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Crackfilling Chemicals from Mapei


The problem of cracking in building is becoming a difficult puzzle for engineers nowadays. Cracking is an unavoidable response of any structure while designers are trying to eliminate many of the causes of cracking and design tolerance for other factors. We all want our building structurally safe, but it is not so easy. Some faulty steps during construction and some unavoidable reasons different type of cracks starts to appear on various structural and non-structural parts of the building. So, timely identification of such cracks and adopting preventive measure are essential. The repair materials and repair technique are different depending upon forms of cracks according to their positions in structure. Some types of cracks seriously need attention as they are structurally hazardous.  Let’s us discuss solutions from Mapei for repairing cracks.

MAPEFLEX AC4- Mapeflex AC4 is a one-component product based on acrylic resins dispersed in water and is a thixotropic paste that is easy to apply on both horizontal and vertical surfaces. Mapeflex AC4 is used to seal internal and external expansion and construction joints subject to a medium amount of movement and surface cracks in all types of absorbent building materials.

Mapeflex AC4 seals remain unaltered even after many years of exposure to severe weather conditions, industrial environments and thermal gradients. They remain flexible in temperatures as low as –30°C and resist temperatures up to +80°C (+100°C for short periods). Their resistance to chemical agents (for diluted acids and alkalis only) is good. However, given the large number of products and operating conditions, it is best to carry out a few tests before using Mapeflex AC4. Its resistance to water is good as long as it is not permanently immersed. Before painting over Mapeflex AC4 it must be fully polymerised. We recommend carrying out preliminary tests to make sure the sealant and paint are compatible. Mapeflex AC4 complies with EN 15651-1 norm (“Sealants for façade elements”) with performance rating F-EXT-INT.

Application  areas:

Seal joints between precast concrete panels with movement up to 12.5%.

Seals between prefabricated panels in concrete, wood and gypsum board.

Seals between elements in concrete, plaster, brickwork, light-weight cement, wood, natural stone, etc.  Airtight and waterproof seals between wooden frames and masonry.

Flexible seals between doors, roller-blind caissons and masonry, and between walls, ceilings, wooden panels and insulation panels.

Sealing joints between insulation panels and external building features (doorsteps, windows, window-sills, cornices, etc.) in thermal cladding systems.



EPOJET LV- Two-component epoxy resin with a very low viscosity for injecting into micro-cracks, also on wet surfaces.

Once mixed, Epojet LV becomes a very fluid liquid that can easily penetrate even in microcracks. Epojet LV polymerizes without shrinkage and once hardened is waterproof and resists chemical agents present in the atmosphere. Epojet LV has very good insulating properties and high mechanical strength. Epojet LV 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 1504-5 (“Concrete injection”).

Application  areas:

Structural repair of beams, pillars and cracked floors by low pressure injection.

Reinforcement of beams and floors by injection with the bétonplaqué method, when the plates to be bonded are fitted with lateral flaps and it is therefore impossible to apply Adesilex PG1 or Adesilex PG2.

Repair of architectural concrete, wall coverings and architectural elements that are crumbly. Structural consolidation and restoration of civil and industrial road constructions and underground works that show signs of microcracking.

Sealing of cracks in cementitious screeds.

Restoration, by injection, of concrete structures damaged by earthquakes, settlements or impacts.

FOAMJET- High viscosity ultra rapid setting two-component polyurethane resin, to be injected for consolidating and waterproofing of structures subject to strong water ingress.

After having mixed the two components together in the ratio 1:1 by volume, with a special pump equipped by static helicoidal mixer, Foamjet T forms a polyurethane foam of great strength. Due to its rheological properties, Foamjet T can also penetrate through small cracks and sealing them even if they are subject to water infiltrations. At the end of the setting time, within a few seconds, depending on the temperature, Foamjet T becomes completely waterproof and ensures an adequate consolidation to the treated structure. Foaming/hardening reaction takes a very few seconds but, either upon peculiar requirements or in presence of low application temperatures (lower than +15°C), it is possible to reduce reaction time by adding, into the Foamjet T part A, a small quantity (0.5-1.5% by weight) of a proper catalyst Foamjet AKS.

Application uses:

  • Waterproofing tunnels subject to high pressure water ingress through possible cracks or in fissures between keystones.
  • Waterproofing shafts or hydraulic structures with high pressure water ingress through working joints or cracks.
  • Repairing cracks in dams, channels and bulkheads when permanently immersed in water.
  • Sealing cracks in floorings or slabs that are damp or saturated with water.

For further details :

Mapei Construction Products India Pvt. Ltd.
A01, B01, 1st Floor, Solus Jain Heights
1st Cross, J C Road, Bangalore 560 002
Ph.: 080 22221820
Email: infoindia@mapei.co.in
Website: www.mapei.co.in


  1. Wchich of all the products described in Masterbuilder, gives the best results for sealing cracks on roof surface?


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