Mapei Mapegrout Hi-Flow

Technical Characteristics

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 developed in the MAPEI Research & Development Laboratories

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, 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.

Technical Data

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 Mapegrout Hi-Flow, only after consulting our Technical Services Department.

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

Application Procedure

* To allow expansion in air

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.
• 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. Workability time may be extended by using Dynamon EW liquid admixture, according to MAPEI Technical Assistance recommendations.

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.

The product may be transported using pumping or worm-screw double mixing rendering machine. For further information about mixing and pumping of the product contact MAPEI Building Technical Assistance. Instructions for the preparation of mortar for Lab testing samples can be found in the TECHNICAL DATA section.

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.

Pours thicker than 3 cm must be carried out after placing reinforcement steel rebar of at least 5 mm diameter and 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 Elastocolor Paint

• Pouring into a formwork
• Removing wooden formwork
• Deteriorated concrete structure
• Pouring Mapegrout Hi-Flow into metal formwork
• Restored structure
• Reforming road joints

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.