Four-point bending tests for the fracture properties of concrete

Abstract

This paper evaluates the fracture properties of concrete using four-point bending test which the beam segment near the midspan crack section is under pure bending. Five different initial crack-depth ratios varying from 0.2 to 0.6 for concrete specimens were explored. The corresponding values of load, crack mouth opening displacement and midspan deflection were simultaneously recorded. The fundamental fracture parameters of critical effective crack extension length, critical effective fracture toughness and fracture energy were analyzed. More specifically, two approaches named pure bending approach and FPB approach were introduced to determine the critical effective fracture toughness. The results indicate that four-point bending test can be utilized to study the fracture properties of concrete.