This book is very useful in giving insight to the moisture related durability issues in bonding between Fiber Reinforced Polymer (FRP) and concrete. The experimental study is divided into two parts. The first part includes test mechanical properties of the resin and the concrete under the influence of water. In the second part, single lap shear bond test was conducted to compare the ultimate bond strength, failure modes, fracture energy, bond stress-slip curves with and without water immersion at different exposure periods. Finally, using the experimental results, a simple unified bond stress-slip relation was proposed ignoring the immersion duration and resin type which could address both non-immersion and immersion case. The proposed model showed good agreement with the experimentally observed local bond stress-slip relations for normal/high strength bond specimens with and without water effect.

FRP (fiber reinforced polymer) retrofit systems for reinforced concrete (RC) structures have been widely used in the past 10 years, and numerous studies on its short-term debonding behavior have been conducted extensively. Nevertheless, long-term performance and durability issues regarding such debonding behavior still remain largely uncertain and unanswered. In this study, comprehensive experimental and analytical investigations of debonding in FRP bonded concrete systems under long-term environmental exposure, namely moisture, have been performed to develop mechanics-based predictive debonding failure models and related design tools for the prevention of debonding failures. The experimental approach involves an investigation of debonding under moisture ingress, moisture reversal, cyclic moisture conditioning, using the concept of fracture mechanics and meso-scale tri-layer fracture specimens. Prolonged exposure to moisture condition has been shown to result in significant degradation of the FRP/concrete bond strength, while an irreversible weakening in the bond strength has also been observed in the fracture specimens under moisture cyclic condition. A predictive model has been developed based on the experimental results of the fracture specimens under variable cyclic moisture conditions for service life prediction of the FRP-strengthened systems. To incorporate this quantification method and experimental data, finite element analysis and correlation study have been conducted for RC beams externally strengthened with FRP plate. The cohesive zone model for interfacial fracture has been implemented, for which the properties of the interface were obtained from the meso-scale fracture tests. Test on laboratory-scale FRP-strengthened RC beam specimens under continuous moisture conditions has demonstrated the applicability of the methodology. In addition, molecular dynamics simulation has been conducted to gain more fundamental understanding of interface fracture behavior in bi-layer material systems (i.e. crack initiation and propagation direction) and the effects of material and interface properties at atomistic scale. Finally, a recommendation has been made to the current design of RC beams strengthened with FRP to prevent premature failure due to long-term exposure to moisture.

Fibre-reinforced polymer (FRP) reinforcement has been used in construction as either internal or external reinforcement for concrete structures in the past decade. This book provides the latest research findings related to the development, design and application of FRP reinforcement in new construction and rehabilitation works. The topics include FRP properties and bond behaviour, externally bonded reinforcement for flexure, shear and confinement, FRP structural shapes, durability, member behaviour under sustained loads, fatigue loads and blast loads, prestressed FRP tendons, structural strengthening applications, case studies, and codes and standards. Contents: .: Volume 1: Keynote Papers; FRP Materials and Properties; Bond Behaviour; Externally Bonded Reinforcement for Flexure; Externally Bonded Reinforcement for Shear; Externally Bonded Reinforcement for Confinement; FRP Structural Shapes; Volume 2: Durability and Maintenance; Sustained and Fatigue Loads; Prestressed FRP Reinforcement and Tendons; Structural Strengthening; Applications in Masonry and Steel Structures; Field Applications and Case Studies; Codes and Standards. Readership: Upper level graduates, graduate students, academics and researchers in materials science and engineering; practising engineers and project managers

Strengthening reinforced concrete (RC) members using fiber reinforced polymer (FRP) composites through external bonding has emerged as a viable technique to retrofit/repair deteriorated infrastructure. The interface between the FRP and concrete plays a critical role in this technique. This chapter discusses the analytical and experimental methods used to examine the integrity and long-term durability of this interface. Interface stress models, including the commonly adopted two-parameter elastic foundation model and a novel three-parameter elastic foundation model (3PEF) are first presented, which can be used as general tools to analyze and evaluate the design of the FRP strengthening system. Then two interface fracture models – linear elastic fracture mechanics and cohesive zone model – are established to analyze the potential and full debonding process of the FRP–concrete interface. Under the synergistic effects of the service loads and environments species, the FRP–concrete interface experiences deterioration, which may reduce its long-term durability. A novel experimental method, environment-assisted subcritical debonding testing, is then introduced to evaluate this deteriorating process. The existing small cracks along the FRP–concrete interface can grow slowly even if the mechanical load is lower than the critical value. This slow-crack growth process is known as environment-assisted subcritical cracking. A series of subcritical cracking tests are conducted using a wedge-driven test setup t o gain the ability to accurately predict the long-term durability of the FRP–concrete interface.

Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges contains lectures and papers presented at the Ninth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2018), held in Melbourne, Australia, 9-13 July 2018. This volume consists of a book of extended abstracts and a USB card containing the full papers of 393 contributions presented at IABMAS 2018, including the T.Y. Lin Lecture, 10 Keynote Lectures, and 382 technical papers from 40 countries. The contributions presented at IABMAS 2018 deal with the state of the art as well as emerging concepts and innovative applications related to the main aspects of bridge maintenance, safety, risk, management and life-cycle performance. Major topics include: new design methods, bridge codes, heavy vehicle and load models, bridge management systems, prediction of future traffic models, service life prediction, residual service life, sustainability and life-cycle assessments, maintenance strategies, bridge diagnostics, health monitoring, non-destructive testing, field testing, safety and serviceability, assessment and evaluation, damage identification, deterioration modelling, repair and retrofitting strategies, bridge reliability, fatigue and corrosion, extreme loads, advanced experimental simulations, and advanced computer simulations, among others. This volume provides both an up-to-date overview of the field of bridge engineering and significant contributions to the process of more rational decision-making on bridge maintenance, safety, risk, management and life-cycle performance of bridges for the purpose of enhancing the welfare of society. The Editors hope that these Proceedings will serve as a valuable reference to all concerned with bridge structure and infrastructure systems, including students, researchers and engineers from all areas of bridge engineering.