Temperature Correction of Backcalculated AC Modulus (0-1863-S)

The Texas Department of Transportation (TxDOT) uses the falling weight deflectometer (FWD) for pavement evaluation. A common application is the backcalculation of pavement layer moduli by deflection basin fitting. In Texas, pavement engineers use the MODULUS program to provide estimates of pavement layer moduli from measured FWD deflections. These estimates are subsequently used in other applications, such as the FPS-19 flexible pavement design procedure, the Program for Analyzing Loads Superheavy (PALS), and the Program for Load-Zoning Analysis (PLZA). For pavement applications, engineers must adjust the results obtained from the FWT) or correct them to reference or standard conditions of temperature, moisture, and loading frequency. As indicated in the research project statement for Project 0-1863, this problem has been studied by state, federal, and international researchers. What is needed is to use the knowledge gained from previous studies to develop an automated method for correcting FWD data to standard conditions. The scope of the project was imited to asphalt concrete (AC) pavements with unbound base materials, and to the development of an automated procedure for correcting backcalculated AC modulus to user-prescribed reference or standard conditions of temperature and loading frequency.