Study on Bond-Slip Behavior between Seawater Sea-Sand Concrete and Carbon Fiber-Reinforced Polymer (CFRP) Bars with Different Surface Shapes

Abstract

The application of CFRP bar and seawater sea-sand concrete (SSSC) in construction can overcome the shortcomings in conventional reinforced concrete, such as corrosion induced by carbonation and chloride ingress. In this study, the bond-slip behavior between an SSSC cube and CFRP bar has been investigated, and different CFRP bar surface shapes have been considered. A total of 27 specimens (9 groups) were fabricated for a pull-out test, where three types of CFRP bar with different surface shapes were used: smooth regular bars, double-wrapped bars and ribbed bars. Bond strength, bond-slip curve, and failure mode have been presented and discussed. FE models have been constructed and validated by experimental results. The effect of concrete compressive strength and relative area of ribs on bond strength has been studied through numerical simulations. It is found that the bond strength increased with concrete compressive strength, and the ribbed bar had significantly higher bond strength than the smooth regular bar. Pull-out failure was observed when the cover-depth-to-bar-diameter ratio was no less than 4 and, otherwise, splitting failure occurred. In addition, a simple formula has been proposed to approximately evaluate the bond strength between an SSSC cube and CFRP bar and validated by experimental results, and analytical expressions for different bond-slip curves have also been developed.

Bond performance between hybrid fiber-reinforced concrete and BFRP bars under freeze-thaw cycle

“…With the development of FRP materials, FRP bars became more common in the construction industry, which made it crucial to predict the bond-slip process between FRP bars and concrete. Several bond-slip constitutive models of FRP bars with high recognition were developed as a result of continuous research by scholars [ 45 ]. Comparing the fitted bond-slip curve results from various models allowed us to assess the applicability of each bond-slip constitutive model in this experimental study.…”

Experimental Studies and Application of Fiber-Reinforced Polymers (FRPs) in Civil Infrastructure Systems: A State-of-the-Art Review

“…The bond behavior between concrete and FRP bars was investigated to prevent mode failure. For example, Gao et al [ 61 ] analyzed the bond–slip behavior between seawater sea sand concrete and CFRP bars with different surface shapes using a pull-off test. The results indicated that the ribbed bar has a significantly higher bond strength than the regular bar.…”

Numerical Analysis of an Innovative Double-Strap Joint for the Splicing of Near-Surface Mounted Fiber-Reinforced Polymer Bars for Reinforced Concrete Beam Strengthening

“…It has been limited primarily to the investigation of anchoring length; that is, the bond effect [21,22]. This, among other things, is also concerned with numerical testing [23][24][25][26]. Recommendations for required anchoring lengths in cases of the classical way of cut-off splicing via longitudinal overlapping (as for steel reinforcement) relate to manufacturer's data for specific materials, shapes, and surface treatments of the additional FRP reinforcement [20], and relate to limited classic lap splice research recommendations [27][28][29].…”