Retarder for concrete is mainly used at high temperatures, because the concrete is made by pouring and smoothing, which requires a certain amount of time, and because of the high temperature environment, the initial use of concrete without retarder The setting time is advanced, and if the initial setting time of the concrete has passed and the concrete still needs to be confined, you will affect the strength of the concrete, so the retarder will increase the initial setting time of the concrete; The retarder, in turn, will reduce the initial setting time of the concrete. Because the working temperature is too low, the initial setting time of the concrete can become longer, leading to disadvantages such as frostbite in the concrete, or because the construction project requires The initial setting must be carried out in advance and a retardant should be added, such as underwater concrete pouring.
Retarder (Set Retarder) is a preservative that reduces the hydration rate and heat of hydration of concrete or lime paste and increases the initial setting time. The purpose of adding retarder is to increase the strength of concrete. The hydration hardening time enables the fresh concrete to maintain ductility for a period of time, thereby adjusting the initial setting time of the fresh concrete.
Retarder is a water-reducing agent that can increase the initial strength of concrete without significantly harming the final strength. The main function of adding retarder is to accelerate the hydration rate of concrete and promote the hydration of concrete. The transformation of initial strength; it not only has the effect of early strength, but also has the effect of reducing water and increasing the required amount of water.
Concrete retarder can delay the hydration reaction of concrete, thereby prolonging the initial setting time of concrete, allowing fresh concrete to maintain ductility for a period of time, facilitating pouring, and improving the speed of decoration projects. A water-reducing agent that will not have a negative impact on the final properties of concrete. It is used in concrete summer decoration projects and underwater concrete construction sites. According to the different ingredients, concrete retarder for concrete is divided into two types: organic concrete retarder and inorganic concrete retarder. At present, lignocellulose sulfur salt is a widely used retarder with large production and sales volume. In addition, molasses, hydroxycarboxylic acids and many carbonate retarders are also widely used. Therefore, the different types of retarder are combined to explain the retarding function principle of the retarder. The initial setting time can be up to 24 hours, which does not affect the rebound of concrete. In addition, the quantity is small and the price is very high.
Retarder can slow down the initial setting time of concrete. The initial setting time of concrete in high temperature environment depends on the reduction. In order to facilitate the decoration project, the initial setting time must be increased, so retarder is added. The conversely, the bottom temperature environment must promote the initial setting of the concrete, so a retardant is needed.
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