In the aluminum alloy template for the first time in the process, often a metal aluminum and concrete chemical reaction, resulting in concrete surface floating ash and poor perception, the main reasons are as follows:

As the main element of aluminum alloy template, metal aluminum (Al) belongs to the active metal, acid and alkali will produce a chemical reaction. The concrete is mainly composed of hydroxides and silicates, for the composite of strong alkaline substances, when they first contact, it is inevitable to produce chemical reactions, and concrete coagulation generated by the high temperature to strengthen its reaction to produce carbon dioxide (CO2 ), Hydrogen (H2) and other gases and aluminum hydroxide (Al (OH) 3), calcium carbonate (CaCO3) and other substances, reflected in the concrete surface phenomenon: in the concrete surface 2mm level, there will be local bending of the gas marks (CO2, H2 floating path, the focus is reflected in the vertical surface of the wall, the floor is relatively smooth because the gas from the concrete surface evaporation) and floating ash (CaCO3), but because of the activity of aluminum metal, after 1 ~ 2 After the full reaction, the aluminum template itself will produce "passivation" to form a targeted oxide layer, play a natural isolation. Therefore, the aluminum alloy template construction will appear first 1 ~ 2 layer of concrete surface is poor, and 2 layers after the concrete surface will be improved phenomenon. And all types of template oil can only improve the surface quality of concrete, and can not be enough to prevent the first 1 ~ 2 layer of natural reaction.

 First layer reaction

More than two

Although there is a phenomenon described above, it should be noted that although the first 1 to 2 layers of the aluminum template do not meet the requirements of the F4 water template, it is still possible to meet the basic requirements of F2 and above (Hong Kong Standard Gradual irregularities permitted<10 2="" mm="" in="" m="" even="" surface="">

In view of the above phenomenon, almost all of the aluminum alloy template suppliers and construction enterprises, in order to improve the first 1 ~ 2 layer appearance, over the years carried out various attempts, but the effect is not very obvious. The main methods are as follows: pre-acidification (failure reasons: concrete composition is complex, and the concrete grades are different, it is difficult to prevent template reaction) in advance in the aluminum template and concrete contact surface paint (failure reasons: poor aluminum surface adhesion , The construction of the beating, collision, high temperature are likely to damage the paint surface, resulting in paint stripping paint on the concrete surface, the formation of secondary pollution, affecting the latter part of the surface maintenance)

As the surface of the first 1 ~ 2 layer 2mm or so feel bad, but also to meet the requirements of F2 and above, more will not affect the late decoration, aluminum alloy template as one of the basic characteristics of the above phenomenon has become a common phenomenon in the industry. With the widespread use of aluminum templates in Hong Kong, Macau and China, this phenomenon has been understood and accepted by the general contractor and Party A. In spite of this, He Di Technology is still on how to solve this phenomenon set up a special research topics, continue to develop new template oil and aluminum alloy template surface coating methods, methods, tested, He Di technology using advanced spraying process, The production of aluminum alloy template surface spraying, which has basically solved the first 1 ~ 2 layer of concrete surface floating ash and so on, and in the practical application has achieved good results, in the long run, this method is feasible, Is also worth promoting the use of the industry!