Bond Strength Between Cast-in-Place Ultra-High-Performance – Concrete and Glass Fibre Reinforced Polymer Plates Using Epoxy Bonded Coarse Silica Sand

ABSTRACT: A significant amount of attention has been directed toward the use of fibre reinforced polymer (FRP) materials in structural applications, par­ticularly as main components in hybrid structural members. As a result, the need for an effective connection mechanism that can maintain full composite action at the interface between adjacent dissimilar materials is critical in order to achieve optimum performance of the hybrid structural members. The objective of this experimental program was to investigate the bond perform­ance between glass fibre reinforced polymer (GFRP) plates and cast-in-place Ultra-High-Performance – Concrete (UHPC) using epoxy bonded coarse silica sand aggregates at the bond interface. Both shear and tension tests were conducted using three different types of epoxy adhesives. The general effec­tiveness of the connection mechanism at the bond interface as well as the relative performance of each epoxy adhesive used were investigated. Analy­sis showed that, of the three epoxy adhesives tested, the specimens bonded at the interface between the UHPC and GFRP plates using the moisture tol­erant epoxy adhesive intended for bonding of hardened concrete and steel performed the best.

KEYWORDS: fibre reinforced polymers, glass, Ultra-High-Performance – Concrete, bond, epoxy, silica sand, shear, tension

Introduction

The potential uses of fibre reinforced polymers (FRPs) for structural applica­tions have been explored in great detail since early 1970s [1]. More recently, research has focused on investigations relating to hybrid FRP structural mem­bers, which incorporate a combination of different FRP materials, conventional materials as well as other high performance materials, such as Ultra-High-Per­formance – Concrete, in specially designed cross sections in order to optimize the most advantageous qualities of each distinct material [2-5]. In order to achieve the best performance in these hybrid structural members, full compos­ite action is required across the complete cross section. This has led to numer­ous investigations with the aim at determining and predicting the behaviour of different types of connection methods at various material interfaces [6-13].

The main objective of this particular research was directed towards the study of a particular type of connection mechanism used at the interface between glass FRP (GFRP) plates and cast-in-place UHPC. The connection mechanism used consisted of coarse silica sand aggregates bonded to the GFRP plate using an ep­oxy adhesive, similar to previous research performed in regards to bonding between GFRP and normal strength concrete [13]. Experimental testing and anal­ysis were performed to evaluate the shear and tension strength at the GFRP – UHPC interface using this particular type of connection mechanism. Additionally, comparisons between the effectiveness of the connection mechanism using three different types of epoxy adhesives for aggregate bonding were made.

Materials