EFFECTS OF SIZE AND CURING ON CYLINDER COMPRESSIVE STRENGTH OF NORMALAND HIGH-STRENGTH CONCRETES

The influence of cylinder size and curing on measured compressive stre ngth was investigated for different strength concretes. Three batches of ready-mix concrete with target compressive strengths of 35, 90, and 120 MPa (5000, 13,000, and 17,500 psi) were used. The curing conditio ns included air-cured, sealed, and water-cured for the 100-, 150-, and 200-mm- (4-, 6-, and 8-in.)-diameter cylinders. The beneficial effect s of preventing moisture loss and water-curing are directly observed i n the test results. The increased apparent strengths with decreasing c ylinder size are also presented. Relationships for compressive strengt h gain are given for normal strength, high-strength, and very high-str ength concretes studied, and for different curing conditions and diffe rent cylinder sizes.