Creep model of high-strength concrete containing supplementary cementitious materials

Long-term creep prediction of high-strength concrete (HSC) has been a significant issue in the design of concrete structures. To achieve high performance, supplementary cementitious materials (SCMs) are mixed into HSC. However, few creep models have been developed to estimate the creep of concrete that contains SCMs, and there are no design codes available which can calculate the creep of HSC containing SCMs. This paper systematically investigates the creep behavior of HSC that contents SCMs. Two comprehensive databases were established, one of which is used for evaluating the elastic modulus and the other for assessing the creep. Comparison between the databases data and the existing formulas have been conducted. Further, ACI committee 318-84 formula and GL 2000 formula are collected for the prediction of elastic modulus and a modified creep model considering the influences of SCMs content and concrete strength have been proposed. The parameters in the modified creep model are assessed using a computational intelligence method called particle swarm optimization (PSO). Finally, a comparison between the modified creep model and the current widely used code models are performed using several statistical indicators. The results show that the modified creep model exhibits better precision compared with the existing widely used code creep models, and the modified creep model can be used for the prediction of the creep strain of HSC that contains SCMs.