Precautions for application of concrete admixtures

In experiments and practices, people have found that adding admixtures to concrete can improve the technical functions of concrete and obtain significant technical economic effects. However, accurate and reasonable use has a major impact on the technical and economic effects of concrete admixtures. If used improperly, accidents may occur. Therefore, when using admixtures, you should pay attention to the following points:

(1) Selection of types of concrete admixtures

There are many types of admixtures with different effects, especially for different types of cement. When selecting admixtures, it should be determined through experiments based on project requirements, on-site material conditions, reference to relevant data, and experiments.

(2) Determination of the dosage of admixtures

Concrete admixtures are all suitable for mixing If the dosage is too small, it usually cannot achieve the expected effect; if the dosage is too large, it will constitute waste, sometimes affecting the quality of concrete, and even causing a quality accident. Therefore, the best dosage should be determined through experiments.

(3) Method of adding admixtures

Admixtures are mixed into concrete The methods in things are different, and their functions are also different. For example, the post-mixing method of water-reducing agent is better than the first-mixing method and the simultaneous-mixing method, and the dosage is only half of that of the first-mixing method and the simultaneous-mixing method. The so-called first-mixing method is to mix the water-reducing agent with the cement first and then mix it with the aggregate and water; the simultaneous-mixing method is to dissolve the water-reducing agent in water to form a solution and then add it to the mixture and mix it together; the post-mixing method It means that after the concrete mixture is delivered to the pouring location, the water-reducing agent is added and mixed evenly again for pouring. Therefore, the use of concrete admixtures must be determined through experiments based on project characteristics, material conditions and construction conditions.

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