The Influence of Short Fibre Additions on the Pullout Behaviour of Reinforced Concrete

One of the principal factors affecting the bond between reinforcement and concrete is the anchorage length of the rebar embedded in the concrete. Requirements for minimum anchorage lengths prescribed in design codes can lead... [ view full abstract ]

One of the principal factors affecting the bond between reinforcement and concrete is the anchorage length of the rebar embedded in the concrete. Requirements for minimum anchorage lengths prescribed in design codes can lead to congestion in the reinforcement and complications in detailing.
Adding short fibres to concrete has been shown to control the formation of tensile micro-cracks in concrete, which can increase the peak bond stress between the concrete and the reinforcement. One common test for measuring the bond between the materials is the pullout test.
This paper compares the pullout behaviour of ribbed rebar reinforced with steel, polypropylene and glass short fibres respectively. Results are compared to previously published values and show the potential for using short fibres to reduce the required anchorage length of main reinforcement by up to 10 - 15%.