Institute for Transportation

About the research

Reflective cracking is one of the most common types of distresses that occur in Iowa composite pavements—hot-mix asphalt (HMA) over jointed plain concrete pavement (JPCP), which constitutes over 50% of the entire Iowa Primary Highway System. It generally occurs early in the service life of the pavement. The ingression of water and moisture through the reflective cracks generally leads to the premature failure of the aggregate base and subgrade, and hence, they must be prevented. Although several techniques have been introduced over the years to reduce reflective cracking, the underlying mechanisms and causes of reflective cracking are not so well understood. A recently completed National Cooperative Highway Research Program (NCHRP) study (NCHRP Project 1-41) focused on developing mechanistic-based models for predicting reflection cracking in HMA overlays of flexible and rigid pavements and associated computational software for use in mechanistic-empirical procedures for overlay design and analysis.

The ultimate goal of the NCHRP Project 1-41 was to develop computationally efficient reflection cracking prediction software that could be used by highway agencies for routine HMA overlay thickness design and reflection cracking performance analysis of HMA overlay structures. The NCHRP 1-41 reflective cracking model was successfully integrated into the AASHTOWare Pavement ME Design (Version 2.2) released on August 12, 2015. However, the reflective cracking model in the Pavement ME Design has not been locally calibrated for Iowa pavement conditions.

The primary objectives of this research are (1) to investigate reflective cracking predictive models for Iowa highway pavements by evaluating and calibrating the recently integrated mechanistic-based reflective cracking model in Pavement ME Design and (2) to establish and recommend Iowa pavement performance threshold levels.