Quantitative Microstructural Investigation of Deteriorated Reinforced Concrete Bridge Deck

Abstract

A reinforced concrete bridge deck located in Albion, Mich. was subjected to quantitative microcrack analysis for assessment of its health condition. Statistical sampling and quantitative microscopic techniques were used in the investigation. A dedicated software system was developed for image analysis of concrete planar sections and stereological analysis of data to quantify the (three-dimensional) microscopic system in concrete. The bridge deck under investigation was divided into three subregions with different (visual) damage conditions. Cores were extracted from different subregions using statistical criteria to ensure the adequacy of the number of cores. Some cores were used to determine mechanical properties of concrete; others were used for microstructural investigation. Two perpendicular sections were cut from the cores, and were prepared for environmental scanning electron microscopy. Statistical analysis of the quantified (spatial) features of the microcrack system revealed significant difference in concrete microcrack conditions between different subregions. The results emphasized the value of quantitative microscopy in assessment of the health condition of concrete based-infrastructure systems and the relation between microcracks characteristics and transport properties.