ABSTRACT
Abstract An improved and simplified prediction model for creep and shrinkage of concrete is presented. New simplified expressions for empirical parameters representing the influence of the composition and strength of concrete on its long term deformations are given. This simplification is achieved by using sensitivity analysis which helped to identify which empirical parameters are important and which are not. A new expression for additional creep due to drying is derived based on the hypothesis of stress-induced shrinkage. Expressions for the effect of constant elevated temperature on basic creep are developed by generalizing the basic creep expressions using the concept of activation energy. Comparative statistics of errors of the proposed model and the current ACI and CEB models are given. The statistics are formulated so as to minimize the bias due to selection of specimen ages, test durations and reading times made by the experimenter. The problem of improving the predictions by extrapolating short-time test data on creep and on shrinkage is discussed. Keywords : Creep, Concrete, Design codes, Errors, Prediction, RILEM, Shrinkage, Statistics.
