Chemical retarder – A chemical retarder is applied to the face of the mould. The strength of this retarder will determine the depth to which the concrete matrix will be prevented from properly setting. After demoulding, this ‘unset’ matrix is removed by pressure washing, thus exposing the course aggregate in the mix and providing the required aesthetic effect.
Polished – A polished concrete surface is achieved by grinding off the surface of the concrete. This is carried out with series of polishing wheels. The first course wheel grinds off approximately 3mm of the concrete surface to expose and cut through the course aggregates. The actual polishing process is then carried out in several stages using different grades of diamond tipped abrasive discs. At each stage a finer hone is achieved and an increasingly higher gloss is obtained. The final level of polishing will be determined at the outset by the client’s requirements.
Acid etched – The effect of acid etching is to remove the outer surface laitance to reveal a fine sandy textured surface finish below. Additionally, by removing the laitance from the outer surface, the potential for discolouration from a variety of sources is lessened.
Sandblasted – Following a strict curing regime, the required surfaces of the element are blasted, under high pressure with sand or grit particles in order to expose the aggregate. The choice of blast media together with the blasting pressure will affect the depth of exposure.
For more information, please get in touch.