There are many factors that affect the durability of Portland cement concrete (PCC), including the mix design and the materials used, the quality of construction, and the environment. Durability is not an intrinsic property of the concrete, but instead is related to how the material interacts with the environment. Durability-related deterioration is referred to as materials-related distress (MRD). Common MRDs include those caused by physical processes, such as freezing and thawing, or chemical processes, such as alkali-silica reactivity (ASR) and sulfate attack. This research project was undertaken to determine whether concrete used in the ADOT system is experiencing, or is potentially susceptible to, ASR or sulfate attack, and if so, to what degree.

The deck of the Sunshine Bridge overpass, located westbound on Interstate 40 (I-40) near Winslow, Arizona, was replaced on August 24, 2005. The original deteriorated concrete deck was replaced using high performance concrete (HPC), reinforced with low-carbon, low-corrosion reinforcing steel. HPC is a new technology in Arizona. This report documents the first survey of the deck's condition and recommends that ADOT embark on a monitoring program to evaluate the performance of HPC. The ADOT monitoring program should consist of visual observation of the deck condition and concrete sampling and testing to measure and document HPC performance. The survey presented in this report was performed on December 18, 2007, which represents the first field survey since concrete deck placement. Visual observation and test results show the following: 1. The concrete has a very low chloride permeability. 2. The concrete has significantly slowed down and/or prevented chloride penetration through the bridge deck. 3. The average air-void parameters of HPC do not meet the industry standards for frost resistant concrete. 4. The deck surface appears to have minimal wear from snow removal equipment and shows no signs of concrete cracking. HPC appears to perform very well during the monitoring period despite the lower than recommended air void system. There were no signs of deterioration or adverse field conditions. It is recommended that bridge deck monitoring and concrete testing be done annually or biennially throughout the bridge's estimated 50-year service life to confirm long-term performance of HPC. It is also recommend that the next monitoring survey be initiated and conducted before the end of the year 2009.