Mapei Mapegrout T40

Mapei Mapegrout T40 medium strength (40 MPa), shrinkage compensated, fibre-reinforced, thixotropic mortar for repairing degraded vertical or horizontal concrete surfaces.

Mapegrout T40 is a grey powdered mortar composed of cement, graded aggregates and special additives formulated for repairs to degraded concrete surfaces, corners of pillars and beams, tunnels, linings for canals, filling of rigid joints, etc. Mapegrout T40 is mixed with water to form an easy to apply thixotropic mortar that can be applied without slumping even in substantial thickness's on vertical surfaces without formwork.

When fully cured, Mapegrout T40 has moderate flexural and compressive strength; a modulus of elasticity, thermal expansion coefficient and permeability coefficient similar to that of medium quality concrete; is waterproof and has excellent adhesion to existing concrete surfaces.

Best Uses

Use Mapei Mapegrout T40 for vertical or horizontal repairs to degraded concrete surfaces, balconies damaged by rusted reinforcing bars, reconstruction of concrete coverings of reinforcing bars, repair of surface irregularities including exposed aggregate, joints between new and old concrete, holes in formwork concrete, protruding steel, etc.

Application

Substrate preparation
Remove degraded and loose concrete until the substrate is solid, resistant and rough. Any previous repair work that is no longer thoroughly bonded must also be removed. Sandblast the concrete and the reinforcing bars until they are free of dirt, rust, cement laitance, grease, oil, varnish or old paint. Saturate the substrate with water. Before repairing with Mapegrout T40, wait until the excess water has evaporated. To facilitate the elimination of free water, use compressed air if needed.

Preparing the mortar
Pour into the mixer the amount of water needed to obtain the consistency required for the application.

APPLICATION per 25-kg bag
Trowel from 3.8 to 4.0 litres of water
Spray from 3.9 to 4.1 litres of water

Start the mixer and slowly add the Mapegrout T40 to the water in a continuous flow. If improved open-air curing of the mortar is required, add Mapecure SRA at the end of the mixing phase at a dosage of 0.25% in weight of the mortar (0.25 kg every 100 kg of Mapegrout T40). Mix for 1 to 2 minutes, then make sure the mix is well blended. Scrape any unblended powder from the bottom and the sides of the mixer. Mix again for another 2 to 3 minutes. Either a cement mixer or a drill equipped with a mixing attachment may be used, according to the amount of material to be prepared. Mixing must be carried out at low speeds, to avoid air being entrained into the mix.

Avoid mixing manually unless absolutely necessary. If so, mix small amounts at a time for at least 5 to 6 minutes until a completely homogeneous paste is obtained. Keep in mind that mixing by hand requires a larger amount of water. This adversely affects several of the mortar’s characteristics, including mechanical strength, shrinkage, impermeability, etc. Mapegrout T40 remains workable for approximately 1 hour at +20°C. The expansion of Mapegrout T40 is calculated to compensate for plastic shrinkage. For it to be effective, the substrate needs to be adequately reinforced with rebars or forms. Applying Mapegrout T40 without formwork in thicknesses of more than 2 cm should be done only after reinforcing and roughening the surface of the concrete, taking care to cover the reinforcement with a layer at least 20 mm thick. Lower thicknesses can be applied without reinforcing as long as the substrate has been substantially roughened to counter the expansion. The expansion phase ends during the first days of curing.

Application procedure
The mortar can be applied with a trowel or gauging trowel without form work even on vertical surfaces or ceilings in maximum thicknesses of 30 to 35 mm per layer. Mapegrout T40 can also be spray applied, using Turbosol or Putzmeister type equipment, excluding continuous mixing machines. Reinforcing bars must be previously treated with Mapefer or Mapefer 1K Zero before applying the Mapegrout T40. Where necessary, apply a second layer of Mapegrout T40 before the previous layer has finished setting (within 4 hours at +23°C). After completing repair work, the surfaces may be skimmed with Monofinish, Mapefinish, Planitop 200 or with an elastic skimming product such as Mapelastic or Mapelastic Guard. Coloured Elastocolor Paint may then be applied to create a protective finish.