Abstract:
Three-point bending (TPB) beams with small span-depth ratios were utilized to research the fracture properties of concrete. An approach for determining the fracture parameters of TPB beams with small span-depth ratios was provided, which was based on linear interpolation between the calculation formulas of TPB beams with the span-depth ratios of 2.5 and 4. The experimental results of TPB specimens with three small span-depth ratios and the available results in the literature were used to verify the present formulae. The results indicate that when the specimen depth was increased from 100 mm to 200 mm, the obtained initial fracture toughness remained constant, while the unstable fracture toughness increased gradually but the growth was small. The obtained double-
K fracture parameters by the presented method were in good agreement with the results determined by the method proposed in the literature. The initial fracture toughness obtained by the analysis method agreed well with those obtained by the experimental method. The applicability of the presented method to TPB beams with small span-depth ratios was further verified by the experimental data in the literature.