Early-age contraction of concrete may cause excessive cracking in restrained concrete structures within the first few days after casting. Hie magnitude and rate of development of early-age deformation of Australian concrete is often not known reliably and restraint to shrinkage is often poorly modelled in structural design. In order to accurately quantify the early-age deformational characteristics of concrete, including shrinkage and tensile creep, a comprehensive experimental program is being conducted at the Centre for Infrastructure Engineering and Safety at UNSW. Dog bone-shaped specimens were tested in portable creep rigs specially designed to test the specimens in direct tension. The specimens were loaded at the ages of 1, 2, 3, 5 and 7 days in order to measure the tensile creep coefficients at different loading ages. Shrinkage was also measured on accompanying specimens. The tests were performed under constant sustained tension. Autogenous shrinkage was measured on dog bone specimens. Compressive creep was also investigated for the same concrete mix. Comparisons of the creep coefficient versus time curves for tensile and compressive creep at different loading ages are presented in this paper. Tensile creep was found to be significantly larger than compressive creep for the same loading level.
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