Transport properties in cracked fibre reinforced concrete

TORRIJOS, M. C.; ZERBINO, R.; GIACCIO, G.

Guimaraes

Simposio; 8th RILEM International Symposium on Fibre Reinforced Concrete; 2012

RILEM

The incorporation of fibres gives concrete the ability to control the process of initiation and propagation of cracks, resulting in a high performance material with improved mechanical properties, particularly residual capacity and toughness; is important to highlight that these benefits translate in a greater durability of the constructions. However, there is limited information on the effect of fibres on the permeability and porosity although both play a decisive role in the long term durability. In addition, there are few works that explore the contribution of the fibres in the durability of concrete after the initiation of the damaged processes. In this work the relationship between the crack pattern and the transport properties in fibre reinforced concrete is analyzed. Beams of 150x150x600 mm were moulded with steel fibre reinforced concrete and cut in 60 mm height slices. In each beam two slices were cut perpendicular to the filling direction and six slices were cut parallel to the filling direction. The fibre orientation number was assesed in each slice. Then, the slices were precracked by the splitting tensile test to induce cracks of width ranging between 0.01 and 0.60 mm. As transport properties the capillary absorption and water permeability were evaluated in each slice. It was found a clear influence of the orientation of fibres on post peak splitting behaviour. The transport properties were affected in different way according to the cracks width. Permeability was affected by cracks wider than 0.10 mm meanwhile capillary absorption changed in presence of very thin cracks and remained not affected by cracks wider than 0.10 mm. 1