Alkali-Silica Reaction Mitigation: State-of-the-Art
NAVAL FACILITIES ENGINEERING COMMAND PORT HUENEME CA ENGINEERING SERVICE CENTER
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This report gathers the state-of-the-art in alkali silica reaction ASR in concrete, and ASR mitigation techniques, in preparation for a more detailed study to be submitted to Congress in response to Public Law 106-398 HR 4205. Mitigation techniques from various states in the U.S., and from various countries and international organizations, were assessed and summarized. A set of recommended mitigation procedures was developed, which is being implemented in the current and upcoming Tri-Service guide specifications on concrete. In particular, the recommended methodology requires the replacement of cement by Class F or N fly ash 25 to 40 by weight, or ground granulated blast furnace slag GGBFS Grade 100 or 120 40 to 50 by weight, or a combination of both. The Class F or N fly ash should also have a maximum of 1.5 available alkali, a maximum 6 loss on ignition, and a maximum of 8 CaO. In addition to mitigating ASR, these cement replacements are expected to 1 reduce concrete costs, 2 significantly enhance the durability of concrete, 3 increase fly ash and GGBFS recycling, and 4 support the 1997 Kyoto protocol by significantly reducing CO2 production. If 25 of all cement were to be replaced, total savings to the United States economy could be in excess of 1 billion every year.
- Physical Chemistry