In the last years, size effects involved in cracking of concrete structures have been regarded at two levels: - at the level of the material to determine intrinsic constitutive relations for the cracking of concrete, - at the level of…
In the last years, size effects involved in cracking of concrete structures have been regarded at two levels: - at the level of the material to determine intrinsic constitutive relations for the cracking of concrete, - at the level of the structure to account for size effect in design LU'-'"'""-''UU and in finite element analysis. Based on some experimental results obtained in uniaxial tension, paper discusses the physical origins of size effects in concrete cracking, and the consequences on the design of concrete structures. 2 Experimental on the mechanical size effects in concrete It is beyond scope this paper to make an exhaustive review literature concerning experimental data on the mechanical scale m concrete. Just some results are presented which allow to explain the physical origins of this scale effect. These data are taken from the series of uniaxial tension tests carried out by Rossi et al. (1994a). Two series of test were performed on: - in the first study, three diameters of cylindrical specimens of slenderness ratio 2 were 89, 1l3, 160 mm. One type of concrete was studied whith a aggregate size of 0 = 12 mm, and a compressive strength of fc = 48 Approximatively 50 tensile tests per specimen diameter were the second three diameters of cylindrical specimens of slenderness 2 were tested: 30, 60, 150 mm. Three types of u,., ................ ,""" with a compressive strength respectively to diameter of the maximum aggregate size was same for concretes: 20 mm.