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

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• Technical Characteristics
• Features & Benefits
• Recommendations
• Application
• Precautions to be taken During and After Application
• Cleaning
• Consumption
• Technical Data

Technical Characteristics

Mapegrout Hi-Flow when mixed with water, becomes a highly fluid mortar, suitable for pouring into formwork without separation of the aggregates even when forming great thicknesses.

If Mapegrout Hi-Flow is prepared by only adding water, it must be cured under damp conditions in order to guarantee that the product’s expansive properties develop completely and correctly. However, it is not easy to ensure these conditions on site.

To guarantee the expansive properties of Mapegrout Hi-Flow in the open air, 0.25% of Mapecure SRA, a special admixture which has the property of reducing both plastic and hydraulic shrinkage, may be used to great advantage by adding it to the mix.

Mapecure SRA has a very important role to play, in guaranteeing better mortar curing. When Mapecure SRA is mixed with Mapegrout Hi-Flow, it is considered a technologically advanced system, as the admixture has the capacity of slowing down the evaporation of the water from the mortar and of promoting the development of hydration reactions.

Mapecure SRA acts like an internal curing agent and, due 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 Mapecure SRA when environmental conditions permit an optimal curing.

Mapegrout Hi-Flow meets the requirements defined by EN 1504-9 (“Products and systems for the protection and repair of concrete structures - Definitions, requirements, quality control and evaluation of conformity - General principles for the use of products and systems”) and the minimum requirements claimed by EN 1504-3 (“Structural and non structural repair”) for structural mortars of class R4.

Mapegrout Hi-Flow is recommended for thicknesses up to 40 mm thick. For greater thicknesses, it is recommended to add suitable graded aggregates from 30 to 50% by weight of the product, only after consulting our Technical Services Department.

If higher flexural and impact resistance are required, Mapegrout Hi-Flow TI 20 should be used, castable, shrinkage- compensated, fibre-reinforced, high-ductility cementitious mortar with stiff steel fibres.

Features & Benefits

Mapegrout Hi-Flow, once cured, has the following qualities:

• High flexural and compressive strength
• The modulus of elasticity and coefficients of thermal expansion and permeability to water vapour are similar to those of high quality concrete
• Waterproof
• Very high adhesion to old concrete, when it has been saturated with water beforehand and to reinforcing rods especially if they have been treated with Mapefer or Mapefer 1K
• High resistance to wear from abrasion

Recommendations

• Do not use Mapegrout Hi-Flow on smooth concrete surfaces; roughen them to reach the sound, resistant and rough substrate with more than 5 mm coarseness and insert reinforcing rods if needed
• Do not use Mapegrout Hi-Flow for precision anchoring (use Mapefill)
• Do not use Mapegrout Hi-Flow for applications by spray or trowel (use Mapegrout Thixotropic)
• Do not add cement or admixtures to Mapegrout Hi-Flow
• Do not add water after the mix has begun to set
• Do not use Mapegrout Hi-Flow at temperatures below 5°C
• Do not use Mapegrout Hi-Flow if its packing has been damanaged or if it has been opened prior to use

Application

Preparation of the substrate

• Remove degraded and loose concrete until the substrate is sound, resistant and rough, with more than 5 mm coarseness. Any previous restoration work which is not soundly bonded should also be removed
• Clean the concrete and reinforcing rods by sandblasting, to remove all dirt, rust, cement laitance, grease, oil, and previously applied paints
• 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

Preparing the mortar

Pour 3.25-3.5 litres of water into a cement mixer and then slowly add Mapegrout Hi-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% by weight of the mortar (0.25 kg every 100 kg of Mapegrout Hi-Flow).

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 has a pot life of 1 hour at +20°C.

The expansion of Mapegrout Hi-Flow has been calculated to compensate for hygrometric shrinkage.

To be effective, the forces of expansion must be countered with suitable reinforcement or formwork around the substrate.

Without formwork, Mapegrout Hi-Flow can only be applied in thicknesses greater than 40 mm on the condition that reinforcing rods have been fixed. The reinforcement cover must be at least 20 mm thick.

Smaller thicknesses can be applied without reinforcement as long as the substrate is sufficiently rough to be able to counter the expansion.

The expansion phase is completed during the first days of curing.

Applying the mortar

To facilitate the expulsion of air, pour Mapegrout Hi-Flow continuously into the formwork by one side only.

Water from Mapegrout Hi-Flow must not be absorbed by the formwork, which we recommend to be pre-treated with a form release oil (e.g. MAPEI’s DMA 1000 Form Release Agent).

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.

The repair process is complete when a coat of Elastocolor Paint is applied on the surfaces.

Precautions to be taken During and After Application

• To prepare the mix, only use bags of Mapegrout Hi-Flow which have been stored on their original pallets.
• In hot weather, store the product in a cool place and use only cold water to blend the mortar.
• In cold weather, store the product in a place which is protected from frost at a temperature of +20°C, and use tepid water to blend the mortar.

• After laying Mapegrout Hi-Flow, we recommend that it is cured carefully, especially in hot or windy weather, to avoid the water evaporating too quickly and causing the formation of surface cracks due to plastic shrinkage. Spray water on the surface after 5-8 hours of laying the mortar, and repeat the operation every 3-4 hours for at least the first 48 hours.

  As an alternative, after tamping the mortar, spread on a layer of Mapecure E anti-evaporation treatment, water-based emulsion with a low-pressure pump, Mapecure S solvent-based curing film for mortar and concrete or Elastocolor Primer solvent-based, high-penetration primer for absorbent substrates and curing agent for repair mortar. Mapecure E and Mapecure S, as with all the best quality products in the same category which are currently available on the market, impede bonding of successive coating layers. Therefore, if a smoothing layer or paint is to be applied later, they must be completely removed by sandblasting. If Elastocolor Primer is used as an anti-evaporation treatment, on the other hand, a final protective layer of Elastocolor Paint or Elastocolor Rasante may be applied directly on the treated surface without having to remove it.

Cleaning

Before hardening, the mortar can be cleaned from tools with water. After setting, cleaning is very difficult and it can only be removed mechanically.

Consumption

Approx. 21 kg/m² per cm of thickness.

Technical Data