ABSTRACT

Manipulation with concrete prefabricate usually takes place soon after the concreting. Concrete mixtures for the production of concrete prefabricated elements shall, in addition to requirements for the resulting concrete strength, also meet the requirements for concrete handling strength. The required handling strength of the concrete shall normally be achieved at 18 hours after concreting. Concrete compressive strength, tensile strength and modulus of elasticity at the time of 18 hours, 42 hours, 66 hours, 14 days, and 28 days, were measured during the experiment. Furthermore, the shrinkage of the concrete was measured over time of 1 day, 3 days, 7 days, 36 days, 68 days, and 91 days in 4 blocks of 75 mm, 125 mm, 150 mm, and 200 mm thickness.