A fractional order rate approach for modeling concrete structures subjected to creep and fracture

The paper analyses the behaviour of concrete in the case of quasi-static fracture. The attention is focused on the interaction between strain-softening and time-dependent behaviour: a viscous rheological element (based on a fractional order rate law) is coupled with a micromechanical model for the fracture process zone. This approach makes it possible to include a whole range of dissipative mechanisms in a single rheological element. Creep fracture in mode I conditions is analysed through the finite element method and the cohesive (or fictitious) crack model. The comparison with creep tests executed on three-point bending conditions (three different load levels) shows a good agreement both in terms of failure-lifetime, and, load–displacement. [Copyright &y& Elsevier]