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原文传递 Concrete Bridge Deck Crack Sealing: An Overview of Research.

题名：	Concrete Bridge Deck Crack Sealing: An Overview of Research.
作者：	rahim, a. jansen, d. abo-shadi, n.
关键词：	methacrylate, cracking(fracturing), rebar, crack sealers, chlorides
摘要：	Cracking in concrete bridge decks is widely regarded as a long-term durability and maintenance problem that requires attention. It is a problem that occurs in most geographical locations and climates, and in many types of bridge superstructures. These cracks propagate through the deck allowing rapid ingress of moisture and chloride ions into concrete interior leading to excessive deterioration due to rebar corrosion. Popular measures to minimize rebar corrosion are to apply surface treatment sealers, which decrease the overall permeability of concrete, and/or to seal/fill the cracks to prevent the direct intrusion of chloride bearing water. In California, High Molecular Weight Methacrylate (HMWM) has been frequently used as crack sealers with millions of dollars spent annually on work involving Methacrylate applications on state owned bridges. While focusing on HMWM as a crack sealer/filler, the objectives of this research include: (1) A thorough review of previous research regarding the effectiveness of concrete bridge deck sealers; (2) A nationwide survey investigating the effectiveness of using Methacrylate as a sealer; (3) Developing guidelines concerning the use of HMWM along with other potential successful sealers. It was found that HMWM can be used as a crack sealer in conjunction with the use of silane as a surface sealer. A wide range of application temperature was reported in the literature. However, a range of application temperature between 7 degrees C (45 degrees F) and 29 degrees C (85 degrees F) is recommended. For new decks, it is recommended that HMWM be applied 3-6 months after construction to make sure that chloride concentration does not reach the corrosion threshold value. For old decks careful attention should be paid to the preparation method and the cleanness of both deck surface and cracks. It is recommended that HMWM sealer be applied every 4-5 years or as recommended by the bridge inspection team. For areas not subjected to deicing chemicals/chloride-laden environment, the use of HMWM as crack sealers can help restore the structural bond strength and the flexural strength, only if cracks are narrow and contaminants free. In the same areas and based on a parametric study employing Life-365 Model, the use of sealant to retard corrosion initiation in reinforcement steel is not significant. However, more laboratory/field investigations are recommended. / NOTE: Final rept. / Supplementary Notes: Prepared in cooperation with the State of California Department of Transportation. This final report covers March 15, 2005 through May 31, 2006. / Availability Note: Available on CD-ROM and in color paper copy. Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5285 Port Royal Road, Springfield, VA, 22161, USA.
总页数：	u0711；60p
报告类型：	科技报告