Use of Nevada’s Natural Pozzolans to Mitigate Alkali-Silica Reactivity
Alkali-silica reactivity is one of the most recognized deleterious phenomena in Portland cement concrete resulting in cracks, spalling, and other deleterious mechanisms. The aim of this study was (i) to assess the extent of reactivity of the aggregates, quarried from seven different sources, suspected of being conducive to ASR, and (ii) to compare the effectiveness of industrial (Class F fly ash) and natural pozzolans in mitigation of alkali-silica reactivity of the studied aggregates. To this end, seven aggregate sources, four natural pozzolan sources, and one source of Class F fly ash were used. ASTM Type V Portland cement was replaced at four levels of 15, 20, 25, and 30% by different pozzolan types and sources. A uniform water-to-cementitious materials ratio of 0.47 was used. Beam shaped mortars were tested for ASR-induced expansion for eight weeks. In addition, companion mortar cubes cured for 90 days in a salt-water environment and in a controlled moisture room were tested in compression. The findings of this investigation revealed that the ASR mitigation of the studied aggregates depended on the aggregate source, natural pozzolan source and content, and immersion age. For nearly all natural and industrial pozzolans used in this study, 15% by weight of Portland cement was sufficient to mitigate alkali-silica reactivity of the studied reactive aggregates. The loss in strength of the studied mortars also depended on aggregate and natural pozzolan types and sources, and reduced with increases in Portland cement substitution level. Overall, the four natural pozzolan sources used in this study exhibited similar to better performance, in comparison to that of the Class F Fly ash, in suppressing the alkali-silica reactivity of the reactive aggregates.
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Supplemental Notes:
- “This document was sponsored by the U.S. Department of Transportation, University Transportation Centers Program.”
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Corporate Authors:
Safety and Operations of Large-Area Rural/Urban Intermodal Systems Institute (SOLARIS)
Reno, NV United States 89557University of Nevada, Reno
Center for Advanced Transportation Education and Research (CATER)
Reno, NV United StatesUniversity of Nevada, Reno
Department of Civil and Environmental Engineering
Reno, NV United States 89557Nevada Department of Transportation
1263 South Stewart Street
Carson City, NV United States 89712Office of the Assistant Secretary for Research and Technology
University Transportation Centers Program
Department of Transportation
Washington, DC United States 20590 -
Authors:
- Ghafoori, Nader
- Kian, Arash
- Publication Date: 2019-2
Language
- English
Media Info
- Media Type: Digital/other
- Edition: Final Report
- Features: Figures; Photos; References; Tables;
- Pagination: 138p
Subject/Index Terms
- TRT Terms: Alkali silica reactions; Portland cement concrete; Pozzolan; Pozzolanic action
- Geographic Terms: Nevada
- Subject Areas: Highways; Materials; Pavements;
Filing Info
- Accession Number: 01700340
- Record Type: Publication
- Files: UTC, NTL, TRIS, ATRI, USDOT, STATEDOT
- Created Date: Mar 29 2019 10:20AM