Strengthening concrete beams for shear using CFRP-materials: evaluation of different application methods

This paper presents different methods and tests for the application of carbon fibre reinforced plastic (CFRP) fabrics and tapes to concrete beams. The purpose of the tests were twofold; first to study the shear force capacity of the beams both before and after strengthening; and second, to examine three different ways of applying the fabrics. These were: two hand lay-up systems, one vacuum injection system and one pre-preg system. The total number of beams tested was eight. The test results proved that a very good strengthening effect in shear could be achieved by bonding fabrics to the face of concrete beams. However, a lot of energy was released at failure, which led to brittle failures. The tests also showed that the techniques which used hand lay-up were preferable as compared to other systems, even though the fibre weight fraction was considerably less. However, the vacuum injection system was the most environmentally friendly method.