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Development and Layout of a Protocol for the Field Performance of Concrete Deck and Crack Sealants

出版	Midwest Regional University Transportation Center, 2009
URL	http://books.google.com.hk/books?id=fA06AQAAMAAJ&hl=&source=gbs_api
EBook	FULL_PUBLIC_DOMAIN

註釋The main objective of this project was to develop and layout a protocol for the long-term monitoring and assessment of the performance of concrete deck and crack sealants in the field. To accomplish this goal, a total of six bridge decks were chosen for study. The decks have ages that vary from 4 to 30 years old, are all in good condition, though some presented a variety of longitudinal, transverse and diagonal cracking. In each deck, test segments were laid out along one lane in four of the six bridges. Drill powder samples were extracted in each segment in order to determine the in-situ, near-surface chloride ion content of the deck. Laboratory analyses of the samples showed that the chloride ion content varied between 3.2 lb/cy for the younger decks (3 years old) and 20.8 lb/cy for the older decks (28 years old). Based on the recommendations of a previous laboratory investigation, a pool of the best performing deck and crack sealants were selected to be applied in the decks. In two bridges, deck segments were sealed with four deck sealants while one segment was left unsealed to be used as a control segment. Additionally, the cracks in each of these segments were sealed with five crack sealants. While two other decks were also scheduled for sealing as part of this phase of the project, they were not done because the required curing time for some of the products was longer than deemed acceptable by DOT crews for these high traffic bridges. It is recommended, however, that every effort be made to have these decks be sealed in the near future. The remaining two bridges had been sealed at the time of construction. While no specific information could be secured about the product used in these decks, the low chloride ion content in these decks suggested that the applied product has helped reduce the ingress of chloride ions. Therefore, it is recommended that these decks continue to be monitored over time. Based on the inspections and the data collected in the field, a protocol and schedule for the continuing monitoring of sealant performance is presented.