Electrical Curing of Concrete:

This method is not used in India. It is more costly. It is mostly used in extremely cold climatic regions. Passing alternating current of low voltage could cure concrete products and high amperage through electrodes in the form of plates covering the entire area of two opposite faces of concrete. The potential difference generally adopted is between 30 and 60 V. Evaporation is prevented by using an impermeable rubber membrane on the top surface of the concrete. Firstly up to 3 hours, the resistance of concrete to flow of current decreases due to rise in temperature. There is increment in resistance afterwards, due to decrease in the quantity of free water available in the concrete due to hydration and evaporation. This period of rise in temperature should be about 12 hours. The duration of electrical-curing should be about 48 hours at the temperature of 50°C or 36 hours at the temperature of 70°C. The concrete products are cooled gradually in heat- insulated chambers for a minimum period of 24 hours. By electrical-curing concrete can attain the normal 28 days strength in a period of 3 days.