Concrete admixture is a chemical substance that is mixed in the process of mixing concrete and accounts for less than 5% of the cement mass, which can significantly improve the performance of concrete. The characteristics of concrete admixtures are that they have many varieties and small dosages, which have a greater impact on the performance of concrete.
They have the characteristics of low investment, quick results, and significant technical and economic benefits. With the continuous progress of science and technology, admixtures have been increasingly used, and admixtures have become the fifth important component of concrete in addition to the four basic components.
Admixtures have a certain effect on improving the anti-carbonization performance of concrete. There is a certain linear relationship between the carbonation depth and porosity of concrete; admixtures have a great influence on the frost resistance of concrete. Concrete with air-entraining water-reducing agent is anti-freezing The performance is better, but the early strength agent alone has no effect on improving the frost resistance of concrete.
The product quality of the admixture must be qualified, and should be tested before use, and a factory quality certificate and test report should be provided. The content of the certificate includes the name of the manufacturer, product name, product characteristics, main ingredients and content, scope of application, suitable dosage, usage and instructions, matters needing attention, homogeneity indicators, performance indicators of concrete with admixtures, packaging, quality, Storage conditions, factory date, expiration date, etc.
For different admixtures, the corresponding test items are different, generally including water reduction rate, slump, air content, bleeding rate, setting time, compressive strength, steel corrosion, relative durability indicators, etc. The client, client, project name, purpose, sample name, place of origin and manufacturer, date of receipt of the sample, and items required for testing in the content of the test report shall be filled out by the test client, and the rest shall be filled by the test personnel. Fill in according to the test results, sign and seal.
For admixtures that require certain technical treatment measures to be used, consideration should be given to meeting technical requirements first, and the relevant technical person in charge must sign and approve before use.