The purpose of conservation is to create appropriate conditions of temperature and humidity to ensure or accelerate the normal hardening of concrete. Different curing methods have different effects on concrete performance. Commonly used conservation methods include natural conservation, steam curing, dry and wet heat curing, autoclaved curing, electric heating curing, infrared curing and solar energy conservation. The time of maintenance experience is called the maintenance cycle. For comparison purposes, test specimens that specify the performance of concrete must be cured under standard conditions. The standard maintenance conditions adopted in China are:
The level I level control temperature is 20±2°C, the level II level control temperature is 20±5°C, the standard curing time is 28 days, and the humidity is not less than 95%. Suzhou concrete
Concrete curing includes natural conservation and steam curing.
During concrete curing, it is important to strengthen the humidity and temperature control of the concrete, minimize the exposure time of the surface concrete, and timely cover the exposed surface of the concrete (covering with tarpaulin, plastic cloth, etc.) to prevent evaporation of surface moisture. Before the concrete of the exposed surface protective layer is first set, the covering should be rolled up, and the surface should be rolled at least twice with a trowel to make it flat and covered again. At this time, it should be noted that the covering should not directly contact the concrete surface until the concrete is finally set.
The steam curing of concrete can be divided into four stages: static stop, warming, constant temperature and cooling. The steam curing of concrete should meet the following requirements:
(1) During the static stop period, the ambient temperature should be kept below 5 °C, and the end of the filling should be 4-6 hours and the concrete can be heated after the final condensation.
(2) The heating rate should not be greater than 10 °C / h.
(3) During the constant temperature period, the internal temperature of the concrete should not exceed 60 °C, and the maximum temperature should not exceed 65 °C. The constant temperature curing time should be determined according to the requirements of the demoulding strength of the component, the concrete mix ratio and the environmental conditions.
(4) The cooling rate should not be greater than 10 °C / h. Concrete manufacturer