Evaluation of Three-Point Bending Fracture Tests of Selected Concrete: Mechanical Fracture Parameters

In this paper, authors focus attention on mechanical fracture parameters obtained from records of three-point bending fracture tests on concrete specimens with initial notch. Total eight sets of specimens were tested. Three specimens at the age of 28 days were tested in each set. Concrete was different in dosage of Portland cement CEM I 42.5 R and amount of used superplasticizer. The Effective Crack Model (ECM) was used to evaluate the load vs deflection diagrams to obtain modulus of elasticity and effective fracture toughness; specific fracture energy was determined using work-of-fracture method. Modulus of elasticity, tensile strength and fracture energy were also subject of identification via inverse analysis based on artificial neural network, which aim is to transfer the input data obtained from the fracture test to the desired material parameters.