What is the main impact of retarder on the performance of concrete?

1. Retarder is a common water-reducing agent used to increase the initial setting time of concrete. At the construction site in summer, proper addition of retarder can make the new Mixed soil maintains good ductility over a long period of time.

2. The retarder is a surfactant that only has a mathematical adsorption and refinement effect in the concrete, but does not directly participate in the hydration reaction and transformation of the concrete. It forms new organic matter, so it has no direct impact on the final strength of the concrete within the required dosage range. However, because it delays the initial setting time of the concrete, it affects the initial strength of the concrete to a certain extent. Only the final strength is normal. Can catch up with or exceed the concrete without retarder.

In today’s rapid development of concrete, retarder plays a very critical role. As everyone’s understanding of retarder continues to increase, the use of retarder will become more and more common, especially when making large-volume concrete where it is necessary to reduce the hydration heat of concrete rising time and delay the hydration valley of concrete. Agents are essential.

Slow down the initial setting and final setting time of concrete without affecting the final strength of concrete. It can be used independently or in combination with admixtures, etc., and has certain water-reducing effects. Generally, it does not affect the quality of concrete. When used together with admixtures, it can increase the water reduction rate. If over-admixed, the concrete will not set for a long time, thus damaging the quality of the concrete. Pay attention to this during the renovation project. Current test evidence confirms that generally retarder has an impact on the initial setting time of concrete, and there is no test data for other properties.

There are various retarders, such as sodium gluconate, white sugar, sodium citrate, etc. According to the requirements of different construction sites, different retardants are used in admixtures. The retarder affects the initial setting time of concrete but does not affect the strength of concrete. The retarding time of some underwater concrete works can even reach about 60 hours. At this time, ordinary retarder cannot exceed this requirement. Following overseas successful experience, Zouping County Delin New Material Technology Co., Ltd. has launched a variety of retardant modifiers coated with diversified inorganic phosphonic acid (salts) and polyhydroxy citrates, which can effectively solve these problems and product mud resistance, The slump retention properties are better than those of common modifiers.

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