A new retrofitting technique using CARDIFRCRTM, 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. The tests indicate that the retrofitted beams are stronger, stiffer and more importantly failed in flexure. No visual deterioration or bond degradation was observed after thermal cycling of the retrofitted beams (the bond between the repair material and the concrete substrate remained intact) attesting to the good thermal compatibility between the concrete and CARDIFRCRTM. Therefore, this type of retrofit material can be successfully used in hot climates. The study also evaluates the performance of normal and high strength concretes repaired with CARDIFRCRTM using the wedge splitting test (WST). The main factors that could affect the bond between the repair material and concrete such as the surface roughness and thermal cycling are also investigated. It is shown that surface roughness plays a significant role in the overall bonding system, and no visual deterioration is observed after thermal cycling. Two analytical/computational models for predicting the ultimate moment capacity and the complete load-deflection behaviour of the retrofitted beams were applied. Both models predict very well the ultimate moment capacity of the retrofitted beams.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:583467 |
| Date | January 2004 |
| Creators | Farhat, Farhat Agribi |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/55930/ |
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