Quantification of cracks in concrete bridge decks in Ohio District 3

Abstract

"Report Date: February 2012."; Executive summary report (4 p.) laid in.; Includes bibliographical references (p. 58-61).; Final report;; Sponsored by: Ohio Dept. of Transportation; State job no. 134564The development of cracks in reinforced bridge decks is a critical problem, not only in Ohio state, but the whole of United States. Many bridge decks constructed within the last 10 years in Ohio have already shown varying levels and patterns of cracking. Bridge deck cracking is a serious issue because cracks allow harmful and corrosive chemicals to penetrate the concrete and deteriorate the reinforcing steel embedded in it, regardless of the bridge design type, length of spans, deck thickness and concrete mixture designs. Proper precautions need to be taken to avoid rapid deterioration of the bridges which can lead to increased maintenance costs and the need for possible replacement. The Ohio Department of Transportation's current procedure for bridge inspection requires periodic surveying of the whole bridge. However, this inspection procedure offers only a qualitative assessment of the bridges inspected. In this study, a quantitative measurement strategy was adopted by measuring the crack densities of twelve bridges in District 3. Two types of bridges were inspected: three structural slab bridge decks and nine stringer supported bridge decks. Crack densities were determined based on crack maps corresponding to the surveys for each bridge deck. The crack densities determined for the twelve bridge decks indicated that structural slab bridge decks have slightly higher shrinkage crack densities compared to the bridge decks constructed with stringer supports. However, the "structural" cracks seem to be wider for structural slabs (greater than 0.007 inch). Particularly on bridge ASD-42-0656, which is a continuous slab bridge, there were several large "structural" cracks that were parallel to the intermediate supports. These cracks were very wide (much greater than 0.007 inch). The shrinkage crack densities of the twelve bridge decks determined in this study were considerably lower than the crack densities of similar bridge decks located in other states, demonstrating that Ohio bridge decks in general have lower crack density than those in other states. The shrinkage crack densities of the bridges constructed with QC/QA type of concrete have lower values than the bridges made with other types of concrete