Mode I fracture toughness of the thermally pretreated red Verona marble by means of the two-parameter model

The paper aims to analyse the effects of pretreatment thermal cycles on both mechanicaland fracture parameters of the red Verona marble, which is a natural stone of sedimentaryformation. The effects of the thermal pretreatment, consisting of freeze/thaw cyclesand simulating the atmospheric ageing on the material, are evaluated in terms of changesof the aforementioned parameters. Note that a wide variety of both specimen types andmethods to determine mode I plain strain fracture toughness of rocks are available in theliterature. The two-parameter model originally proposed for plain concrete is hereinadopted. Such a method, based on the experimental data obtained from three-pointbending tests on single edge-notched specimens, is able to take into account the slownonlinear crack growth occurring before the peak load, typical of quasibrittle materials,and presents the advantages of easy specimens preparation and simple test configuration.