Performance of RC beams retrofitted with CARDIFRC® after thermal cycling

Title: Performance of RC beams retrofitted with CARDIFRC® after thermal cycling
Author(s): F. Farhat, B.L. Karihaloo
Paper category : conference
Book title: International RILEM Symposium on Concrete Science and Engineering: A Tribute to Arnon Bentur
Editor(s): J. Weiss, K. Kovler, J. Marchand, and S. Mindess
Print-ISBN: None
e-ISBN: 2912143926
Publisher: RILEM Publications SARL
Publication year: 2004
Nb references: 18
Language: English

Abstract: A new retrofitting technique using CARDIFRC ®, a material compatible with concrete, has recently been developed at Cardiff University. It overcomes some of the problems associated with the current techniques based on externally bonded steel plates and FRP (fibre-reinforced polymer), which are due to the mismatch of their tensile strength and stiffness with that of concrete structure being retrofitted. This study investigates the effect of thermal cycles on the performance of reinforced concrete control and retrofitted beams. The concrete beams were heated to a maximum temperature of 90?C from the room temperature of about 25?C. The number of thermal cycles varied from 0 to 90 cycles. After the requisite number of thermal cycles, the beams were tested at room temperature in four-point bending. To determine the effect of thermal cycles on the performance of the concrete beams 48 beams were prepared. Of these beams, 32 were retrofitted with CARDIFRC ® and 16 left as control. Two types of reinforced concrete beams have been investigated in this study: beams without shear reinforcement, which were designed to fail in flexure or in shear, and beams with sufficient shear reinforcement designed to fail in flexure. The test beams were pre-cracked at 75 percent of the ultimate strength of the control beams. Two retrofit configurations were explored to improve the behaviour of the beams: flexural and shear strengthening (beams retrofitted with one strip bonded on the tension face only and beams retrofitted with one strip on the tension face and two strips on the sides). The tests indicate that the retrofitted beams are stronger, stiffer and more importantly failed in flexure. It was also observed that thermal exposure does not cause any degradation in the retrofitted beam strength. CARDIFRC ® is therefore a very promising material for repair and retrofit in high temperature environments.

Online publication: 2004-03-25
Classification: Applications
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143926.080