SIZE EFFECT TESTS OF HIGH-STRENGTH CONCRETE

Results of failure of cylinders under the uniaxial compression are rep orted. Cylinders of three different diameters (37.5, 75, and 150 mm) w ere tested For all the cylinders, the height to diameter ratio was h/d = 2. The cylinders were made of microconcrete with maximum aggregate size 4.76 mm and the compressive strength (f(c)') of concrete was foun d between 34 and 48 MPa depending on the size of specimens. The concre te mix proportions of water:cement:aggregate:silica fume:superplastici zer were 0.3:1:4:0.1:0.08. The results reveal the existence of a signi ficant size effect that can be approximately described by the size eff ect law previously proposed by Bazant. The experiments indicate that l arger specimens tend to fail in a more brittle manner, while smaller s pecimens tend to fail in a less brittle or more plastic failure.