Nondestructive Evaluation of RC Structures Strengthened with FRP Laminates Containing Near-Surface Defects in the form of Delaminations

Abstract

Fiber reinforced polymer (FRP) composites are being utilized in a wide range of application areas in structural rehabilitations because these materials are less affected by corrosive environmental conditions and known to provide longer life with less maintenance. However, there are still some concerns about FRP strengthened reinforced concrete (RC) structures, such as the presence of near-surface defects. Currently limited data exists regarding this issue. The presence of near-surface defects in the form of delaminations between the fiber reinforced polymer (FRP) laminate and concrete substrate can significantly affect the structural integrity and stiffness of the structural section. These defects should be properly detected and accurately located to access if injection or replacement is warranted. The control and assessment of these defects still require improvements in detection techniques and standardization in these assessment methods. The latest advances in non-destructive evaluation (NDE) techniques including technologies in microwave, acousto-ultrasonic, impact-echo and thermography are providing promising results in detecting such defects and are discussed in further detail in this paper.

Mechanical properties of self-compacting concrete with recycled bead wires

“…Additionally, ultrasonic pulse velocity method which requires evaluating the travel time, over a measured path length of a pulse of ultrasonic waves is used in order to estimate the strength of concrete samples. In ultrasonic pulse velocity, test velocity is calculated as a path length over travel time (Kobaka & Katzer, 2011;Myers & Ekenel, 2007). The measurement of ultrasonic pulse velocity is applied for the 28 days and 90 days cured concrete and effect of the volume of steel fibers on Ultrasonic Pulse Velocity (UPV) for cube samples are given in Figure 10.…”

Nondestructive Evaluation of FRP‐Concrete Interface Bond due to Surface Defects

“…Several prior studies utilized NDE methods for assessing the concrete-FRP bond. NDE methods such as thermography, ultrasonic C-scan, acousto-ultrasonic, impact-echo, microwave, ground-penetrating radar, eddy current, and laser shearography were used to scan and image three precracked reinforced concrete (RC) beams with externally applied CFRP laminates [1]. Artificial delamination was made when the epoxy was freshly applied.…”

Aplicaciones de las técnicas no destructivas Pull-Off y ultrasonidos en el control de calidad del refuerzo con materiales compuestos en estructuras de concreto

“…Por su parte, Ekenel y Myers [13], y Helmerich, Milmann y Wöstmann [14] utilizaron esta técnica de inspección no destructiva para la evaluación de delaminaciones en varios materiales compuestos. Por lo tanto, el control del comportamiento de la unión entre materiales es fundamental para eliminar la incertidumbre de la eficiencia de los refuerzos con materiales compuestos [15]- [16].…”