Abstract
This study aims to examine the potential use of a geopolymeric matrix as a sustainable alternative to commercial mortars in carbon fabric-reinforced matrix composites. Single-lap shear tests were conducted to examine the bond behavior at the fabric-matrix interface. Test parameters included the type of matrix (geopolymeric and cementitious matrices) and the bonded length (50 to 300 mm). The geopolymeric matrix was a blend of fly ash/ground granulated blast furnace slag activated by an alkaline solution of sodium silicate and sodium hydroxide. The bond behavior of the geopolymeric-matrix specimens was characterized and compared to that of similar specimens with a cementitious matrix. The specimens failed due to fabric slippage/debonding at the fabric-matrix interface or fabric rupture. The effective bond lengths of the geopolymeric- and cementitious-matrix specimens were 150 and 170 mm, respectively. The geopolymeric-matrix specimens exhibited higher fabric strains, higher ultimate loads, and a steeper strain profile along the bonded length than those of their cementitious-matrix counterparts. New bond-slip models that characterize the bond behavior at the fabric-matrix interface for geopolymeric- and cementitious-matrix specimens were developed. Both models exhibited equal maximum shear stress of 1.2 MPa. The geopolymeric-matrix model had, however, higher fracture energy and higher slip at maximum shear stress than those of the cementitious matrix model.
Highlights
Fabric-reinforced cementitious matrix (FRCM) composite-based systems have been widely used in flexural strengthening, shear strengthening, column confinement, seismic retrofitting of beam-column connections, and masonry-infilled reinforced concrete frames [1,2,3]
The maximum loads of the geopolymeric-matrix specimens, except GM-250, were on avaverage 71% higher than those of their cementitious-matrix counterparts
The higher loads exhibited by the geopolymeric-matrix specimens implies better bond at the fabric-matrix exhibited by the geopolymeric-matrix specimens implies better bond at the fabric-matrix interface
Summary
Fabric-reinforced cementitious matrix (FRCM) composite-based systems have been widely used in flexural strengthening, shear strengthening, column confinement, seismic retrofitting of beam-column connections, and masonry-infilled reinforced concrete frames [1,2,3]. In addition to their non-corrosive nature, FRCM systems involve the use of cement-based mortars as a matrix rather than epoxy. This results in an enhancement in the bond at the matrix-substrate interface and improvement in the fire resistance of the composite system relative to those of epoxy-based composite systems [1,2,3]. Changing the properties of the fabric surface by sizing or coating can enhance the chemical bond and friction at the fabric-matrix interface and mitigate telescopic failure, thereby allowing full utilization of fabric tensile properties and improving the performance of FRCM composite systems [4,5,6,7,8]
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