Restraint stress due to autogenous shrinkage and drying shrinkage in high-strength concrete

Autogenous shrinkage and drying shrinkage, as well as the resulting restraining stress and cracking, of high-strength concrete were investigated. Free shrinkage and internally restrained shrinkage tests were performed in which the sealing periods and the age of drying commence were changed. The later was the beginning of the drying, the smaller was the total shrinkage. The autogenous shrinkage strain, determined using the shrinkage strains of specimens sealed at different ages, was lower than the value of seal-cured specimens. As a result of restraining tests using D25 restraining bars, no cracking occurred in specimens in which only autogenous shrinkage was induced. On the other hand, cracking occurred in nearly all specimens air-dried from 1,3, and 7 days.