to look at fatigue performance. The OT effectively simulates the reflective cracking mechanism of opening and closing of joints and/or cracks, but the specialized equipment necessary to perform the test is major areas of concern. The SCB is a test that possibly can be used as a quality control (QC) tool by the HMA supplier or as the NJDOT acceptance test. Depending on the actual test method, the SCB can be a simpler and less expensive test to run. Testing repeatability, sample preparation time, and field testing variations are concerns to be evaluated for ability to replace the OT with the SCB. The purpose of this project is to research and evaluate the different variations (temperature, notch dimensions, load rates, etc.) of the SCB tests that are being run by different states, develop a method for the comparison of fatigue performance results between the SCB and the Overlay Tester, and depending on the data and equipment cost, make recommendations.