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Mechanical and Durability Screening Test Methods for Cylindrical CFRP Prestressing Tendons

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Lees, JM 
Toumpanaki, E 
Barbezat, M 
Terrasi, GP 

Abstract

Concrete prestressed with carbon fibre reinforced polymer (CFRP) tendons beneficially utilises the strain capacity and durability characteristics of the CFRP material. However, changes to CFRP tendon material formulations or production processes present a challenge when building up a body of knowledge to inform the long-term behaviour of a prestressed concrete system. Initial qualification tests can help identify the potential for FRP tendons to meet long-term mechanical and durability requirements. Protocols that can be undertaken on commercially produced cylindrical FRP pultrusions are particularly advantageous since the constituent materials and manufacturing processes are representative of the actual product. Selected mechanical/durability characterisation approaches, and their suitability for adaptation for wet specimens with cylindrical geometries, were critically assessed. A series of qualification tests were then conducted on CFRP tendons with three different resin systems. Tendon samples were exposed to wet environments to evaluate the longer-term solution uptake and associated mechanical durability implications. While characterisation measures such as the glass transition temperature, optical imaging and moisture uptake provided comparative results, the correlation with mechanical properties obtained from uniaxial tension, double notch shear and torsion tests was unclear. Using a sub-set of the mechanical test protocols, a retrospective analysis of CFRP tendons extracted from a prestressed concrete lighting pole under sustained load for 16.5 years was also reported.

Description

Keywords

Composite materials, Test procedures, Durability, Stress

Journal Title

Journal of Composites for Construction

Conference Name

Journal ISSN

1090-0268
1943-5614

Volume Title

Publisher

American Society of Civil Engineers (ASCE)
Sponsorship
Swiss Federal Laboratories for Materials Testing and Research for Industry, Construction and Commerce (Empa) (unknown)
SACAC Ltd