Monitoring of Epoxy-Grouted Bonding Strength Development between an Anchored Steel Bar and Concrete Using PZT-Enabled Active Sensing

Abstract

Anchored steel bars have been widely used in retrofitting of existing concrete structures. The bonding strength between the anchored steel bar and the concrete is critical to the integrity of the strengthened concrete structure. This paper presents a method to monitor epoxy-grouted bonding strength development by using a piezoceramic-enabled active sensing technique. One concrete beam with an anchored steel bar was involved in the monitoring test, and two concrete beams with six anchored steel bars were used in the pull-out test. To enable the active sensing, a Lead Zirconate Titanate (PZT) patch was bonded to the surface of the exposed end, and piezoceramic smart aggregates were embedded in each concrete specimen. During the monitoring experiment, signals from PZT sensors and smart aggregates were acquired at intervals of 0, 20, 40, 60, 80, and 100 min. In addition, a pull-out test was performed on each of the remaining six anchored steel bars in the two concrete beams, while the signal was recorded in the test. Furthermore, a wavelet packet analysis was applied to analyze the received signal energies to investigate the bonding strength development between the concrete and the anchored steel bar during the epoxy solidification process. The test results demonstrate the effectiveness of the proposed method in monitoring the bonding strength development between the anchored steel bar and the concrete, using the PZT-enabled active sensing.

Detecting Debonding between Steel Beam and Reinforcing CFRP Plate Using Active Sensing with Removable PZT-Based Transducers

“…Because of the piezoelectricity effect, a PZT patch can be used as either a sensor or an actuator [51], and a PZT patch can generate and detect stress waves [34,42,52]. Traditionally, a PZT patch can be embedded inside a structure or bonded to a structural surface to conveniently enable the active sensing approach [53][54][55].…”

Old - New Concrete Interfacial Bond Slip Monitoring in Anchored Rebar Reinforced Concrete Structure Using PZT Enabled Active Sensing

“…Moreover, the PZT-enabled active sensing approach was introduced by Jiang et al (2019) to demonstrate the development of bonding strength along the interface layer between the concrete and the bonded rebar. The AE parameters including the amplitude, duration, and signal strength were employed to characterize the stage of concrete bond deterioration (Abouhussien and Hassan, 2017b).…”

Detecting of the Crack and Leakage in the Joint of Precast Concrete Segmental Bridge Using Piezoceramic Based Smart Aggregate

“…In practical engineering, the commonly used methods for detecting the cracks in the concrete include image-based methods [ 26 , 27 , 28 ], radar-based methods [ 29 , 30 ], ultrasonic [ 31 , 32 , 33 ], and impact echo (IE) [ 34 , 35 ], among others. In recent years, studies show that the lead zirconate titanate (PZT) has been applied in SHM [ 36 , 37 ] due to its superiorities of low cost, strong piezoelectric effect [ 38 , 39 ], sensing and actuation [ 40 , 41 ], wide bandwidth [ 42 , 43 ] and energy harvesting [ 44 , 45 ]. Using active sensing methods, PZTs have been successfully applied in monitoring concrete bending stiffness [ 46 ], detecting the grouting quality in prestressed tendon duct [ 47 ], inspecting the loosened connection [ 48 ] and characterizing cracks [ 49 , 50 ].…”