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Concrete refurbishment using polyurea and crack injection

Concrete refurbishment and concrete repair

Concrete is one of the most widely used construction materials, amongst other things since it is cheap and is easy to manufacture. Unfortunately, concrete is subject to relatively fast progressive ageing if it is exposed to environmental effects and the correct measures are not taken to protect it. After only a few years or decades, the first signs of damage start to show. Crumbling parts and cracks don't just look unsightly, they can also become safety hazards. Concrete structures like parking garages, the tanks of sewage treatment plants or biogas plants are at particular risk and must be refurbished frequently.

Refurbishing concrete and reinforced concrete

If the work in question is not just of a minor cosmetic nature, concrete refurbishment should only be carried out by experts. Depending on the damage pattern, different filling and coating materials are used to refurbish the concrete or reinforced concrete.

Before starting refurbishment of the concrete or reinforced concrete, tests should of course be conducted to establish how compatible these materials are with the old fabric of the structure. Using WIWA equipment, it is possible to carry out much of the refurbishment work.

Concrete refurbishment by crack injection/injection with artificial resins

It is possible to fill deep cracks in concrete sections by injecting liquid dual-component plastic material at high pressure. Dual-component polyurethane resin is a popular sealing material in concrete refurbishment, since it has excellent adhesion properties and mirrors deformations of the concrete sections. In the case of cracks that jeopardise the stability of the structure, the concrete is often refurbished using high-strength epoxy resin that can reestablish the concrete's tensile strength.

When refurbishing concrete using injection, the resin is filled under high pressure using filler necks known as packers. When doing this, adhesive or drill packers are generally used, which can be stuck on or screwed in.

These types of injections are also ideally suited to seal structures in contact with the ground such as concrete base plates from rising seepage water using a horizontal barrier.

Refurbishment of concrete and reinforced concrete by coating with polyurea

Coating with polyurea is an excellent way to protect concrete or reinforced concrete from the effects of the environment. Polyurea reacts in a few seconds and the affected surfaces can be used only a few minutes after the application is completed. Apart from this, polyurea is solvent-free and proof against many aggressive materials, abrasion-resistant and not sensitive to damp.


Due to its high elasticity (crack covering), in particular, polyurea is highly suitable for refurbishing and coating concrete structures. Correct concrete refurbishment by coating with polyurea is, of course, conditional on the surface being pre-treated and an appropriate primer being applied. Regardless of whether you are refurbishing cisterns, swimming pools, sewage treatment tanks or flat roofs, using polyurea you can achieve excellent concrete refurbishment results.

Areas in which concrete refurbishment or reinforced concrete refurbishment will be necessary

Concrete structures/buildings must be sealed against soil moisture as well as upward or downward pressing water. Concrete filter beds, cisterns and drinking water tanks can be coated to guarantee durability. Swimming pools and structures that are covered with earth must often be refurbished too. Concrete bridges, tunnels, facades, silos and cooling towers frequently show signs of damage to concrete sections that must be refurbished using appropriate methods. Shrunk and sealing crack refurbishment using injection can be used in an excellent way in building construction, civil engineering, tunnel construction and bridge building.

Dam refurbishment: Hard-core concrete refurbishment

The French Alps are part of the Western Alps and the highest peak, Mont Blanc, is a world famous paradise for winter sports lovers. Apart from this, the entire alpine region is a gigantic energy store with many dams that are used to supply drinking water and to generate water power to supply electricity. The concrete structures that are needed for this must be inspected on a regular basis and the concrete must be refurbished. When inspecting the Girotte dam near Hauteluce in Savoy in the French Alps, serious defects were discovered in concrete. This meant that the concrete had to be refurbished. The 510m-long dam wall that is 48.5 m high was completed in 1948. Refurbishing the concrete makes particular demands on the people involved and the material they use. In addition to a number of massive cracks, it was also established that the concrete was considerably prematurely aged. The uncontrolled loss of water was just another of the problems with this structure. After removing the loose concrete sections in the cracks and filling them with a special adhesive, acrylate gel was injected to close concealed and/or inaccessible cavities in the concrete. To protect the aged concrete at the weak points, the building contractor SPIE decided to use Polyura PC 4840 Purea material by Dratec. The French company chose to use the powerful WIWA DUOMIX PU 460 for the application technology. Michel Laksander, WIWA representative in France, dealt with the first use on-site to ensure reliable coating of this project and all future ones with SPIE.

WIWA thick layer and mortar pumps

Using the WIWA thick layer/mortar pumps, it is possible to process epoxy- and water-based high-density materials and mortars like cement slurry, filled vinyl esters or cement-bound fire protection materials. By contrast with screw pumps, WIWA high-density material pumps can be easily flushed through and cleaned with thinner. This makes the pump highly suitable for processing epoxy-based materials too. Thanks to the use of quick connectors, the material pumps, which consist of only a few parts, can be very quickly dismantled, cleaned and reassembled – this is particuarly important with the short processing times. You can easily remove the feed funnel. Due to fast maintenance, it is possible to considerably reduce downtimes, particularly under on-site conditions. Our large-volume pumps have extra-large outlets and have very low wear even in the case of high material throughput due to the slow pump speed.

PU foam processing using the DUOMIX PU 280

The WIWA DUOMIX PU 280 has been specially developed for processing PU foams, e.g. in roof refurbishment, hollow space insulation and heat and noise insulation. It can be used on a flexible basis. The powerful material flow heater ensures short material heat-up times.

Processing polyurea using the WIWA DUOMIX PU 460

The powerful WIWA DUOMIX PU 460 is the ideal system concept for applying polyurea and PU foam in the field of concrete refurbishment too. With powerful material flow heaters, phase monitoring, differential pressure shut-down and control of the mixing ratio the PU 460 offers high process reliability in all fields of application. There is an almost free choice of mixing ratio from 1:1 to 10:1, which means that nearly any form of mixing used for in-situ foam or polyurethane/polyurea elastomers can be applied – this is a particular advantage when refurbishing concrete structures.





WIWA DUOMIX PU HYDRAULIC – Protecting – Sealing – Insultating

The WIWA DUOMIX PU HYDRAULIC is the latest and brand-new addition to our DUOMIX PU Series. This hydraulic, compact, versatile and mobile unit is easy to use and can handle all types of polyurethane foam and fast curing polyureas.