Justification and refinements of model B3 for concrete creep and shrinkage 1. statistics and sensitivity

Model B3 for creep and shrinkage prediction in the design of concrete structures, presented as a RILEM Recommendation in Mater Struct. 28 (1995) 357-365, is calibrated by a computerized data bank comprising practically all the relevant test data obtained in various laboratories throughout the world. The coefficients of variation of deviations of the model from the data are distinctly smaller than for the latest CEB model, and much smaller than for the previous ACI model (which was developed in the mid-1960's). The effect of concrete composition and design strength on the model parameters is identified as the main source of error. The model is simpler than the previous models (BP and BP-KX) developed at Northwestern University, yet it has comparable accuracy and is more rational.