Statistical determination of fracture parameters of concrete with wide variation of water-cement ratio

Abstract

The size effect and boundary effect fracture models were used to determine the fracture parameters of quasi-brittle materials through geometrically similar and non-geometrically similar specimens. Combining the characteristics of size effect and boundary effect, the concept of relative size was proposed. The simplified calculation method for quantitatively determining the fictitious crack growth length of concrete specimens with wide variation range of water-cement ratio under peak load. Based on the fracture test results of actual concrete, the tensile strength and fracture toughness of concrete with different water-cement ratios can be determined simultaneously. Using the normal distribution function, fracture curves with upper and lower limits covering all test data was established. According to the fracture failure curve, the minimum theoretical size of concrete specimens with different water-cement ratios satisfying linear elastic fracture mechanic was obtained. Furthermore, an analytical formula was established to directly determine the fracture parameters of concrete with different water-cement ratios from the peak load, and based on the analytical formula, the peak state of a large size structure meeting linear elastic fracture mechanic was predicted • The fracture toughness and tensile strength of concrete with different water-cement ratios can be determined by the proposed model in this paper. • The simplified calculation method of fictitious crack expansion Δafic for concrete samples with different water-cement ratio by determining peak load was quantitatively studied. • The relationship between the peak load and the fracture parameters is established, and the prediction of the peak state of the large-size specimen met LEFM was realized.