Manufacturing, Durability and BondBehavior of FRP Bars with Nanoclay


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Title: Manufacturing, Durability and BondBehavior of FRP Bars with Nanoclay

Author(s): P.V. Vijay, H.V.S. GangaRao, and V. Krishnaswamy

Publication: Special Publication

Volume: 230


Appears on pages(s): 77-98

Keywords: bond; durability; FRP; moisture; nanoclay; pullout;pultrusion; shear; tension

Date: 10/1/2005

This paper focuses on the behavior of Glass Fiber Reinforced Polymer (GFRP)bars manufactured with nanoclay. Benefits of nanoclay in the resin for manufacturingFRP composites include reduced moisture ingress, better fire resistance, and enhancedresin stiffness. Several molds were developed at CFC-WVU laboratory to produce glassFRP bars with smooth surface, and crescent shaped or circular lugs. Bars weremanufactured at room temperature by manual pultrusion process with varying fibervolume content and percentage of nanoclay. Vinyl ester resin exfoliated with nanoclaywas used to manufacture GFRP bars with a fiber volume fraction of 44.7% and tested fortensile, bond and shear strength.Bars manufactured in this research and tested in tension had typical ultimate stress of108.76 ksi (749.87 MPa) –133.43 ksi (919.96 MPa) and stiffness of 4.18 msi (28.8 GPa) -4.67 msi (32.2 GPa). Pullout tests conducted on a bar with crescent-shaped lugs andcircular lugs embedded in concrete provided a maximum bond stress value of 2385 psi(16.44 MPa) and 1762.77 psi (12.15 MPa), respectively. Bars with nanoclay showed8.3% less shear strength than those without nanoclay (24.10 ksi (166.16 MPa) vs. 26.27ksi (181.13 MPa)). Bars with nanoclay absorbed more moisture initially than barswithout nanoclay, and the moisture absorption decreased with time.