Strength, strain capacity, and modulus of elasticity were determined for eighty large prism specimens with enlarged ends, 45 x 45 cm in cross section and 360 cm long, and eighty 10 x 10 x 55 cm small prism specimens. The relationships between the tensile properties of full-mix mass concrete with 150 mm maximum size aggregate (MSA) and that of the same concrete wet screened to 40 mm MSA and tested in small specimens were obtained. The relationships of tensile properties of the same concrete tested in large and small specimens also were studied.