Mixed-mode fracture analysis in high-performance concrete using a Brazilian disc test

Abstract

This paper reports and discusses the results of an experimental investigation into the fracture mechanical properties of high-performance concrete (HPC) with a compressive strength higher than 100 MPa. In total, 6 specimens for a three-point bending test and 12 specimens of a Brazilian disc under a mixed-mode load were included in the experimental measurements. The fracture toughness was evaluated for mode I in the case of a three-point bend test and a Brazilian disc test, allowing a correlation between two geometrically different specimens. The fracture resistance under mixed mode I/II was analysed using the Brazilian disc test specimen with a central notch. To evaluate the fracture resistance under the mixed mode a generalised maximum tangential stress criterion was employed and the value of the critical distance rC is discussed as an appropriate HPC material characteristic. The last objective of this study was to provide some experimental data that can be useful in engineering practice for calibrating numerical constitutive models.Avtorji poro~ajo in razpravljajo o eksperimentalnih raziskavah lomno-mehanskih lastnosti visokokakovostnega betona (HPC; angl.: High Performance Concrete) s tla~no trdnostjo nad 100 MPa. V kompletu so izvedli trito~kovne upogibne preizkuse na {estih (6) vzorcih in na dvanajstih (12) vzorcih v obliki diskov so izvedli brazilski preizkus, ki predstavlja me{ano (natezno/tla~no) obremenitev. Dolo~ili so lomno`ilavost za na~in I v obeh primerih; to je trito~kovnega upogibnega preizkusa in brazilskega testa, upo{tevajo~geometrijske lastnosti obeh vrst vzorcev. Odpornost proti lomu v me{anem na~inu I/II so analizirali s pomo~jo brazilskega preizkusa na vzorcih (diskih) s centralno zarezo. Da bi ovrednotili odpornost proti lomu v me{anem na~inu, so uporabili posplo{eni kriterij maksimalne tangencialne napetosti in ocenili, da je vrednost kriti~ne razdalje primeren kriterij za oceno lastnosti HPC. V zadnjem delu te {tudije so podali nekaj eksperimentalnih podatkov, ki bi lahko bili uporabni v in`enirski praksi za kalibracijo numeri~nih konstitutivnih modelov.

Influence of chlorides on the fracture toughness and fracture resistance under the mixed mode I/II of high-performance concrete

“…Another reason is that the calculation and evaluation is relatively simple as the inputs are values of the SIFs, T-stress, fracture toughness KIC and critical distance rC, which are determined from the analytical formulas. In addition to this, it provides reliable results on the concrete material, see [65][66][67][68].…”

A Comparison of the Fracture Behaviour of Various Concrete Grades under Mixed Mode I/II Loading

“…A polycarboxylate based superplasticizer was selected based on its compatibility with cement. The concrete was mixed in a volume of 0.7 m 3 and poured immediately into moulds [16].…”

“…Table 2: Overview of the fracture mechanical properties of C 50/60 [15] and HSC [16] The Brazilian disc specimens have an initial notch length 2a = 40 mm, a radius R = 75 mm and a thickness B = 30 mm. This gives a relative crack length a/R = 0.267.…”

On the localisation of the FPZ under a pure mode II load identified by a hybrid method

“…The mixture was mixed in small volume batches of 0.7 m 3 and poured directly into the moulds. The material composition is equal to that used in previous work [43,48]. The mixture's composition per m 3 is shown in Table 1.…”