Mapegrout Fast-Set Rapido

For rapid concrete repairs on exterior vertical or horizontal surfaces, Mapegrout Fast-Set Rapido provides a structural, shrink-compensated, and fibre-reinforced mortar that sets in 30 minutes. It is formulated for the fast restoration of deteriorated concrete structures, edges of beams, pillars, and balconies damaged by reinforcing rod oxidation, as well as rapid repairs to industrial concrete flooring, concrete pipes, and brick pointing.

High-build thixotropic performance

This pre-blended hydraulic mortar is thixotropic, allowing installers to trowel applications up to 20–25 mm thick on vertical surfaces in a single layer without slumping. The shrinkage-compensated formulation prevents cracking during the rapid drying phase. Once cured, it achieves an R3 structural rating under EN 1504-3, delivering high compressive and flexural strength alongside low capillary water absorption to protect internal steel reinforcement from future corrosion.

Numbers that matter

• 30-minute setting time: Fast initial set allows the mortar to support mechanical loads and light traffic within 2 to 3 hours of application.
• > 40 MPa compressive strength: Meets and exceeds the Class R3 structural requirement (≥ 25 MPa) at 28 days, beginning with a rapid strength gain of > 10 MPa after just 3 hours.
• 10-minute pot life (at +20°C): A tight mixing and application window requiring installers to prepare only what can be placed immediately.
• 18 kg/m² per cm consumption rate: Provides a predictable coverage floor for calculating material requirements on deep structural patches or floor repairs.
• > 1.5 MPa bond strength: High-adhesion performance under EN 1542 tests to ensure permanent integration with prepared, damp concrete substrates.

Where to use it

• Restoration of damaged concrete pillars, beams, and balcony edges.
• Fast repairs to industrial concrete floors requiring quick return to service.
• Sealing surface cracks in concrete and cement renders.
• Fast smoothing of surface defects in fresh concrete pours, including aggregate bridging, shrinkage joints, and formwork spacer holes.
• Assembly and edge repair of concrete pipes.
• Pointing between bricks on structures prior to waterproofing with Planiseal 88.

Installation and application

Substrates must be mechanically prepared to a rough, sound finish with surface irregularities at least 5 mm deep to expose the aggregate. All concrete surfaces must be thoroughly wet with water, allowing excess water to evaporate so the substrate is damp but free of puddles. For optimal adhesion, brush on a bonding slurry composed of 1 part Mapegrout Fast-Set Rapido to 0.24–0.25 parts water immediately before trowelling the mortar mix.

Mix a 25 kg bag with 3.75–4 litres of clean water using an electric mixer until smooth. Apply with a float or trowel to the wet slurry. For repairs deeper than 2.5 cm, apply multiple layers at 15-minute intervals, scoring each intermediate layer with a 10 mm notched trowel. Keep restored areas damp for at least 24 hours, or protect floor repairs with polyethylene sheets or wet bags to prevent rapid evaporation.

Limitations

• Do not add extra water to the mix after setting has commenced in an attempt to restore workability.
• Do not add cement, lime, gypsum, or any other admixtures to the powder.
• Do not apply to dry, dirty, or unprepared surfaces.
• Do not use for precision machinery or column anchoring; use Mapefill or Mapefill R instead.
• Do not apply with plaster sprayers; use Mapegrout Thixotropic instead.
• Do not apply in temperatures below +5°C or above +35°C.
• May undergo colour variation after hardening; it is not recommended for use as an exposed aesthetic façade finish.