Effect of Different Temperatures on Epoxy Adhesive Used in Near Surface Mounted FRP Bars Strengthened Concrete Masonry Unit under Direct Shear Test

Abstract

The use of fiber reinforced polymer (FRP) materials has become common for increasing the structural element capacity. Near Surface Mounted (NSM) technique has been widely used for strengthening purpose as an alternative to the FRP externally bonded (EB) technique. In comparison with the EB technique, NSM technique has many advantages such as providing better anchorage and protection from external damage. This advantages led to reducing the risk of debonding failure. The bond performance of NSM FRP is ex-tensively studied in the past studies without consideration the influence of direct exposure to the service temperature. This study is the first attempt to evaluate the bond behavior when the NSM FRP is subjected to tension force and temperature at the same time. The level of temperatures considered in this study were ser-vice temperatures [range from-18◦ C (0◦ F) to 49◦ C (120◦ F)] which is more representative of structural elements in the field. The key parameters investigated include (1) the type of fiber, including glass fiber reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP), (2) the level of temperature applied on concrete masonry unit (CMU), including ambient, freeze and hot condition. The specimens were strengthened and subjected to tension force simultaneously with applying temperature under single-lap direct shear. These specimens compared with specimens later tested after exposure to the cycles of heating and cooling temperature. The behavior of specimens was investigated in terms of ultimate pull-out force, and mode of failure. The results showed that the NSM technique exhibited excellent performance when subjected to cycles of heating and cooling prior to testing. The contribution of the NSM FRP bars to the shear strength of the CMU was affected so that high reduction of FRP-epoxy bond properties was exhibited when exposed to high service temperatures, while there was insignificant reduction when subjected to the ambient and freeze temperature.

Meeting Name

7th International Conference on Structural Engineering, Mechanics and Computation, 2019 (2019: Sep. 2-4, Cape Town, South Africa)

Department(s)

Civil, Architectural and Environmental Engineering

Keywords and Phrases

Adhesives; Carbon Fiber Reinforced Plastics; Composite Structures; Concrete Construction; Concrete Testing; Fibers; Heating; Polymer Concrete; Reduction; Reinforcement; Shear Flow; Shear Strength; Structural Design; Surface Testing, Carbon Fiber Reinforced Polymer; Concrete Masonry Units; Fiber Reinforced Polymers; Glass Fiber Reinforced Polymer; Heating and Cooling; Near Surface Mounted; Near Surface Mounted Frp Bars; Structural Elements, Fiber Reinforced Concrete

International Standard Book Number (ISBN)

978-113838696-9

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2019 CRC Press/Balkema, All rights reserved.

Publication Date

01 Sep 2019

Link to Full Text

Share

 
COinS