Flexural toughness characterization of steel, polymer and glass fibre reinforced concrete based on the notched beam test
  Sujatha Jose, Ravindra Gettu and Shabari Indhuja
  In the present work, the flexural behavior of concrete with different kinds of fibres have been characterized by center point loading (CPL) notched beam testing according to the EN 14651:2005 (E) and RILEM TC 162-TDF methods. The load-crack mouth opening (CMOD) and load-deflection curves were used to determine various toughness parameters, viz., flexural strength, residual flexural strength and equivalent flexural strength. A good correlation was found to exist between equivalent (feq) and residual flexural tensile strength (fR,j) parameters for steel and polypropylene fibre reinforced concretes. It was observed that hooked-ended steel fibres are more efficient in retaining the post-crack load-carrying capacity in comparison with polypropylene and glass fibres for the same volume fraction (0.4% Vf). The present study shows that the relationship between CMOD and midpoint deflection (δ) is almost the same for steel and macro polypropylene FRC at different dosages and, therefore, can be used to calculate CMOD or deflection when only one of them is known. The classification of FRC using the fib Model Code is also illustrated, which enables the designers to choose and specify FRC, based on its performance rather than by a type of fibre.