Conventional Models for Shrinkage of Concrete
Models for shrinkage in cement concrete are generally used to express volume changes in concrete without external loads. Shrinkage models which are calibrated for ordinary normal strength concrete with Portland cements are presented and compared. They were developed using many years’ theoretical and experimental research works which tried to follow the development of concrete technology and allow for better estimation of this phenomenon. Estimation of shrinkage strains according to ACI 209, B3, Eurocode 2 models is outlined. For practical application the latest model (Eurocode 2) is adjusted for initial parameters available at the design stage. Comparison of development over time and final values of shrinkage strain for different models indicate that the calculated results may differ significantly. Correct calculation of shrinkage strains in concrete structures sensitive to time-dependent deformations is still very difficult and sometimes requires individually calibrated models. Due to advances in concrete mixes and types of cements, newly developed models usually estimate higher values of final shrinkage in ordinary concrete than the previously used models. Adoption of proper magnitude of shrinkage strains in concrete structures is necessary for their durability and economic design.
Shrinkage of Concrete, Shrinkage Models, Time Dependent Properties
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