Concrete early age basic creep: Experiments and test of rheological modelling approaches

Early age cracking of massive concrete structures highly depends on creep and especially basic and thermal tensile creep. Direct tensile test are difficult to perform and actually no consensus on phenomenon involve and on tensile creep compliance (with respect to compressive one) is available. This contribution compares creep compliance of a concrete mix which is representative of a French nuclear power plant. The obtained creep compliances are similar in tension and in compression. Since temperature evolution could be important in massive structures, temperature effects are also studied. A significant increase of creep strains is shown for an elevated temperature (60 °C) but also for a temperature variation (from 20 °C to 60 °C). Finally, this paper highlights the ability of rheological models to reproduce creep strains due to complex loading history (thermal and mechanical ones).

► For the used concrete mix, compressive and tensile basic creep strains are similar.
► Experimental measurements highlight the non negligible effect of temperature on creep.
► Three ageing Kelvin Voigt units allow to predict the basic creep strains for simple loading history.
► A supplementary dashpot is necessary for complex loadings.
► Temperature effect on basic creep can be reproduce by thermo activation of the rheological units.