Title:
Implementing Lessons Learned From Twenty Years of Bridge-Deck Crack Surveys
Author(s):
David Darwin, JoAnn Browning, Heather A. K. McLeod, Will Lindquist, and Jiqiu Yuan
Publication:
Symposium Paper
Volume:
284
Issue:
Appears on pages(s):
1-18
Keywords:
bridge decks, concrete construction, concrete mix design, cracking, shrinkage
DOI:
10.14359/51683803
Date:
3/1/2012
Abstract:
Cracking is a major durability problem for bridge decks. Studies in Kansas dating back 20 years that correlate the density of cracking with the concrete properties, construction procedures, and environmental conditions during construction provide specific guidance on the steps needed to limit cracking in bridge decks. Since 2002, the lessons learned in those studies have been successfully implemented through training and material and construction specifications as part of an 11-year pooled-fund study to develop aggregate, concrete, and construction specifications for low-cracking high-performance concrete (LC-HPC) bridge decks. Twenty-three bridge decks have been constructed using a combination of best practices, including a reduction in the cement paste content of the concrete while maintaining workability and finishability through the use of optimized aggregate gradations, maintaining adequate air content and moderate slump, deemphasizing the importance of high compressive strength and low concrete permeability, controlling the temperature of the concrete at the time of placement, providing improved curing, and reducing the rate of drying after curing is complete. The background and specifications for the study are presented, along with a description of field experience and crack survey results, which demonstrate that the procedures used for LC-HPC decks result in crack densities that are significantly below those observed in conventional bridge decks.