Impact of temperature on the demoulding of concrete elements with a polarization process

A recent study proposed a new process for demoulding concrete elements based on the principle of electro-osmosis, consisting of applying an electric potential between the reinforcement and formwork which causes the water displacement towards the concrete/formwork interface where a film of water is formed avoiding the adhesion of the concrete on the formwork. The quality of facing and demoulding has been shown to be dependent on the polarization parameters (voltage value, time and duration of its application) and therefore optimal parameters were assessed. However these parameters were found in a very limited condition of temperature, only at 20 ± 2 °C. In this new study we consider the parameters optimization scheme in other room temperature conditions. In this respect an experimental device was developed in order to quantify the amount of displaced water at (20 ± 2 °C) and (8 ± 2 °C) according to the voltage value and duration of its application. We showed that, under the same polarization conditions, the quantity of water transported decreases with decreasing room temperature. This decreasing of water quantity caused the alteration of demoulding and facing quality. To overcome this issue, the optimal polarization conditions have been revisited in order to take into account the temperature. When transposed in situ, our method performed successfully at 20 ± 2 °C and at 8 ± 2 °C as well and it could be a better choice than the previous demoulding methods like those using vegetable oils, developed recently to replace mineral oils, they cannot be used at low temperatures.