A magnetic method for non destructive monitoring of fiber dispersion and orientation in Steel Fiber Reinforced Cementitious Composites – part 2: correlation to tensile fracture toughness

Successful application with advanced fiber reinforced cement based materials relies on reliable design prescriptions and design-oriented test methodologies for the identification of relevant material properties, together with consistent and effective quality control procedures. The ‘‘randomly uniform’’ dispersion of fibers within a structural element is a crucial issue to be tackled, which, if not achieved, may lead to the activation of unanticipated failure mechanisms, thus lowering the load bearing capacity and jeopardizing the structural performance. It is henceforth evident that non-destructive techniques for fiber dispersion monitoring need to be developed and calibrated, as it has been going on for at least the last lustrum, and their outcomes to be effectively correlated to the mechanical performance of the material. In this paper a non-destructive method based on the magnetic properties of the composite has been applied to monitor the fiber dispersion and orientation in HPFRCC slabs. The results have been correlated to the tensile behaviour, measured according to the newly conceived ‘‘Double Edge Wedge Splitting’’ technique. The work herein presented stands as a step towards the assessment of non-destructive methods for fiber dispersion monitoring and their inclusion into a sound quality control procedure in a design oriented perspective.