Concrete Surface

Concrete Surface

The impermeability and appearance requirements for concrete surfaces vary widely. Detailed planning and execution of the structure are required to meet these requirements.

Maximum surface impermeability is essential for all durability requirements. The attack always comes from outside to inside. Over vibration or inadequate curing weakens these zones. High quality appearance requirements have led to the production of so-called “fair-faced” concrete.

Appearance of concrete surfaces

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 release agent

·     Select a suitable placement method

·     Use form liners if necessary

·     Consider any necessary retouching

·     Color 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:

Exposed aggregate concrete

Exposed aggregate concrete is a popular surface design feature, e.g. for retaining walls, façade panels, garden features etc.

The aggregate structure is exposed on the surface by washing off and out. This requires surface retardation, which must be effective down to several mm.

In correctly designed exposed aggregate concrete, 2/3 of any single coarse aggregate is still within the hardened cement matrix.