Concrete Repair

Concrete preparation

The surface of the concrete to be repaired should be sound, clean and uncontaminated. The decayed or damaged area to be repaired should be marked with a marker. Cut the marked area to a depth of at least 10mm using a hand held concrete saw or disc grinder to avoid feather edging and to provide a square edge. Break out or chip the complete repair area down to sound base using sharp tools or chipping hammer.

Oil and grease deposits should be removed by stiff brushing, detergent scrubbing with a heavy duty cleaner/degreaser or steam cleaning.

Steel preparation

Any corroded steel in the repair area must be fully exposed. All exposed reinforcement shall be cleaned of corrosion products by wet grit blasting or other approved means to achieve a clean and bright finish.

In case that reinforcing bars section is reduced due to oxidization, integrate them with additional bar reinforcement.

Priming

Steel Priming

The cleaned steel should be coated within 3 hours. Apply one coat of BETOFER, a corrosion proof cementitious based primer or EPOZINC, a two component Zinc rich EPOXY PRIMER, continuously with brush onto the cleaned bar reinforcement ensuring that the whole steel surface area is completely covered. Allow to dry before continuing.

Concrete Priming

If the concrete deterioration is due to Chloride attack, it is recommended to use EPORIPRESA, an epoxy bonding agent. It will cure to form a barrier against Chloride ions. However if the cause is Carbonation, dampen the surface with clean water (avoiding free standing water) and apply thin coat of AR LATEX RIPRESA, an Acrylic bonding agent.

BETOCEM HR must be applied before the bonding agent dries while it’s still tacky to achieve a better bond between the fresh and cured section.

Mixing

For mixing process, a slow speed drill (200 - 300rpm) fitted with a suitable paddle is recommended. Place 4.0-4.5 liters of cold clean water in the mixing bucket. With the drill in operation, add the entire content of the 25 kg bag of BETOCEM HR while mixing continuously till a uniform lump free consistency mix is achieved. Powder must always be added to water.

Allow the obtained mix to stand for about 3 minutes and then remix before application. Under no circumstances should partial mixing be considered.

Application

Apply the product manually with a trowel or spatula with full compaction, to primed substrate while it is still tacky.

The minimum applicable coat thickness is 10mm and the maximum shall be 35mm for vertical and 25mm for overhead sections. For small horizontal sections, the applicable thickness shall be from 10mm up to 100mm Application thickness is dependent on repair size and granulometry. High build applications can be achieved through temporary formwork.

If the application of the second coat is necessary the previous layer should be cross hatched and allowed to take up its initial set before applying the next coat. Use trowel or sponge for the finishing touch.

Curing

The repaired area shall be cured in accordance with good concrete curing practice and protected from drying winds, sun or excessive heat. Curing shall be done with non-degradable curing compound BETOCURE AR. Alternatively; a wet hessian cloth covered with polyethylene sheet can also be employed. Curing should begin as soon as final finish is achieved. In fast drying conditions, supplementary curing with Polythene Sheets must be used.

Cleaning

BETOCEM HR should be removed from tools and equipment and mixers with clean water immediately after use. Cured material should be removed mechanically.

Equipment used for applying EPORIPRESA, the epoxy bonding agent should be cleaned with SOLVENTE 10.

Recommendations

• Do not apply the product at a temperature less than +5ºC
• During the peak temperature of the day in the summer season, working area should be covered if work to be executed externally. Use Cold water to mix the product
• In warm weather, store the material in cool place. Make sure to use cool water to keep the mixed mortar temperature below 30 ºC.