Mapei Mapegrout Hi-Flow Zero

Mapei Mapegrout Hi-Flow Zero is a ready-mixed mortar in powder form composed of highly resistant cements, selected aggregates, special admixtures and synthetic fibres.

Best Uses

Mapei Mapegrout Hi-Flow Zero is best used for the repairing of structures where particular thicknesses and the state of deterioration require the use of high-flow mortars.

Some application examples:

• Structural reinstatement of reinforced concrete beams and pillars
• Restoring the lower flanges of pre-stressed concrete beams of viaducts
• Reinstatement of floor beams and slabs after scarification of deteriorated areas
• Restoring concrete floors (industrial, road and airport)
• Grouting rigid joints between concrete elements

Thanks to its particular formulation the product has excellent fatigue behaviour up to at least 300,000 cycles, which gives repaired structures a high level of resistance to cracking, including when subject to dynamic loads induced during normal service conditions. This particular characteristic, together with the requirements of EN 1504, helps increase the durability of elements restored with Mapegrout Hi-Flow Zero. Mapegrout Hi-Flow Zero when mixed with water, becomes a highly fluid mortar, suitable for pouring into formwork without separation of the aggregates even when forming great thicknesses.

To allow the product’s expansive properties to develop fully and correctly, Mapegrout Hi-Flow Zero must be mixed with water and cured in a damp environment. However, it is very difficult to guarantee these conditions on site. Therefore, to allow expansion in the open air, Mapegrout Hi-Flow Zero may also be admixed with 0.25% of Mapei Mapecure SRA. Mapei Mapecure SRA carries out an extremely important role and guarantees better curing of the mortar. When mixed with Mapegrout Hi-Flow Zero, it can be considered a technologically advanced system, as it is able to reduce the rapid evaporation of water and promote the development of hydration reactions.

Mapei Mapecure SRA acts like an internal curing agent and, thanks to its interaction with some of the main components which make up the cement, it helps to reduce shrinkage by between 20 and 50% compared with the standard values of the product without the admix. This reduces the risk of cracking. The product can be used also without using Mapei Mapecure SRA when environmental conditions allow for correct curing.

Mapegrout Hi-Flow Zero, once cured, has the following characteristics:

• High flexural and compressive strength
• Modulus of elasticity, thermal expansion coefficient and permeability coefficient similar to high-quality concrete
• Waterproof
• Excellent bond strength to old concrete, if dampened with water before application, and to reinforcement rods, especially if treated beforehand with Mapefer or Mapefer 1K Zero
• High resistance to wear from abrasion

Mapegrout Hi-Flow Zero is recommended for thicknesses up to 4 cm. For greater thicknesses, it is recommended to add suitable graded aggregates from 30 to 50% by weight of Mapegrout Hi-Flow Zero, only after consulting our Technical Services Department.

Application

Composition of mix:

• 100 kg of Mapegrout Hi-Flow Zero
• 12.5-13-5 kg of water
• 0.25 kg of Mapei Mapecure SRA (optional)

Preparation of the substrate
Remove all deteriorated, detaching or contaminated concrete until a rough, sound and resistant substrate is obtained. Remove any previous repair work or coating if not perfectly adhering to the substrate, using suitable tools (mechanical demolishing, hydroscarifying etc.). Clean concrete from previous scarifying works and clean reinforcing rods from dust, cement laitance, rust, grease, oil, paint and other contaminants through sandblasting and high-pressure water jets. After preparation, the concrete surface to be repaired must be rough, with irregularities at least 5 mm deep and inert fraction exposed to allow correct adhesion of the mortar to the substrate.

Treat any exposed rebar with Mapefer or Mapefer 1K Zero according to the procedure illustrated in the relative Technical Data Sheet for each product. Wait until Mapefer or Mapefer 1K Zero dries. Soak the substrate with water. Allow the excess water to evaporate before pouring in the mix; if necessary, use compressed air to facilitate the removal of the excess water.

Preparation of the mortar
Pour 3.15-3.4 litres of water into a cement mixer and then slowly add Mapegrout Hi-Flow Zero. If improved open-air curing of the mortar is required, add Mapei Mapecure SRA at the end of the mixing phase at a dosage of 0.25% by weight of the mortar (0.25 kg every 100 kg of Mapegrout Hi-Flow Zero). Mix for 3-4 minutes, scrape any unmixed powder off the sides of the mixer and remix for another 1-2 minutes until the mix is fluid and free from lumps. Depending on the quantity being prepared, a mortar mixer or a drilling machine with a stirrer attachment can be used.

Avoid stirring an excess of air into the mix. Mapegrout Hi-Flow Zero has a pot life of 1 hour at +20°C.

Application of the mortar
To facilitate the expulsion of air, pour Mapegrout Hi-Flow Zero continuously into the formwork by one side only. Water from Mapegrout Hi-Flow Zero must not be absorbed by the formwork, which we recommend to be pretreated with a form-release oil (e.g. MAPEI’s Mapeform DMA 1000). The pour does not need to be vibrated. Make sure that all the parts to be repaired have been filled. If necessary, use sticks or rods to tamp the slurry into particularly difficult areas. Pours thicker than 4 cm must be carried out after placing reinforcement steel rebar anchored to the substrate, with at least 2 cm concrete covering.

Lower thicknesses may be carried out without applying reinforcing rods as long as the substrate is roughened with irregularities equal to or greater than 5 mm, in order to counter the expansion of mortar which completes during the first days of curing. To complete the repair cycle paint surfaces using Mapei Elastocolor Paint.