Water sorption isotherms and hysteresis of cement paste at moderately high temperature, up to 80 °C

The constitutive models of concrete often consider water desorption isotherms to be near-equilibrium and significantly affected by moderately high temperature, 40–80°C, typically through microstructural changes. However literature data suggest that adsorption, not desorption, is moderate temperatures do cause This work supports the latter theory, dynamic vapor sorption experiments on cement paste at 20–80°C. Samples were pre-conditioned 60% relative humidity 20°C, measured for several ranges testing rates. results, corroborated classical DFT simulations, indicate adsorption mostly unaffected whereas out-of-equilibrium due ink-bottle effect humidity, interlayer low humidity. Starting from second cycle, higher features a shift cavitation pressure overall smaller hysteresis. A conceptual model pore-specific temperature-dependent hysteresis proposed qualitatively explain results.