Crack Extension Resistance - Curve Study in Fracture of UHPC

Abstract

In this study, we conducted a comprehensive investigation into the 𝐾𝑅-curve of Ultra-High Performance Concrete (UHPC) by manipulating key parameters, namely initial fracture toughness, tensile strength, fracture energy, and Young's modulus. Through coding the empirical formula proposed by Wu et al. [2], we performed superimposition of P-CMOD curves to obtain the Kr-curve for UHPC. This analysis aimed to shed light on the behavior of UHPC under varying parameter conditions, providing valuable insights into its fracture properties. The goal of this study is to create an analytical technique for calculating UHPC's 𝐾𝑅-curve. The 𝐾𝑅-curve of concrete is analytically calculated based on the presumption that crack propagation begins after the difference in stress intensity factor induced by external forces and by the cohesive stress within the FPZ equals the initial cracking toughness. The size effect of the 𝐾𝑅-curve are not determine as in experiments we have only one size of beams available to perform test and UHPC material is very expensive as well. The impact of the cohesive stress crack opening displacement curve on the 𝐾𝑅-curve are explored after the validity of the approach is confirmed by experimental findings.