Int. J. Forensic Engineering, Vol. 4, No. 1, 2018 1 Copyright © 2018 Inderscience Enterprises Ltd. Forensic study of premature failures with unbonded concrete overlay on interstate 70 in Ohio Junqing Zhu* Department of Civil Engineering, Ohio University, 102 Stocker Center, Athens, OH 45701, USA Email: jz157609@ohio.edu *Corresponding author Shad Sargand Department of Civil Engineering, Ohio University, 208 Stocker Center, Athens, OH 45701, USA Email: sargand@ohio.edu Roger Green Accelerated Pavement Load Facility, Department of Civil Engineering, Ohio University, Lancaster, OH 43130, USA Email: greenr1@ohio.edu Issam Khoury Department of Civil Engineering, Ohio University, 222 Stocker Center, Athens, OH 45701, USA Email: khoury@ohio.edu Abstract: This paper presents the results and findings from a forensic investigation initiated in 2014 to identify the causes of premature failures on an unbonded concrete overlay (UBCO) on Interstate 70 in Madison County, Ohio. This project was constructed in 1999 and 2000. Premature distress, including transverse cracking, corner breaks and slab settlement began to appear in 2008. Falling weight deflectometer (FWD) and distress survey data were collected from the field during the investigation. MIT Scan was used to evaluate dowel alignment. Concrete samples were taken from the field and tested in the laboratory. HIPERPAV was used to evaluate early behaviour of the Portland cement concrete (PCC). Results of finite element analysis was used to help understand the mechanisms responsible for the premature distresses.