Exposed Aggregate Concrete is an architectural design concrete that makes aggregates appear at the concrete’s surface and thus particularly visible. To achieve this, the cement paste at the concrete’s surface is washed out after concreting. For surface treatment, there are two methods: either by means of a high-pressure water jet applied onto the already hardened concrete or with the help of a surface retarding agent that causes the solidification of the processed surface to slow down and hence enabling a subsequent wash-out or brush-off of the cement slurries.
The selection and composition of the aggregates will define the desired structure and surface coloration.