Contribution of mixture design to chemical and autogenous shrinkage of concrete at early ages

In this work, autogenous shrinkage at early ages (<24 h) was accurately measured by linear displacements on slabs simulating field constructions. The best correlation of the amount of chemical to autogenous shrinkage was found at the time of 4 h after the final setting time. It was possible to account for test arrangement artifacts, such as thermal dilation, to get a measure of pure autogenous shrinkage. Many material parameters, such as superplasticizer (SP) and aggregate amount, effected the magnitude of autogenous shrinkage in secondary ways. These consequential effects, such as amount of bleed water and time of setting, were accounted for in the slab measurements. Recommendations are given for reducing the likelihood of cracking due to early age chemical and autogenous shrinkage.