Assessment of Methods of Predicting Time-Dependent Deformations of Plain and Reinforced Concrete

Predicted creep and shrinkage of plain and reinforced concrete have been compared with experimental values over a period of 8 months; the comparison included symmetrical and
unsymmetrical arrangements of reinforcement. Although total (creep + shrinkage) deformations can be estimated fairly accurately, creep of plain concrete and shrinkage of reinforced concrete are overestimated by the established methods of prediction. Analysis of the various proposed reduction factors for deformation of reinforced concrete suggests that the role of creep of plain concrete in influencing the modular ratio is different for accurate predictions of creep and shrinkage. In the case of creep of reinforced concrete, creep of plain concrete is not important, but in the case of shrinkage of reinforced concrete it appears that tensile creep, and not compressive creep, of plain concrete could be of importance.

J.J. Brooks, A.E. Gamble and M.M. Chouman