This study is an investigation of the cause(s) of premature failure of latex modified concrete (LMC) bridge deck overlays in Ohio. Data and materials for 93 bridge decks overlaid with LMC were collected from five Ohio Department of Transportation Districts. Additional materials were collected and evaluations were conducted through monitoring the construction of seven LMC bridge deck overlays. Overall documentation and evaluation of the overlays and materials obtained are discussed; this includes field survey activities, construction monitoring and laboratory testing and analysis. Characteristics of the LMC mixtures and materials are evaluated and compared to acceptable standards. General findings were that most of the problems were due to the underlying old deck which was contaminated with chloride ions, previously undetected due to insufficient testing. Other conclusions are presented separately under construction monitoring, field surveys, and laboratory testing and analysis.