Self-Compacting Fibre Reinforced Concrete (SCFRC) is a rather useful material in precast industry, leading to a significant reduction in construction time and costs, and possibly even labour shortages. The addition of fibres enhances the behaviour of SCFRC structures at both serviceability limit state (durability, cracking, deformation) and ultimate limit state (bearing capacity and ductility), allowing in many cases to replace, totally or partially, the web reinforcement. However, even if several experiments available in literature showed that fibres, if provided in sufficient amount and with an adequate toughness, are significantly effective as shear reinforcement, just few of them focused on the shear behaviour of prestressed elements made of Self-Compacting Polypropylene Fibre Reinforced Concrete (SCPFRC). Polypropylene (PP) fibres are now able to provide significant toughness and ductility to concrete. In this context, the present paper focuses on the use of PP fibres as shear reinforcement in SCPFRC prestressed double tees. Experimental results of full-scale tests on six prestressed double tees made in Self-Compacting Concrete (SCC) and SCPFRC are presented. Firstly, shear tests were conducted in areas where the prestressing is uniformly distributed, in order to evaluate the possibility of replacing the minimum amount of shear reinforcement only by PP fibres. Moreover, several tests were also done at the end zones, which are more critical in shear as the beneficial effects of prestressing is not yet totally active (the prestressing force has still to be completely transferred from tendons to concrete). Experimental results show that PP fibres can be used both to totally substitute the shear reinforcement required in zone with uniform prestressing and to reduce the conventional reinforcement in the end zones of prestressed double tees.

Shear behaviour of prestressed double tees reinforced by polypropylene fibres

Conforti A.
;
Minelli F.;Plizzari G. A.;
2015-01-01

Abstract

Self-Compacting Fibre Reinforced Concrete (SCFRC) is a rather useful material in precast industry, leading to a significant reduction in construction time and costs, and possibly even labour shortages. The addition of fibres enhances the behaviour of SCFRC structures at both serviceability limit state (durability, cracking, deformation) and ultimate limit state (bearing capacity and ductility), allowing in many cases to replace, totally or partially, the web reinforcement. However, even if several experiments available in literature showed that fibres, if provided in sufficient amount and with an adequate toughness, are significantly effective as shear reinforcement, just few of them focused on the shear behaviour of prestressed elements made of Self-Compacting Polypropylene Fibre Reinforced Concrete (SCPFRC). Polypropylene (PP) fibres are now able to provide significant toughness and ductility to concrete. In this context, the present paper focuses on the use of PP fibres as shear reinforcement in SCPFRC prestressed double tees. Experimental results of full-scale tests on six prestressed double tees made in Self-Compacting Concrete (SCC) and SCPFRC are presented. Firstly, shear tests were conducted in areas where the prestressing is uniformly distributed, in order to evaluate the possibility of replacing the minimum amount of shear reinforcement only by PP fibres. Moreover, several tests were also done at the end zones, which are more critical in shear as the beneficial effects of prestressing is not yet totally active (the prestressing force has still to be completely transferred from tendons to concrete). Experimental results show that PP fibres can be used both to totally substitute the shear reinforcement required in zone with uniform prestressing and to reduce the conventional reinforcement in the end zones of prestressed double tees.
2015
978-0-88865-168-6
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11379/502455
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