Waterproofing and protecting reinforced concrete against carbonation

RD-ELASTOFLEX, a high-performance water-based elastic and decorative paint for :

- waterprosurfaces while allowing the substrate to breathe
- bridging micro-cracks
- an aesthetic finish that lasts over time

The products you need

The problem

Concrete is a relatively strong material. Good quality concrete is quite capable of resisting acid rain and neutralising the amount of sulphur dioxide and nitrogen oxide it comes into contact with.

However, if the concrete is of poor quality, or subjected to more pollution, or simply aged, various problems can occur that will cause it to crack and water ingress.

In the case of porous or cracked concrete, carbonation is a continuous process which means that sooner or later the steel reinforcement will come into contact with the carbonated area and rust.

The presence of chlorides can accentuate this process as these salts will eventually reach the reinforcement and activate corrosion. Rusting of the rebar will cause the concrete cover to detach from the rebar and to crack!

The solution

RD-Elastoflex

Elastic and breathable waterproofing membrane for the protection of concrete, walls and facades; protects against erosion, carbonation and water infiltration.

Moisture regulating solution to prevent internal condensation and very high elasticity for better crack bridging. Thanks to its high quality resin and pigmentation and its resistance to soiling, RD-Elastoflex keeps the objects it protects in flawless condition for many years.

Recommanded quantity and thickness

RD-Elastoflex : 0,8 kg / m² for 310 µ sec - 75 p² / gallon for 12 mils sec.
The system is applied in a minimum of two coats using a brush, roller or airless sprayer.

Wide choice of colours from the RAL and NCS colour chart. Contact an RD Coatings representative for a custom colour.

Thanks to this solution, rain will not reach the reinforcement, preventing carbonation and curling of the reinforcing bars!

Benefits of the system

This system offers multiple advantages for the contractor and the applicator:

- a certified solution that meets the EN 1504-2 standard
- low VOC (Volatile Organic Compounds) levels
- quick and easy to use solution
- fast drying time and reduced downtime
- extensively tested worldwide
- wide range of colours and very good durability

Our water-based products prevent:

-bringing hazardous products to the site while eliminating the risk of fire or explosion
- nuisances in the vicinity with annoying odours during and after application
- emissions of harmful substances
- losses during and after application

Getting ready

Weather

When working outdoors, avoid starting a job if rain is forecast within 3 hours of application. A minimum of 12°C / 54°F is recommended for comfortable working conditions with higher productivity. Avoid working in direct sunlight, especially in very hot areas, where early morning or late evening work is preferred. Ensure that there is no condensation on the surface before and during application, and during the first hours of drying. In the case of facades, it is sometimes possible to work according to the rotation of the sun, preferring the shaded area in summer and in very hot weather and the sunny area in cooler weather. Ensure that there is no condensation on the surface before and during application, as well as during the first few hours of drying.

Surface preparation

The support must be cleaned, dry and dust free. New masonry must first be brushed with an iron brush to remove the remains of mortar. If there is moss on the support, remove it using a suitable anti-moss product.

- Fill cracks with an acrylic sealant such as RD-Acryl W.
- Use RD-Cement Filler for concrete repairs.
- RD-Mur Fleece should be used where there are active and significant cracks.

Presence of an existing coating

It is essential to check whether the coating still has sufficient adhesion!

Clean previously painted surfaces using a 275 bar - 4000 psi high pressure cleaner with a rotating nozzle. In addition to obtaining a clean surface, this step will ensure that the existing coating still adheres properly.

If there are blisters anywhere, pierce and cut them out, then remove the loose coating. Never paint on a coating that does not adhere well!

On a porous surface

If the substrate to be painted is bare and porous, with occasional residues of old paint adhering well, it is necessary to impregnate carefully and thoroughly with RD-Unifix using a brush or sprayer, so that the substrate has a slightly satin appearance.
This will also ensure a better performance of the following coats and prevent the RD-Elastoflex system from being absorbed into the concrete.

For medium-porous surfaces, another option is to dilute the first coat of RD-Elastoflex with +/- 10% water. This saves one step!

On a smooth surface

Apply a first coat of RD-Elastodeck diluted with 25% water or a coat of RD-Multiprim.

Equipment

RD-Elastoflex can be applied by brush and roller to specific areas or small surfaces, and by airless device to main areas or larger surfaces.

Choose the type of brush according to the size of the objects to be painted.

For roller application you can use a 14 mm polyamide roller.

Specifications for an airless application

RD-Elastoflex: minimum output of 180 bar or 2600 psi and a nozzle size between 0.015 and 0.023 inches.

At the end of the work, clean your equipment with clean water or according to the equipment manufacturer's manual.

The application

The product is ready to use. Stir it mechanically for a few minutes before application. Do not add water except when clearly specified. Check before each application that the surface is free of dust, contamination or condensation.

If preparation or application has been interrupted for more than 3 days without rain or if it is located in a polluted environment, we recommend that the areas to be plastered be washed again or rinsed with a high pressure cleaner, without putting too much pressure, the aim being to remove any dirt.

Advice

To ensure that the correct amount of paint is applied and that the second coat is evenly distributed over the entire surface, we recommend that you choose two different shades to distinguish the first coat from the second.

Application

Apply the first coat of RD-Elastoflex to the entire surface.
Allow the paint to dry for at least 24 hours before applying the second coat. Depending on the weather, this may take more or less time.

Apply a second full coat of RD-Elastoflex to the entire surface the next day.
After 4 hours of drying at 20°C, the coating is dry and rainproof.

The amount applied per m² is important and should be in accordance with the recommendations as it will guarantee the long-term performance of the RD-Elastoflex system. If this has not been achieved, do not hesitate to apply a third coat.

  

Application with RD-Mur Fleece

In the case of active cracks, large cracks, gaps and joints in poor condition, we recommend covering them with RD-Mur Fleece. This is a highly resistant perforated polyester fleece available in various widths and lengths. 

The principle is to place the fleece against the surface and apply the first layer of RD-Elastoflex over it. The paint will pass through the fleece to stick to the surface and trap it in its film as it dries. The next coat is then simply applied on top.

Reinforcing the coating with RD-Mur Fleece ensures that the crack is protected above the crack should it reappear.

Start at the highest point. Apply a small amount of RD-Elastoflex to the surface and hold the fleece roller against the surface to set it in the paint, roll the fleece out gradually +/- 50 cm - 20 inches downwards.

Apply a layer of RD-Elastoflex to the fleece, holding it so that its weight does not lift off the newly applied material, and gradually lower and cut the fleece according to the size of the crack.

Depending on the height and size of the cracks, it is sometimes easier to work in pairs.