Stepwise loading-unloading creep testing of fly ash concrete and its constitutive model

Stepwise loading-unloading creep testing of concrete with fly ash content of 35%, and 50% was conducted. The time course curve of stepwise creep in fly ash concrete was obtained. Analyses have revealed that it had decelerated creep, constant velocity, and accelerated creep properties. Based on rheological theory, a non-linear viscoelastic-plastic rheological model (MSSB-NVPB) was constructed, and its constitutive relations and creep equations were obtained. Combined with experimental data, the model parameters were determined. The results showed that this model can characterize the creep properties of the fly ash concrete fairly well.