Application of concrete release agent

Fair faced concrete is one of the topics of the development of reinforced concrete construction technology. It is a comprehensive construction technology from design to construction quality, concrete mix design, finished product protection, concrete surface repair and formwork design. At present, there is no accurate definition and clear quality standard for fair faced concrete in the current national code, so there are different understandings and quality standards for fair faced concrete. The fair faced concrete emphasized by general construction units usually means that no plastering will be done after the formwork is removed, the concrete surface is flat and uniform in color, without honeycomb, pitted surface, exposed reinforcement, slag inclusion, pulverization, rust spots and obvious bubbles, and the concrete surface texture and "natural color" are pursued.

Obviously, the surface quality of concrete is a direct reflection of the success of as cast finish concrete, and the quality of formwork and release agent is the key to affect the surface quality of concrete.

The resin type surface coating named as template paint can be used as a long-term release agent for wood mold, bamboo mold, steel mold and other molds. The paint is welcomed by the concrete products and construction industry on one side, which solves the problems such as the easy rust of the template storage, the easy pollution of the concrete surface, the difficulty of demoulding and formwork cleaning, etc. In this paper, the function, characteristics and application technology of the paint are summarized for the reference of people in the field of concrete engineering.

1、 Function and characteristics of formwork paint

1. Protect the formwork and extend its service life.

In the concrete construction project, most of the formworks are stacked in the open air. How to protect the formworks from rusting is a big problem in the concrete industry. The paint is very popular because of its excellent corrosion and rust resistance. On the other hand, due to the isolation function of the paint film, the formwork is free from the abrasion of concrete aggregate and the corrosion of cement hydrate, so as to extend the service life of the formwork.

2. Improve the surface quality of concrete to achieve the effect of "as cast concrete". The surface of the paint film is smooth, bright and full, and the enamel is naturally formed, which can make up for the surface defects of the formwork; at the same time, the paint film has low stripping adsorption, which is easy to demould and clean, and avoids the adhesion of the concrete. The surface of the concrete formed by the paint is smooth, the hand feel is fine, it is like marble, and it has luster, which greatly improves the appearance quality of the concrete, fully shows the "natural color" of the concrete, and achieves the effect of fair faced concrete.

3. It can be used as a long-term release agent. The paint has good adhesion (the bonding strength with steel is 9Mpa), wear resistance and alkali resistance, and can be used repeatedly. The thermal decomposition temperature of the film is about 350. C. It has good heat and alkali resistance (saturated calcium hydroxide 80). C soaking for 48h, the physical and chemical properties do not decline), so it is also suitable for the steam environment.