The underlaying concrete must be C25/30, at least, and the surface must be free of poorly attached concrete. The surface is cleaned of old coatings, cement glue, and other substances that worsen adhesion.
Water requirement approx. 10-12 %. Add the dry material to the water and mix with a concrete mixer for around ten minutes. With a power mixer, around one to three minutes of mixing is sufficient. Let the mass stand for approximately 5 minutes, and mix it briefly anew. Find the correct consistency at this stage by gradually adding the rest of the water. We do not recommend adding all of the water right at the start. The finished concrete remains workable for approximately one hour.
Pretreatment fresh casting
The strength of the underlaying concrete must be C25/30, at least. When the underlaying concrete can withstand walking on it, lapping with a plate can be started. Lapping is continued until the High-performance concrete is applied. High-performance concrete is transferred by a trolley or pump. The pump needs to be powerful enough and the hose diameter no less than 50 mm. Spreading by a straightedge or vibrating blade. The surface is lapped with a plate and finished with a blade.
Pretreatment hardened concrete base
The base has to be solid and clean, with the strength of at least C25/30. The most recommended treatment from the point of view of adhesion is mechanical milling. To avoid cracks, it is important to wet the base carefully on the previous day, specifically. Onto the base, damp enough to be darker in colour, a 2-component Fescon Bedding mortar 2-K is spread. The amount of adhesive plaster 2-3 kg/m2 (of dry product). The adhesive plaster must not set before the High-performance concrete is applied. Variations in the amount of adhesive plaster cause variation in the time of starting surface treatment. Spreading, lapping, and finishing as for fresh casting, for the most part. However, finishing that continues for too long can weaken the adhesion to the base.
Casting work is done according to the normal working methods, the instructions of the designers and official regulations.
Note! High-performance concrete is removed from walls and pillars as the underlaying concrete. The same is true for expansion joints with regard to the underlaying concrete.
Immediately after finishing, Fescon Curing Compound is spread onto the surface by using an appropriate working method. Consumption approx. 0.1 kg/m2. The next morning the surface is additionally wetted and covered in plastic. Aftercare must continue according to the BLY aftercare instructions and for at least 7 days.
Tools are washed with water.
Storage and handling of waste. See the separate storage and disposal instructions https://www.fescon.fi/en/material-bank