TECHNICAL SOLUTIONS > REPAIRING - PAINTING > Repairs of concrete elements > Repairing of damaged concrete elements by grouting with concrete or high strength mortar

Repairing of damaged concrete elements by grouting with concrete or high strength mortar


In repairs - reinforcements of this kind, the concrete for casting must have the appropriate fluidity and ability to penetrate, in order not to leave any spaces during concreting, since grouting is generally performed at 10-12 cm of thickness, making spreading of the concrete difficult. When it is necessary to grout at thin layers of 4-8 cm thickness, which makes casting of concrete very difficult, a liquid mortar of great fluidity and high strength is required.

Additionally, the concrete or mortar for casting must bond efficiently to the existing concrete so that the formation of a monolithic element consisted from the old and new concrete, is ensured.



Normal grouting at 8-15 cm thickness
The filling material is concrete to which BEVETOL-SPL or REOTOL-SPL concrete superplasticiser is added to ensure the desired fluidity of the concrete poured, while increasing its strength, by virtue of the great compression achieved.


Grouting at thin layers of 4-8 cm thickness
MEGAGROUT-100, high performance grout is used as the filling material. It has great fluidity and very high strength.



Substrate preparation

  1. Any broken concrete parts are removed and cavities are created in the old concrete in order to improve bonding of the concrete to be poured.

  2. The existing reinforcement is exposed, wherever necessary.

  3. The surface of the existing concrete is mechanically roughened (e.g. by sand blasting).

  4. Subsequently the existing concrete is washed with plenty of water under pressure.

  5. The form-work is prepared and the new reinforcement is placed to the engineer's statics study and is joined to the old with pegs and dowels.

  6. Wherever possible, the old concrete surface is coated with DUREBOND, epoxy resin - bonding agent, to ensure a perfect bond between the old and new concrete.


Normal grouting at 8-15 cm thickness
Following the above preparation the concrete casting, is carried out with the addition of BEVETOL-SPL superplasticiser in the proportion of 0,6-0,8% by cement weight, or REOTOL-SPL superplasticiser in the proportion of 1,2-1,7% by cement weight, until an approximate 20 cm slump of the concrete results. Vibration of concrete during the casting is essential in order to achieve better compression of the concrete.


Grouting at thin layers of 4-8 cm thickness

  1. Where MEGAGROUT-100 will be cast into forms, it is recommended that the j oints between form-works are sealed with AQUAFIX rapid-setting cement or RAPICRET fast-setting patching mortar, because the material is so fluid and fine-grained that it may otherwise escape through them.

  2. The content of a 25 kg bag of MEGAGROUT-100 is added to 3 kg of water and mixed thoroughly with a low revolution mixer, until a homogenous mass is formed. Then a small quantity of up to 0,5 kg of water may be added until the desired fluidity is achieved.

  3. The mortar is cast, taking care to avoid trapping of air. It must be ensured that the mortar has filled the entire space between the form-work and the existing construction.
    Consumption of MEGAGROUT-100: 21,5 kg/m2/cm thick coat or 2,1 kg to fill a volume of 1 litre.

  4. Exposed to the atmosphere surfaces must be kept wet for at least 24 hours, by covering them with wet linoleum or polyethylene sheets.



  • Temperature during application must be between +50C to +350C.

  • The strength of the concrete to be cast must be greater than that of the old concrete by at least 10 N/mm2.

  • The particle size of the inert materials in the concrete to be poured must not exceed 20 mm.

  • MEGAGROUT-100 can be applied at a maximum thickness of 10 cm per layer.

  • Material that has started to set must not be softened again with water.

  • The product keeps its fluidity for approx. 60 minutes at temperatures between +150C to +250C.

  • At high temperatures, storage of the bags in a cool place is recommended, as well as mixing the material with cold water in order to achieve the appropriate fluidity for a sufficient length of time (about 60 minutes).

  • At low temperatures and whenever fast development of strength is required, mixing of the material with lukewarm water and protection from cold by putting thermal insulating covers over the formwork are recommended.

  • The product contains cement, which reacts as alkaline with water and is classified as irritant.

  • Consult the directions for safe use and precautions written on the packaging.