Failure lifetime of concrete structures under creep and fracture

The paper summarises research about the behaviour of concrete in the case of quasi-static fracture and presents some new results about size effects on failure lifetime. The interaction between strain-softening and time-dependent behaviour is examined by means of a viscous rheological element (based on a fractional order rate law) coupled with a micromechanical model for the fracture process zone. Creep fracture in mode I conditions is analysed through the finite-element method and the cohesive crack model. Creep tests executed on three-point bending conditions (at different load levels) are investigated to assess the influence of specimen size on failure lifetime