Carbon Fiber-Reinforced Polymer Concrete Masonry Unit Bond after 20 Years of Outdoor Exposure

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Title: Carbon Fiber-Reinforced Polymer Concrete Masonry Unit Bond after 20 Years of Outdoor Exposure

Author(s): Mostfa Al Azzawi, Philip Hopkins, Joseph Ross, Gray Mullins, and Rajan Sen

Publication: Structural Journal

Volume: 115

Issue: 4

Appears on pages(s): 971-982

Keywords: bond; carbon fiber-reinforced polymer (CFRP); concrete masonry unit (CMU); durability; exposure; masonry; nondestructive; pulloff

Date: 7/1/2018

Abstract:
Two full-scale concrete masonry walls were repaired with three horizontally aligned 20 in. (508 mm) wide unidirectional carbon fiber sheets using different commercially available epoxies. Twenty years later, the carbon fiber-reinforced polymer concrete masonry unit (CFRP-CMU) bond was determined through selective pulloff tests that were preceded by detailed nondestructive evaluation. Results showed that despite superficial damage to the top epoxy coating and debonding along masonry joints, the residual CFRP-CMU bond for the wall surface was largely unaffected by prolonged exposure to Florida’s harsh environment. Therein, over 90% of the failures were in the concrete substrate. Although bond was poorer at mortar joints because the CFRP was well bonded to the masonry surface, its impact on structural performance of the repair was expected to be minimal. Overall, the repairs proved to be durable with both epoxy systems performing well.