The effect of specimen thickness on fracture behaviour of concrete

The effect of specimen thickness on the fracture behaviour of concrete was studied. Prisms with double-edge notches were subjected to uniaxial tensile loading. Complete stress-deformation curves of prisms with a fixed height and width, but of different thicknesses, were experimentally measured Based on the results, fracture parameters f(t) and G(f) of the fictitious crack model and KSIcs and CTODc of the two parameter fracture model were evaluated. Additionally, a quantitative roughness analysis was conducted for fracture surfaces to determine a surface roughness number R(s). This study showed that fracture toughness values decreased and the material response became more brittle as the thickness of prisms was increased. An explanation based on the length of the fracture process zone is proposed for the observed thickness effect on material fracture behaviour of concrete.