A small concrete batching plant has a direct impact on the quality of the work, as well as the profitability of that company. Consequently, the production of concrete must be up to standard and then significant resources are spent on the production of waste. During the cold winter months, the production of concrete is somewhat restricted. As a small concrete plant manufacturer, we would like to provide you with details of what basic requirements must be met in the backyard production of concrete in winter?
When the average daily outdoor temperature is stable below 5°C for 5 consecutive days, technical measures for winter construction should be taken for the construction of concrete batching plants. Concrete can set, harden and gain strength as a result of hydration of cement and water. The speed of hydration in certain humidity conditions depends mainly on the temperature, the higher the temperature, the faster the strength growth, and vice versa is slow. When the temperature drops below 0 ℃, hydration basically stops, the temperature then continues to drop to -2 ~ -4 ℃, the water in the concrete began to freeze, water freezing volume increased by 8% ~ 9%, in the concrete internal ice crystal stress, so that the strength of very low cement stone structure inside the micro-cracking, while weakening the bond between cement and gravel and reinforcement, thus reducing the strength of concrete later. After thawing, the strength of frozen concrete can continue to grow, but it can no longer reach the original design strength level.
Concrete winter construction methods for: concrete maintenance during the method of non-heating. The method includes: chemical admixture method, admixture for the early strength agent and antifreeze.
(1) winter concrete mixing should be given priority to the method of heating water, when the heating water still can not meet the requirements, then the aggregate heating, water and aggregate heating temperature should be determined according to the thermal power calculation, but shall not exceed the provisions.
(2) To prepare concrete for winter construction, priority should be given to silicate cement or ordinary silicate cement, the strength grade of which shall not be less than 42.5Mpa, the amount of cement per cubic metre of concrete shall not be less than 300kg, and the water-cement ratio shall not be greater than 0.6.
(3) Aggregates must be clean and must not contain frozen materials such as ice and snow.
(4) Hot water or steam should be used to rinse the mixer before mixing, and the mixing time should be extended by 50% compared to normal temperature, and the mixing and feeding order should be aggregate, hot water, then cement and admixture. Ensure that the temperature of the concrete out of the machine is not less than 15°C and the temperature into the mould is not less than 5°C.
(5) The transport of concrete should be as short as possible, and containers for transporting and pouring concrete should have insulation measures.
(6) Before placing concrete, remove snow, ice and dirt from the formwork and reinforcement, and the containers used for transporting and placing concrete should have insulation measures. The temperature of concrete during transportation and pouring should be in line with the requirements of the thermal calculation, and if it is not in line with the requirements, measures should be taken to adjust it.
(7) Strictly control the quality of commercial concrete, admixtures and the water-cement ratio of concrete; shorten the time of concrete to the construction site and other Hou, so that it can be poured as it arrives.
YCZG mind that you immediately cover the concrete with plastic film to keep it warm, and then lay a layer of cotton felt on top to keep it warm; delay the removal of the concrete side moulds, and wrap it with plastic film and cotton felt immediately after removal.