Dependence of flexural behaviour of fibre reinforced mortar on material fracture resistance and beam size

Abstract

The flexural load-deflection curves for mortar reinforced with various fibre types (steel and synthetic) and various fibre volume fractions are measured using three different beam sizes. Three new flexural toughness indexes that reflect the general shape of the load-deflection curve are defined and calculated. The flexural strength/tensile strength ration [function of (italic small f)][function of (italic small f)]/[function of (italic small f)]'t is proposed as a parameter that reflects material brittleness -- a lower value for a more brittle material. Good correlations between two of the new flexural toughness indexes and parameters that involve only ff ft and the fibre length are found. These results indicate the possibility of getting a good idea of the flexural load-deflection curve by measuring only ff and ft in the laboratory. By realizing the dependence of structural behaviour on material fracture resistance, and also the ability of the parameters ff and ft to characterize this dependence, it is possible to develop simple formulae that directly express this dependence.