Mapegrout Gunite is a one-component premixed cementitious mortar composed of hydraulic binders, silica fume, select aggregate and special additives manufactured according to a formula.

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• Technical Characteristics
• Features & Benefits
• Recommendations
• Application
• Cleaning
• Consumption
• Technical Data

Technical Characteristics

When mixed with water Mapegrout Gunite acquires a thixotropic consistency and can therefore be easily applied on vertical surfaces, on soffits of tunnels and bridges in substantial thickness.

Mapegrout Gunite meets all the main principles of EN 1504-9 (“Products and systems for the protection and repair of concrete structures: definitions, requirements, quality control and conformity assessment. General principles for the use of products and systems”), and the minimum requirements for EN 1504-3 (“Structural and non-structural repairs”) for R4 class structural mortars.

Features & Benefits

After setting, Mapegrout Gunite:

• Has high flexural and compressive strength
• Is watertight
• Adheres very strongly to old concrete, provided the concrete is first saturated with water, and to reinforcement bars, especially when they are first treated with Mapefer or Mapefer 1K
• Resists sulphates
• Resists carbonation
• Resists freeze-thaw cycles in the presence of sodium chloride in compliance with SIA 162/1, section 9

Recommendations

• If the layer applied is thicker than 30 mm, prior to application, we recommend creating a very rough surface on the substrate inserting steel retaining rods.
• Mapegrout Gunite is supplied ready to use and no other materials are required on site.

Application

Preparation of the substrate (masonry, stone and concrete)

• Surfaces must be free of oils, grease, dirt, and loose material
• Remove the deteriorated concrete down to where the substrate is solid, resistant and rough-textured. Any previous repairs that are not perfectly bonded must be removed
• Remove dirt, rust, cement laitance, grease, oil, varnish or paint from the concrete and rebars with a high pressure cleaner or by sandblasting
• Saturate the substrate with water
• Before beginning repairs with Mapegrout Gunite, wait until the excess water evaporates. If needed, remove free water using compressed air
• If there are clear signs of water seeping in, we recommend applying Lamposilex to seal off the seepage points

Dry application of the mortar

Mapegrout Gunite can be applied exclusively with a special dry mix spray machine and only after the surface has first been saturated with water. This preliminary operation can be carried out by using the hose of the spray machine to spray water on the substrate.

When mixed with water, which takes place inside the nozzle of the hose, Mapegrout Gunite acquires a thixotropic consistency and can be easily applied in thicknesses up to approx. 40 mm per coat without forms.

For thicknesses greater than 40 mm, apply in several coats. To facilitate bonding between coats we recommend leaving the surface of the previous coat rough and then spraying it lightly with water when it has hardened.

After applying the last coat, smooth with a float (after initial setting and before hardening). For a finer-textured finish, use Mapefinish, Monofinish or Planitop T.

Recommended equipment

OCMER type OCM-030 compact or OCM-045.

Damp application of the mortar

Once the substrate has been prepared (as described in the previous paragraph), damp application of the mortar may be carried out. We recommend adding water at a rate of 13% in weight of the mortar (3.25 l per sack) to give an ideal consistency for laying.

After mixing, apply the mortar by dry spraying, or with a piston or worm screw-type rendering machine, such as a Turbosol or Putzmeister.

If shorter setting times are required, damp application of the mortar may be carried out, but by adding a setting accelerator in the lance nozzle while spraying.

Cleaning

The mortar can be removed from tools with water if it has not yet hardened.

The dry mix machine can be cleaned using high pressure air only. The nozzle should be cleaned with water.

Consumption

Approx. 20 kg/m² per cm of thickness (about 22 kg/m² per cm of thickness considering a 10% rebound).

Technical Data