Modern architecture is unimaginable without fair-faced concrete. For decades priority was given to the unique load-bearing properties and unequaled cost/performance ratio as a structural building material.
In modern architecture concrete is increasingly used as a design feature as well as for its mechanical properties. This means higher specifications for the finish (exposed surfaces).
There are many ways to produce special effects on these exposed surfaces:
- Select a suitable concrete mix
- Specify the formwork material and type (the formwork must be absolutely impervious!)
- Use the right quantity of a suitable mould release agent
- Select a suitable placing method
- Use form liners if necessary
- Colour using pigments
- Install correctly (compaction, placing etc.)
- Thorough curing
In addition to all of these factors listed, the following are important for the concrete mix:
- Use minimum fines content and a balanced grading curve as used for pumped concrete
- Cement generally > 300 kg/m3
- Allow for the effect of the cement on the colour of the exposed surface
- The water content in a fair-faced concrete requires great care and consistency (avoid fluctuations) and prevent bleeding