Time-Dependent Mechanical Evolution of Fly Ash Concrete Based on Compressible Packing Model

The mechanical properties of components are important indicators for calculating their structural reliability, which changes dramatically over time under sustained loading effects. In this study, the time-dependent development of the compressive strength (CS) of fly ash concrete (FAC) under sustained loading was investigated by means of creep and postcreep axial compressive mechanical property tests. A strength development model was subsequently established for the FAC on the basis of the compressible packing model (CPM) by introducing the time influence factor and FA contribution factor. The results showed that the CS of the samples after creep increased with increasing sustained loading time. Second, the increase in the CS of the samples after creep was more obvious than that of the samples without sustained loading. For the case in which both cement hydration and the cement equivalent time variation were considered, the CPM could be used to effectively calculate the time-varying CS patterns of samples with and without sustained loading.