Review of the splitting-test standards from a fracture mechanics point of view

This paper analyzes by means of fracture mechanics the current splitting-test standards for concrete. The cohesive crack model, which has shown its utility in modeling the fracture of concrete and other cementitious materials, has been used to assess the effect of the specimen size, the specimen shape and the width of the load-bearing strips on the conventional splitting tensile strength, fst. The results show that, within the ranges recommended in the standards, the values of the splitting tensile strength can differ by up to 40%, and, consequently, fst can hardly be assumed to be a material property. Empirical formulae for concretes with different compressive strength (10–80 MPa) and maximum aggregate size (8–32 mm) have been used to show that fst is nearly specimen independent only for certain compositions, such as high-strength concretes, or when the aggregate size is under 16 mm. New closed-form expressions for fst are given in this paper to incorporate the effect of material properties, and some recommendations are drawn to minimize the influence of the width of the load-bearing strips.