This paper seeks to investigate the effects of specimen / member size on the development of shrinkage strains in the concrete. The research was conducted based on various published literature on the effects of size on the development and magnitude of shrinkage in the concrete and its recommendations were compared with several current shrinkage predictions models.
Five different shrinkage prediction models were used for comparison to determine how the effects of specimen / member size are accounted for by each individual model and the values that each model would generate were also discussed. For the purpose of this thesis, only Drying Shrinkage will be considered, compared and discussed herein with the AS3600-2001, ACI 209R-92, CEB-FIP Model Code 1990 and other mathematical models (GL2000 and Model B3, Gilbert’s Model).
It was found that size of the specimen affects the rate and magnitude of the shrinkage in the concrete at a given time and it is very difficult to isolate the differences among the different prediction models that were used for discussion. For a given time period prior to the concrete reaching equilibrium with the service environment (i.e. ultimate shrinkage), shrinkage was found to have a significantly larger magnitude as the specimen / member size decreases (i.e. smaller / thinner specimens exhibit larger shrinkage strains).