Elasto-viscoplastic behaviour of polyester polymer mortars under monotonic and cyclic compression

The present paper is focused on study of the plastic behaviour and strain rate sensitivity of cylindrical polymer mortar specimens in monotonic and cyclic compression tests. The experimental results indicate elasto-viscoplastic behaviour: the load-carrying capacity of the specimen increases significantly with strain rate while the elastic properties remain practically constant. Under cyclic loading and unloading the material may exhibit hysteresis (a phase lag), which leads to a progressive accumulation of deformation. In this case, despite the high scatter of the experimental results, the number of cycles until failure tends to be smaller for lower loading frequencies. Preliminary ideas for a phenomenological model able to describe such nonlinear elasto-viscoplastic behaviour are also presented.