Assessing sampling interval-dependent roughness in fractured steel fiber reinforced concrete using a double-exponential decay model

Abstract

This study introduces a double-exponential decay (DED) model to investigate the sampling interval (δ)-dependent behavior of crack morphology roughness in steel fiber reinforced concrete (SFRC). The root mean square (Z2-3D) of the directional derivatives in 3D digital morphology is employed to quantify the roughness and its anisotropic behavior. Surface morphologies of 24 fractured specimens are captured by using a laser scanner and the obtained results are re-meshed based on the Point-Kriging algorithm. The roughness is represented by the ratio of surface area to projected area (RS) and Z2-3D values along different directions at various δs (4–3000 μm). The outcomes suggest that the values of RS and Z2-3D both decline, but the anisotropy of surface roughness is enhanced at an increased δ. The DED model is able to properly reflect the decay behavior in which the morphology roughness is classified into three corrugated components based on their distinct attenuation laws. A satisfactory agreement with the literature data is observed, validating the presented methodology. The reported findings in this work are useful for enhancing the understanding of the formation of crack morphology roughness and its relationship to the damage process of SFRC.