by 1、 With the development of building engineering in the world, building industrialization has become the main development direction.
To implement the scientific concept of development and realize the sustainable development of housing construction, it is also necessary to take the road of new industrialization and industrialization through technological innovation.
In recent years, the Ministry of construction has advocated to improve the new housing construction system, that is, to improve the industrialization level of housing construction.
Therefore, prefabrication of construction projects has become its main development direction and trend.
The promotion of prefabricated concrete housing construction conforms to the national development strategy of energy conservation and emission reduction, and simultaneous realization of building energy conservation and building industrialization.
Its advantages are high quality, factory production, standard operation and stable production environment; Fast construction, free from weather, clean and safe construction site; Save building formwork, reduce garbage, dust and noise; It is suitable for office buildings, residential buildings, factories and large supermarkets.
Prefabricated concrete buildings are usually designed by dividing the buildings into several standard units and adopting industrialized methods to produce and construct prefabricated components; Therefore, in architectural design, its regularity, modularization and standardization should be considered in advance to facilitate the reuse of prefabricated component molds; However, for the appearance of the building, we can not ignore its aesthetic and personalized needs.
For the appearance changes of prefabricated concrete buildings, generally, the structural geometry, unit combination changes and finishing materials will be adopted in the design to meet the architects’ requirements for architectural aesthetics; This paper will make a general introduction to the external finishing technology commonly used in precast concrete components.
2、 Types of external finishes of prefabricated concrete members: the prefabricated members, especially the external wall plate, have basic requirements for the finishes, which must meet the performance of waterproof, anti fouling, durability and beauty.
Ceramic tiles or natural stones are often used to match the prefabricated concrete members in the selection of finishing materials; However, through the development of production technology, such as the water washed stone surface technology and the rubber mold turning technology, the architectural appearance can have more choices.
2-1 porcelain face tiles: pre paste the selected ceramic tiles in the component mold, and reverse the molding once, as shown in Fig.
1.
Fig.
1.
Ceramic tile facing prefabricated external wall plate 2-2 natural stone: pre paste the selected stone in the component mold, and reverse the molding once, as shown in Fig.
2.
Fig.
2.
Stone facing prefabricated external wall plate 2-3 water wash stone facing: use the surface retarding technology to wash the cement on the concrete surface with high-pressure water, showing the practice of exposing the aggregate, As shown in Fig.
3.
Fig.
3.
Water wash exposed stone finish 2-4 terrazzo finish: a process of pouring concrete with selected aggregates on the surface of the mold, polishing the concrete surface with water grinding equipment after the components are removed from the mold, and presenting the profile of bone material, as shown in Fig.
4.
Fig.
4.
(1) using colored waste glass as coarse aggregate, (2) using colored pebbles as coarse aggregate 2-5 fair faced concrete finish: also known as decorative concrete, it is a direct display effect of the natural color of concrete and the surface of the mold, The concrete is cast in one time, presenting a natural and simple texture.
The commonly used molds include wood mold, steel mold and rubber mold.
(1) Steel formwork finish: pour concrete directly on the precision processed steel formwork, control various factors that may affect the color difference of the concrete surface in the process, and take off the film for molding at one time, as shown in Fig.
5.
Fig.
5.
Prefabricated external wall components with clear water formwork (2) rubber molding formwork finish: take some natural materials or artificial patterns as the male formwork, and use rubber materials to turn the female formwork, As shown in Fig.
6.
Fig.
6.
Rubber molding die facing 2-6 color cement: adding color materials or using color cement to the concrete to make the surface of concrete components appear color, as shown in Fig.
7.
Fig.
7.
Color external wall hanging plate 2-7 others: Nowadays, the technology is advanced, and many new building materials have appeared, such as artificial stone and crystallized glass plate, which have been used; In addition, it is also a choice to add coating finish and real stone paint to plain concrete.
Or, the combination of the above is adopted, as shown in Fig.
8.
Fig.
8.
Sample situation in the laboratory of building materials group in Finland.
III.
common external surface finishing process of prefabricated concrete components.
The characteristics of prefabricated concrete components with surface finishing materials are that the surface finishing materials are pre embedded in the mold and poured with concrete in reverse once; Depending on the exterior decoration materials, there will be different production methods; The following are the most common production procedures of porcelain face tiles and stone materials as follows: 3-1 prefabricated components of porcelain face tiles are used as prefabricated components of porcelain face tiles.
Different methods will be selected according to the size, cross-sectional shape, surface characteristics and quality difference characteristics of the brick surface.
The brief description is as follows: 3-1-1 manual pre pasting adhesive film construction method this construction method is not applicable to tiles with too large size, thick thickness and uneven surface; The method is to first make a plate mold according to the requirements of the drawing, and form a rectangular standard unit.
After the bricks are arranged into the mold by manual brick arrangement, the foamed PE strips are filled in the brick joints, and then the single-sided adhesive film is pasted and processed to form, as shown in Fig.
9.
Fig.
9.
(1) ceramic tile plate mold, (2) adhesive film, (3) compaction, (4) reverse molding 3-1-2pe adhesive film vacuum forming method this method is similar to the previous method, but has a high degree of industrialization, The adhesive film is thick and the adhesive effect is good, so the size of the standard adhesive film unit can be enlarged, and it can also be used in slightly larger ceramic tiles..
