Modified metakaolin-based permeation-resistant and crack-resistant agent for concrete

Abstract

The invention discloses a modified metakaolin-based permeation-resistant and crack-resistant agent for concrete. The modified metakaolin-based permeation-resistant and crack-resistant agent for concrete comprises: by mass, 10 to 75% of modified metakaolin, 5 to 40% of fine limestone powder, 4 to 40% of superfine coal ash, 1 to 20% of calcined hydrotalcite, 2 to 40% of fine quartz sand and 0.2 to 20% of solid silane powder. A preparation method of the modified metakaolin comprises the following steps of putting dry and washed kaolin into a bowl mill, carrying out grinding to obtain kaolin powder, carrying out calcination of the kaolin powder at a temperature of 500 to 1000 DEG C for 0.5 to 6.0 hours to obtain metakaolin, putting the metakaolin into a dispersion machine, adding an organic modifier of sulfamate or triethanolamine into the metakaolin, wherein a mass ratio of the metakaolin and the organic modifier is in a range of (5000: 1) to (100: 1), and carrying out dispersion to obtain the modified metakaolin having a contact angle of 50 to 100 degrees and a specific surface area of 8000 to 15000m<2> / kg. The modified metakaolin-based permeation-resistant and crack-resistant agent for concrete can be utilized as a concrete additive, improves strength of concrete at different ages, does not produce obvious influences on concrete work performances, obviously improves anti-chloride ion penetration capability of concrete, reduces total shrinkage of concrete and improves crack resistance of concrete.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a modified metakaolin-based concrete anti-seepage and crack-resistance agent. Background technique [0002] With the development of society and the advancement of science and technology, the application field of reinforced concrete has been expanding, and gradually extended to marine engineering and other harsh environments. Therefore, this has higher requirements for the ability of concrete to resist various erosions. Reinforced concrete often works under the environmental conditions rich in chloride and sulfate. After a long period of erosion, the corrosive media such as chloride and sulfate in the environment will enter the concrete, resulting in corrosion of the reinforcement or expansion of the concrete volume, and finally causing the corrosion of the reinforcement. failure of concrete structures. At the same time, whether it is ordinary concrete or h...

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Problems solved by technology

But on the other hand, when mixed with metakaolin alone, it will significantly reduce the performance of concrete, and even affect the normal construction.

In order to ensure the working performance of metakaolin concrete, some studies have directly mixed solid water reducing agents into metakaolin admixtures as composite admixtures. This type of pre-compound water reducing agent may have poor adaptability to cement. problems, and may interfere with the water reducing agent used in the construction process, so this method still has problems in the actual application process

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