Glass fiber reinforced polymer (GFRP) composite is applied widely in continuously reinforced concrete pavement (CRCP) because of its prominent advantages in properties and cost compared with conventional steel materials. This paper investigated influences of concrete strength, embedded depth, surface form, and diameter of bars on the GFRP-concrete bond performance by a series of pull-out tests. A finite element model was built to simulate the whole pull-out process. The test results showed that, within a certain range, rib depth has a positive effect on both slip control and stress improvement. Smaller rib spacing had a positive effect on controlling the slip displacement, but the diameter of bars and concrete strength had a negligible impact on both the bond strength and slip displacement. The developed finite element model (FEM) could provide similar results as the pull-out tests, and the model also demonstrated a distinct peak value in a shear stress cloud chart. Meanwhile, in order to analyze the effect of embedded depth on bond strength, a normal distribution model was utilized to fit the shear stress distribution. The analysis results retrieved from the normal distribution model, with an extreme small relative error less than 4 %, were more in line with the experimental results than the traditional average distribution model.

Corrosion-resistant, electromagnetic transparent and lightweight fiber-reinforced polymers (FRPs) are accepted as valid alternatives to steel in concrete reinforcement. Reinforced Concrete with FRP Bars: Mechanics and Design, a technical guide based on the authors more than 30 years of collective experience, provides principles, algorithms, and pr

fib Bulletin 40 deals mainly with the use of FRP bars as internal reinforcement for concrete structures. The background of the main physical and mechanical properties of FRP reinforcing bars is presented, with special emphasis on durability aspects. For each of the typical ultimate and serviceability limit states, the basic mechanical model is given, followed by different design models according to existing codes or design guidelines. Composite FRP materials are still relatively new in construction and most engineers are unfamiliar with their properties and characteristics. The second chapter of this bulletin therefore aims to provide practising engineers with the necessary background knowledge in this field, and also presents typical products currently available in the international market. The third chapter deals with the issue of durability and identifies the parameters that can lead to deterioration, which is necessary information when addressing design issues. A series of parameters is used to identify the allowable stress in the FRP after exposure for a specified period of time in a specific environment. The bulletin covers the issues of Ultimate Limit States (primarily dealing with flexural design), Serviceability Limit States (dealing with deflections and cracking), Shear and Punching Shear and Bond and Tension Stiffening. It provides not only the state-of-the-art but also in many cases ideas for the next generation of design guidelines. The final chapter deals with the fundamental issue of design philosophy. The use of these new materials as concrete reinforcement has forced researchers to re-think many of the fundamental principles used until now in RC design. The bulletin ends with a discussion of a possible new framework for developing partial safety factors to ensure specific safety levels that will be flexible enough to cope with new materials.

"In 1993, the CEB Commission 2 Material and Behavior Modelling established the Task Group 2.5 Bond Models. It's terms of reference were ... to write a state-of-art report concerning bond of reinforcement in concrete and later recommend how the knowledge could be applied in practice (Model Code like text proposal)... {This work} covers the first part ... the state-of-art report."--Pref.