Prediction model of concrete drying shrinkage from short-term tests

To solve the problem of concrete cracking in super-long structures in construction stage, shrinkage tests of concrete incorporating fly ash and ground granulated blast furnace slag in natural environment were conducted. The experimental results were compared with calculated results estimated by national and overseas existing models. It was concluded that none of the shrinkage prediction models adequately reproduced the observed shrinkage behaviour of concrete made with fly ash and slag, and most models underestimated the actual drying shrinkage strains except for GL2000 model. Using short-term experimental data, a new prediction model containing the effect of fly ash and slag was established by calibrating and modifying the existing shrinkage models. The model was verified by the later tests and the results show that the updating procedure is effective and the predicted shrinkage strains from the proposed model agree well with the measured. Therefore the proposed model may provide reference to the engineering structure.