8.12 : コンクリートの養生

Concrete curing is accelerated by applying heat and adding moisture, yielding concrete with higher early strength.

Steam curing, often used for precast products, moves them on a conveyor through a chamber or covers them in plastic, allowing circulation of steam at atmospheric pressure.

The typical steam-curing cycle for concrete begins with an initial delay period of moist-curing, followed by a heating period, raising the steam temperature at a rate of 40 to 60 degrees Fahrenheit per hour until it reaches a maximum of 150 to 180 degrees Fahrenheit.

This peak temperature is maintained with no additional heat applied, and the concrete absorbs residual heat and moisture during this period.

The steam-curing cycle concludes with a cooling period, during which the temperature decreases.

The electric curing technique applies alternating current to heat the concrete member through external electrodes, the reinforcing steel within the concrete, or electric blankets, accelerating the curing process.

Alternatively, heating concrete using infrared heaters, circulating hot oil around the steel forms, or covering concrete exposed to cold temperatures with insulating blankets facilitates accelerated curing.