Products with MCI to Repair Concrete Pathologies

What are Concrete Pathologies? In this article, we will explain the most frequent ones.

Concrete pathologies are problems or defects that can occur in concrete structures, whether they are buildings, bridges, pavements or other engineering works. They can be caused by various factors derived from the quality of the materials used, the design, the execution of the work or unfavourable environmental conditions and agents, such as excessive humidity or temperature.

One of the most common pathologies in concrete is carbonation. This phenomenon occurs when carbon dioxide from the air in the presence of moisture reacts inside the concrete, causing a decrease in the pH of the concrete, leaving the reinforcement unprotected against corrosion.

Reinforced concrete structures deteriorate due to attacks on the concrete itself or corrosion of its reinforcement. The presence of pollutants, such as atmospheric carbon dioxide and chlorides, cause this deterioration, as they promote the oxidation of the steel.

Another common pathology is the appearance of cracks and fissures in reinforced concrete. These cracks can be due to different reasons, such as shrinkage of the concrete during setting, temperature changes, overloading or differential settlement of the ground. Cracks can compromise the strength and durability of the concrete, allowing water and aggressive agents to enter, which accelerates the corrosion of the reinforcement and weakens the structure.

To prevent and correct them, proper quality control in concrete production is essential, as well as careful design and execution of the works. In addition, regular monitoring and maintenance of the structures is crucial to detect any pathology in time, ensuring the safety and durability of the works.

Thus, it is essential to choose them in such a way that they can correctly protect against the aggressor agent, of course, after an analysis and diagnosis of the problem we want to tackle.

To this end, protection of the concrete reinforcement is essential. In many cases, concrete infrastructures have insufficiently coated elements or high porosity, which makes the reinforcement more vulnerable to corrosion.

In this context, modern reinforced concrete protection systems using Migratory Corrosion Inhibitors – based on amino-alcohols and aminocarboxylates – allow high levels of protection to be achieved.

These Inhibitors move as a liquid through the concrete matrix by capillary action and migrate – due to their vapour phase – through the porous structure of the concrete.

Migratory inhibitors are classified as mixed inhibitors, which means that they affect both the anodic and cathodic portions of a corrosion cell. They thus significantly increase the chloride threshold necessary for attack, reduce the rate of diffusion and, in addition, reduce the corrosion rate of the armour once corrosion has started.

How to prevent concrete pathologies? List of tips

We give you some very general lines of action to prevent possible pathologies that may arise in the case of concrete.

Appropriate design:

Ensure that you have an appropriate structural and concrete mix design for the specific project, considering the loads, environmental exposure and strength requirements.

Selection of quality materials:

Uses high quality building materials, including cement, aggregates and admixtures. Verify that they comply with appropriate norms and standards.

Control of the water-cement ratio:

Maintain a proper ratio of water to cement to achieve a compact and strong mix. Avoid excess water, as it can weaken the strength and durability of the concrete.

Care in the mixing process:

Make sure that all concrete components are properly mixed, avoiding segregation and ensuring an even distribution of materials.

Adequate curing:

Provides a proper curing process to allow the concrete to reach its optimum strength. It uses techniques such as constant watering, the application of curing membranes or the use of appropriate chemical compounds.

Humidity control:

Prevents unwanted water from entering the concrete through proper drainage design and proper waterproofing of exposed surfaces.

Protection against aggressive agents:

Consider the exposure of concrete to agents such as chloride, sulphate or other corrosive chemicals, and take measures to protect it through coatings, sealants or other protective systems.

Regular maintenance:

It carries out regular inspections to detect possible pathologies, such as cracks or corrosion, at an early stage and takes the necessary corrective measures in a timely manner.

Specialised professionals:

Make sure that you have qualified and experienced personnel in the execution and quality control of the concrete, following good construction practices.

Regulations and standards:

Familiarise yourself with local and international regulations and standards related to concrete, and ensure that you comply with them at all stages of the project.

By following these tips, you will be taking preventive measures to avoid pathologies and promote the durability of concrete in your construction projects.

Products with MCI to Repair Concrete Pathologies

As an expert in innovative solutions for healthy construction, we have launched a new generation of mortars with MCI® migratory corrosion inhibitors, a range of products with the most advanced technology to boost the maximum durability of reinforced concrete.

With this generation of mortars, a pioneer in the national market, Molins consolidates its commitment to innovation and sustainability, axes that will allow the useful life of concrete structures to be extended to the maximum.

It’s about making repairs to structures more resistant to corrosion. And greater durability means fewer repairs, greater structural integrity and a longer service life, which also translates into greater sustainability and a reduced carbon footprint.

As mentioned above, reinforced concrete structures deteriorate due to attacks on the concrete itself or corrosion of its reinforcement. The presence of pollutants, such as atmospheric carbon dioxide and chlorides, cause this deterioration, as they favour the oxidation of the steel.

In particular, these two phenomena – carbonation of the concrete and chloride attack – make continuous maintenance work essential throughout the life of the structure and therefore an additional cost.

Our products -which comply with the requirements of the EN 1504-3 class R4, EN 1504-2 and EN 1504-7 standards-, have taken part in various accelerated corrosion tests which have accredited how PROPAM® REPAR TECHNO 40 MCI and PROPAM® REPAR TECHNO FLUID MCI mortars delay the initiation of corrosion by carbonation by at least six times compared to traditional mortars and improve the critical concentration of chlorides to values much higher than those normally found in traditional mortars or concrete.

Repairing Concrete Pathologies with MCI Products

At Molins we use the most advanced technology in Migratory Corrosion Inhibition (MCI®), based on which we have developed the most advanced technical mortars on the market, providing a solution of maximum durability in the repairs carried out.

• Structural concrete repair mortar Class R4.
• Coating (C) for penetration protection (PI), moisture control (MC) and increased resistivity by limiting moisture content (IR).
• Coating for the protection of reinforcement against corrosion.
• Active protection by MCI® Migratory Inhibitors.

By means of different technical tests, in which the mortar is subjected to carbonation and chloride attack processes, at Molins we have been able to confirm the improvement achieved and the excellent protective behaviour of the mortars.

Thus, PROPAM® REPAR TECNO 40 MCI and PROPAM® REPAR TECHNO FLUID MCI, manufactured with migratory corrosion inhibitors (MCI®), have the capacity to increase the threshold concentration at which chloride ion corrosion usually occurs and to delay the onset of corrosion, reducing the corrosion rate (loss of section of the

armour).

It also acts on carbonation corrosion phenomena, delaying the onset of carbonation and also slowing down its speed once it has started.

Tips for repairing with Molins MCI products

We can act preventively or curatively with our MCI products.

By using liquid inhibitors such as CORTECMCI 2020, we can protect newly manufactured structures without pathologies, considerably increasing the durability of the structure, thanks to its ability to penetrate into the concrete, more than 7 cm in 30 days. In addition, it does not prevent vapour diffusion through the concrete.

In the case of curative concrete repairs, the combination of CORTEC MCI 2020 on the prepared structure prior to repair will allow us to act on the innermost areas of the concrete and reach the innermost reinforcements, to subsequently repair the exposed reinforcements with a high-performance mortar, PROPAM REPAR TECHNO 40 MCI, which incorporates corrosion inhibitors.

The repair process with PROPAM REPAR TECHNO 40 MCI does not require any additional action to those normally carried out.

Do you want to know more? We leave you here, in this link, all the solutions with corrosion inhibitors proposed by Molins.

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