Creep model of high-performance concrete at different loading ages

The present experimental and analytical study conducted a 710-day creep experiment on high-performance concrete(HPC) with a loading period of 45-260 days. The effects of the loading period on the shrinkage, elastic modulus, and creep of HPC, as well as the deviation from the prediction results of the ordinary concrete model, were examined. The results show that admixtures delay the hydration and hardening process of HPC compared with ordinary concrete. The influence of the loading period on the creep of the aged HPC is mainly reflected in the first day of creep development. The creep of concrete declines with the loading age following a hyperbolic function, f(C)(tau), so a creep model based on f(C)(tau) is established and validated by the test results. Moreover, we take f(psi)(tau) to characterize the influence coefficient of the loading period for the creep coefficient. f(psi)(tau) is first proposed based on the literature on the experiments with ordinary concrete with a loading age in the range of 1-5000 days and then modified based on the experimental results to predict the creep of HPC. Finally, the broad applicability of f(psi)(tau) was confirmed by applying it to six studies. The present study can provide a basis for establishing the creep model for high-performance concrete.