The effect of size in concrete compressive failure

Existing codes, including fib MC2010, usually express concrete failure criteria in terms of strength or yield criteria only. For tensile strength related failure modes, the dependence of the nominal strength on the size of the structure is well established and accounted in the codes. However, even though the failure of concrete under unconfined compression is of brittle type, no specific provision accounts for similar effects in compression. In this paper a wide experimental campaign on the effect of size of concrete in compression is presented. Cylindrical specimens of plane concrete with geometrical slenderness ratio ranging from 1:2 to 1:8 and for different diameters (10, 20, 40 and 80 cm) were considered. Experimental test results are presented and compared to existing scaling laws.