Updates to CalME and Calibration of Cracking Models

The CalME flexible pavement simulation and design software program has been completely recoded as a web-based application calledCalME 3.0. CalME 3.0 retains the same incremental-recursive damage approach and the same forms for damage models and transferfunctions as CalME 2.0, which was validated using accelerated pavement testing data from Heavy Vehicle Simulator (HVS) test sectionsand the WesTrack experiment.The following enhancements and additions are all included in the revised program. First, the old software’s fatigue cracking transferfunctions for hot mix asphalt (HMA) on aggregate base, cement-stabilized bases, and portland cement concrete have been recalibratedusing a new approach for the calibration of mechanistic-empirical pavement design methods; this approach uses “big data” frompavement management systems, explicitly and separately considers between-project and within-project variability, and uses tens tohundreds of times more performance data than are used in conventional calibration methods. Second, the updated program also includesnew damage models and transfer functions for in-place recycling materials, including full-depth recycling (FDR) with foamed asphalt pluscement and cement stabilization, and partial-depth recycling (PDR) with emulsified asphalt and foamed asphalt plus cement. Third, theprogram now has been given the ability to model PDR using cold central plant recycled (CCPR) materials. Fourth, new damage modelshave been introduced for cement-stabilized bases and cement-stabilized and lime-stabilized subgrade materials to correct problems withthe models in CalME 2.0. Fifth, minimum aggregate base thicknesses were developed based on calculations of permanent deformationunder construction traffic. Lastly, simplified methods were developed for estimating subgrade stiffnesses (resilient modulus) based ondynamic cone penetrometer (DCP) tests, California bearing ratio (CBR) tests, and R-value tests.It is recommended that CalME 3.0 be implemented for pavement design, that the calibration be updated with new data approximatelyevery 3 to 5 years, that Caltrans traffic databases be checked before they are used again for recalibration, and that use of the recently updated Caltrans DIME database of as-built data be considered for future calibrations.