Early-age creep deformation of a high strength self-compacting concrete

The age of loading and the stress level are important parameters in the precast/prestress industry as they are related to the time of each production cycle, as well as to the concrete deformation. For this reason, a study about the influence of the age of loading and the stress level on the deformation of a self-compacting concrete with a mix composition typically used in the prefabrication of prestressed bridge girders was performed. This concrete develops 60 MPa within 24 h. Its deformation was evaluated at the stress-to-strength ratio of 30% for six stages of loading at the ages of 12, 16, 20, 24, 48 and 72 h. At the age of 12 and 24 h, deformation was also evaluated at the stress-to-strength ratios of 20% and 40%. Loaded specimens were kept under constant stress during at least 600 days in a climatic chamber with a temperature and a relative humidity of 20 °C and 50%, respectively. Deformation in non-loaded specimens was also measured to determine shrinkage and calculate creep deformation. Results are compared with the predictions provided by the Eurocode 2.