The relationship between double-K parameters of concrete based on fracture extreme theory

The theoretical relationship between the initial fracture toughness and unstable fracture toughness in the double-K model was established based on fracture extreme theory. Using this relationship, the initial fracture toughness and unstable fracture toughness can be ob- tained from each other without experimental measurement. The values of unstable fracture toughness of three-point bending concrete beams were calculated with the input of initial fracture toughness. The calculation was simplified by using the weight function method. The calculated results were compared with those obtained by the double-K method. It is shown that the results obtained from these two methods show a good agreement. Unstable fracture toughness is affected by tensile strength and specimen size whereas unaffected by the ratio of initial crack length to depth. In addition, the softening function was found to have a negligible influence on the calculated result by a theoretical relationship.

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Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2020).