Mapei - Planitop is a structural R4-class, rapid setting, shrinkage-compensated, thixotropic, fibre-reinforced, cementitious mortar, applied in a single layer from 3 to 40 mm thick, for repairing and smoothing concrete.

Recommended Use

• Rapid repair work on deteriorated concrete beams, pillars, buffer walls, cornices, edges of balconies and structural members and elements that require the use of mortar with high mechanical performance characteristics.
• Quickly smoothing over surface defects in cast concrete, such as deep gravel clusters, spacer holes, second pours, etc. before painting the surface.
• Repairs and structural strengthening of concrete.
• Repairing precast concrete members and elements.
• Repairs to concrete damaged by rusty reinforcing bars due to carbonation.

Characteristics

Planitop Smooth & Repair R4 is a one-component, thixotropic mortar with very low emission of volatile organic compounds (EMICODE EC1 Plus) made from special, highly reactive hydraulic binders, fine selected aggregates, synthetic polyacrylonitrile fibres, synthetic polymers and special admixtures according to a formula developed in the MAPEI Research Laboratories. After mixing, the product forms a mortar with good workability and with setting and hardening times that can be modulated by adding Mapetard ES. It is applied by trowel in a single layer from 3 to 40 mm thick to repair and smooth over concrete. Planitop Smooth & Repair R4 hardens without shrinking and is characterised by its excellent adhesion to concrete substrates.

Once hardened, Planitop Smooth & Repair R4 has the following characteristics:

• excellent adhesion to both old concrete (≥ 2 MPa), if wetted beforehand with water, and to steel reinforcement, especially when treated with Mapefer or Mapefer 1K anti-corrosion and re-alkalising cementitious mortar, certified EN 1504-7 “Corrosion protection of reinforcement”;
• high dimensional stability and, therefore, low risk of cracking and crazing during both the plastic phase and when hardened;
• thermal compatibility to freeze/thaw cycles, measured as adhesion according to EN 1542;
• high resistance to carbonation; 
• impermeable to water. Planitop Smooth & Repair R4 complies with the principles defined in EN 1504-9 (“Products and systems for protecting and repairing concrete structures: definitions, requirements, quality control and conformity assessment. General principles for the use of products and systems”) and the minimum requirements of EN 1504-3 (“Structural and non-structural repairs”) for structural R4-class mortars and the requirements of EN 1504-2 coating (C) according to principles MC and IR (“Concrete surface protection systems”).

Preparation of the substrate

• Remove all deteriorated and loose concrete to form a sound, strong substrate with a rough surface. Any areas previously repaired which are not perfectly adhered must also be removed.
• Remove all dust, rust, cement laitance, grease, oil and paint from the concrete and reinforcement rods by sandblasting or hydro-sandblasting.
• Treat reinforcing bars with Mapefer or Mapefer 1K according to the procedure illustrated in the relative data sheet for each product. Before applying Planitop Smooth & Repair R4 wait until Mapefer or Mapefer 1K are completely dry. 
• Saturate the substrate with water. 
• Before carrying out repairs with Planitop Smooth & Repair R4, wait until any excess water has evaporated off. If necessary, use compressed air to help remove excess water. The substrate must be saturated with water but with a dry surface (s.s.d.).

Preparation of the mortar

Pour approximately 4 litres of clean water into a container and slowly add a 25 kg bag of Planitop Smooth & Repair R4 while mixing. Carefully mix the blend for several minutes then remove any powder which has stuck to the sides and bottom of the container. Add more water to obtain the consistency required without exceeding the recommended amount (approximately 4.1-4.4 litres). Mix again for several minutes to form a well-blended, plastic, lump-free mix. To make it easier to form a smooth, even mix, use an immersion mixer or a drill at low speed with a spiral mixing attachment to avoid entraining air into the mix. Mixing by hand is not recommended, more than the recommended amount of water would be required. If manual mixing is unavoidable, use a trowel and press the mortar against the sides of the container to break down all the lumps.

Planitop Smooth & Repair R4 remains workable for approx. 15 minutes at a temperature of +10 to +25°C. If the workability time of Planitop Smooth & Repair R4 needs to be increased due to specific site requirements or if the weather is particularly hot, the set-retarding admixture Mapetard ES for rapid-setting cementitious mortar may be added to the product. This special admixture, which may be added at a rate of up to one 0.25 kg canister every 25 kg of Planitop Smooth & Repair R4, allows the already excellent workability time of the mortar to be extended by a further 15-20 minutes. Due to its plasticising effect, adding Mapetard ES to Planitop Smooth & Repair R4 allows the amount of mixing water to be reduced by 0.2-0.3 litres. In this case, pour approximately 3.7 litres of clean water and a canister of Mapetard ES into a container and slowly add a 25 kg bag of Planitop Smooth & Repair R4 while mixing. Carefully mix the blend for several minutes then remove any powder which has stuck to the sides and bottom of the container. Add more water to obtain the consistency required without exceeding the recommended maximum amount of 4.1 litres.

Application of the mortar

Apply the mortar with a smooth trowel in a single layer from 3 to 40 mm thick without using formwork. As soon as the mortar starts to set, tamp the surface with a sponge float. The waiting time required before carrying out this operation depends on surrounding weather conditions. To paint and protect the surface, apply a coat of an elastomeric product from the Elastocolor range or an acrylic product from the Colorite range. The finishes available may be chosen from product’s relative colour chart or from a much wider range of shades available using the ColorMap® automatic colouring system. If the structure to be repaired is subject to high dynamic stress, it may be advantageous to apply a 2 mm thick layer of flexible smoothing and levelling compound such as Mapelastic, Mapelastic Guard or Mapelastic Smart before applying the coloured finish. In such cases, Elastocolor Paint must be used for the coloured finishing coat.