Comparison Between Flat Rubber Wheeled Loaded Wheel Tester and Asphalt Pavement Analyzer

Rutting has been identified as one of the primary distresses in asphalt pavement. Loaded Wheel Tester (LWT) has been widely used to evaluate the permanent deformation (rutting) of asphalt mixture. In China, a fat solid rubber wheeled LWT (FLWT) has been adopted by the highway design guide for many years. Dynamic Stability (DS), the number of load repetitions to generate 1-mm rutting during the last 15-min of one-hour testing, has been selected to characterize rutting of hot-mix asphalt (HMA). During the recent years, the Asphalt Pavement Analyzer (APA), has been introduced into China, and has gained popularity in pavement industry. APA uses final rut depth to evaluate the rutting performance of HMA, and there is no criterion for the APA rut depth for HMA design in China. In order to compare both data, a correlation between FLWT and APA test will be necessary. The present study selected seven mixtures commonly used in China and correlated the test results between FLWT and APA. The mixtures selected in this study included gyratory (Superpave) designed 25, 19 and 13-mm mixtures, dense-graded mixtures (25, 19 and 13-mm) designed with Marshall mix design method, and a 13mm SMA mixture. The result from this study indicated that a strong correlation existed between the FLWT DS and APA rut. depth for the mixtures studied. Recommended design criterion of APA rut depth was derived from the existing DS specification and the correlation developed between the FLWT DS and APA rut depth.