Effect of Corrosion on Mechanical Properties of RC Beams Using Ultrasonic Guided Waves

Abstract

Reinforced concrete (RC) structures have been used in construction since ancient times in major and minor infrastructure, such as bridges, dams and buildings. However, RC structures face deterioration due to several problems such as ageing, disastrous damage due to earthquakes and environmental effects. These factors affect the condition and performance of RC structures. Consequently, assessment of damage deterioration in concrete structures is in great demand and is vital to maintain the structure both for safety and economic considerations. Cracking of concrete due to corrosion of reinforcement is one of critical problems in reinforced concrete (RC) structures. Here, an application of ultrasonic guided waves to corrosion monitoring is studied. The initial part of the report highlights Structural Health Monitoring and Ultrasonic Monitoring methods which are slowly being used in the realm of Civil Infrastructure. It is demonstrated that the onset of corrosion and nucleation of cracking are readily identified by Ultrasonic monitoring. Guided ultrasonic waves offer a potentiall y attractive solution . In the present stud y, bars embedded in concrete are subje cted to corrosion. These specimens are monitored ultrasonically using longitudinal guided waves specific core seeking and surface seeking modes are used for detection of a particular t ype of damage due to corrosion. For this purpose, we conduct the Pulse Transmission Investigations. The reinforcements h ave been excited at one end with an ultrasonic pulse using piezoelectr ic transducer which acts as the transmitter and on the othe end piezoelectric transducer which acts as r eceiver. It is observed that corrosion of reinforcing bars in concrete is discernible using ultrasonic guided waves. Further the effect of corrosion on load carr ying capacity of RC beams is investigated. Parameters of modulus of rupture, maximum deflection and percent mass loss are determined. A correlation is established between ultrasonic voltage and static parameters of modulus of rupture and mass loss to predict the level of deterioration due to corrosion using ultrasonic guided waves.