Cementos Molins

How to repair reinforced concrete

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Reinforced concrete plays a very important role in our daily life, since it is present in most building and public works structures.However, although it behaves well in service, its durability is compromised by various pathologies that can affect it. 

The most common and frequent is carbonation, chemical process because of which, the concrete loses the ability to protect the rebar against corrosion. The carbonation advances as a front in the concrete and when it reaches the rebar, in the presence of moisture, begins the corrosion.

The reinforcement, when oxidized, increases its volume producing internal tensions in the concrete that are translated in detachments or breaks, that in the long can weaken the structure.

The corrosion of the reinforcement can also be originated by the action of chlorides, sulfates, …; is what is known as  pitting corrosion (occurs at certain points of the armature, in a discontinuous manner).

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The repair of a concrete consists of four basic operations:

Preparation of the substrate. Mechanically remove deteriorated concrete until reaching a substrate that, in addition to having a pH above 9.5, has a percentage of chlorides below the minimum required.

Protection of reinforcement. The rebar must be exposed on the entire surface where it is oxidized. Clean the oxide layer of the reinforcement with a brush or sand blast and then apply BETOPRIM EPOXI as a protective primer against corrosion.

Filling. Use the repair mortar PROPAM® REPAR 40 to perform the repair. The reinforcement must always be totally covered and all cavities must be completely filled, avoiding the formation of internal voids. Pre-apply the BETOPOX® 93 primer on the surface of the concrete to be repaired. Coat with PROPAM® REPAR 5 to obtain a smoother and thinner surface finish.

Protection of the final surface. The simplest way to protect concrete against carbonation, chlorides and environmental chemical aggressiveness is achieved by a continuous coating of a one coat mortar of the REVAT® range, or by an acrylic coating (BETOPAINT, REVAT® FILM, REVAT® PLAS) .


  • The concrete of the substrate must always be firm (minimum tensile strength of 1 N / mm2), free of cement slurries, oils, grease, debris, old paints, etc.
  • Concrete repair can also be carried out with the product PROPAM® REPAR TECHNO. In this case, it is not necessary to apply the passivation primer of the reinforcement or the concrete primer.
  • If BETOPOX® 93 is used as a bonding primer, PROPAM® REPAR 40 must be applied as long as the bonding primer is fresh, ie within 4 hours of application.
  • For cosmetic repairs of small thickness, use PROPAM® REPAR 5. BETOPOX® 93 is not required for this type of repairs.
  • The curing of PROPAM® REPAR 40, PROPAM® REPAR TECHNO or PROPAM® REPAR 5 is essential for at least 24 hours after application to ensure that the product achieves its intended properties.
  • Use PROPAM® FIX primer to apply single layer mortars of the REVAT® range on the concrete surface.



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