The Theory of Critical Distances to perform the static assessment of 3D-printed concrete weakened by manufacturing defects and cracks

The Theory of Critical Distances groups together a number of approaches postulating that, in cracked/notched materials subjected to static loading, breakage takes place as soon as a critical length-dependent effective stress exceeds the material tensile strength. The characteristic length used by the Theory of Critical Distances is a material property that can directly be estimated from the ultimate tensile strength and the plane strain fracture toughness. In the present investigation, based on a large number of bespoke experimental results, it is demonstrated that the Theory of Critical Distances is successful also in quantifying the detrimental effect of cracks and manufacturing defects in 3D-printed concrete subjected to Mode I static loading.