Long term behaviour of self compacting fibre-reinforced concrete beams

Self-compacting fibre reinforced concrete extends the versatility of concrete as a construction material, by providing an effective method of overcoming its intrinsic brittleness, and by simplifying the activities necessary for the RC structures construction. The behaviour of this material has been studied by many researchers but the level of knowledge concerning its long term behaviour is still limited. This work describes the first results of an experimental campaign aimed at investigating and comparing the long term behaviour of self-compactingconcrete beams containing steel fibres as well as standard re-bars. In the first stage of the tests the beams were notched in the mid-span section and loaded in order to pre-crack the concrete up to an opening of 0.2 mm. In the second stage of the tests the long term behaviour of the beams was studied by monitoring the mid-span deflection and the crack opening for 200 days, during which the beams were loaded using a four point bending scheme. During this phase the beams were kept in climate controlled room. The results show that the steel fibres are able to reduce, respect to the conventional reinforcement, the crack opening also under long-term loading thus improving the durability and reducing the deformability.