Effects of temperature rise on load-strain-time behaviour of geogrids and simulations

Abstract

To evaluate the effects of ambient temperature history on the load-strain-time behaviour, a series of tensile tests were performed on three geogrid types. The applied loading and temperature (T) schemes included: (i) continuous monotonic loading (ML) at different constant values of T; (ii) sustained (creep) loading (SL) during otherwise ML at different constant values of T and (iii) SL during which T was incrementally increased during otherwise ML. With an increase in T, the rupture tensile strength (Vmax) and the elastic stiffness decreased while the creep strain increased. For the same ultimate T, the creep strain by scheme (iii) was significantly larger than the one by scheme (ii). The residual rupture tensile strength (Vres) observed in ML that followed SL was nearly the same as Vmax in continuous ML at the same T, showing that creep is not a degrading phenomenon reducing Vres. A non-linear three-component (NTC) model was modified to incorporate the temperature effects. By modelling the trend that Vmax and stiffness decrease with an increase of T as a negative ageing effect, the modified NTC model successfully simulated all the different trends of load-strain-time behaviour, including creep strains, observed along various load and temperature histories in the experiments.