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Primary Topic: Materials-Concrete
Description: Alkali-silica reaction (ASR) is a significant durability problem that has resulted in premature deterioration of various types of concrete structures in the United States and throughout the world. Although several viable methods exist to prevent ASR-induced damage in new concrete structures, very few methods mitigate further damage in structures already affected by ASR-induced expansion and cracking. Lithium compounds have been recognized for more than 50 years as effectively preventing expansion caused by ASR, and there has been renewed interest in recent years in using lithium compounds as either an admixture in new concrete or as a treatment of existing structures. This report is intended to provide practitioners with the necessary information and guidance to test, specify, and use lithium compounds in new concrete construction, as well as its use in repair and service life extension applications. This report replaces the previous report (Guidelines for the Use of Lithium to Mitigate or Prevent ASR, Folliard, et al., 2003) and includes significant changes, especially those related to recommendations for testing and specifying lithium compounds.
This report provides a basic overview of ASR, including information on mechanisms, symptoms of ASR damage in field structures, mitigation approaches, test methods, and specifications. A comprehensive summary of lithium compounds is provided, including information on their production, availability, and use in laboratory concrete studies and field applications (including a range of case studies). Guidelines for using lithium compounds as an admixture in new concrete and for treating existing structures suffering from ASR-induced damage are presented, including information on how to assess the efficacy of lithium compounds in laboratory tests. Some basic information also is provided on the economics of using lithium both in new concrete and as a treatment for existing structures. A summary of conclusions is included and identifies several technical and practical issues that should be considered for future laboratory studies and field applications.
FHWA Publication Number: FHWA-HRT-06-073
Publication Year: 2006
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