Graphic Concrete create GCPro™ for Hämeenlinna Provincial Archive by architects Heikkinen-Komonen
"We decided to coat the facades of the archive with graffiti. This black national memory stick is embroidered with tags found in the depths of the archive: from peasants' bookmarks and the letters of kings to contemporary Internet signs. This was made possible by graphic concrete technology." Mikko Heikkinen, architect.
The building contains three functional units. Above the transparent and colorful ground floor is a three floor-high solid archive box, which is covered with graphic concrete elements on both the exterior and the interior.
According to the architects Heikkinen-Komonen, the archive 'is an important public institution, that contains our collective memory', so it deserved a significant place in the cityscape. The design uses tags and marks found throughout the archive's documents. Graphic designer Aimo Katajamäki was invited to join the project to bring out the collective memory as a pattern design with the graphic concrete technology.
In this project, the realization of the architect's vision became a reality through the use of graphic concrete technology. Graphic concrete is a modern way to produce exposed aggregate concrete and is a patented technology invented by interior architect Samuli Naamanka. The architect's design, the graphics, are produced by printing the design with a graphic concrete surface retarder. This allows the architects to create a design of their own.
The concrete is cast the same way as the traditional exposed aggregate concrete. The graphic concrete method allows the printed membrane to be added to the bottom of the mold table. The concrete is cast on to the membrane. The unset concrete surface is then high-pressure washed, revealing the fine aggregate finish. The actual pattern on the surface of the concrete is the result of the contrast between the fair face finish and the exposed aggregate.
The graphic concrete method of printing a retarder on the membrane does not emit any harmful gas or chemicals and is safe for the workers in production. The used membrane may be disposed of in three alternative ways: as mixed waste, burnt in an appropriate manner or cleaned and recycled. A retarder was specially developed for the use of white cement.