durarep repair proven systems and surveys methodology

The repair plan shall be based on findings of the diagnostic survey and other known factors such as the prevailing conditions or limitations under which the repairs are carried out.

Before the work commences the Responsible Engineer specialist contractor and a.b.e.^® representative should meet to discuss recommendations for the application of the repair materials and technical advice and information will beoffered by a.b.e.^®

The repair plan will be subject to the approval of the building owner’s structural specialist. Unless the approved repair plan recommends otherwise the repairs shall be carried out using only the materials specified and skilled workmen under qualified supervision.

The agreed area shall be broken out to remove all contaminated concrete. Where the depth corresponds to the depth of concrete cover and thereby exposes reinforcement, breaking out shall continue to expose the full circumference of the steel and to a further depth of 25 mm or as directed by the Responsible Engineer. Breaking out shall continue along the reinforcement until non-corroded steel is reached and shall continue 50 mm beyond this point or as directed by the Responsible Engineer. Special care shall be exercised to ensure that any reinforcement exposed is not cut or damaged.

It is essential that no chloride contaminated concrete substrate shall be in contact with, or within 10 mm of, the reinforcing bars. In cases where chloride ingress has reached  within 10 mm of the reinforcing bars, the concrete shall be broken out to expose the full circumference of the steel and a further depth of 20-30 mm or as directed by the Responsible Engineer.
Where desalination by electro-chemical means is specified, breaking out chloride contaminated concrete will be limited to areas subject to delamination and/or spalling.

All concrete surfaces to receive repair mortar shall be of a rough scabbled nature. Saw/disc cut edges shall be grit blasted to lightly roughen.

This preparation shall be such as to leave a sound exposed concrete substrate free from dust, loose particles and any deleterious matter.

The following shall apply only to areas to be repaired conventionally:
To form a barrier between the chloride contaminated concrete and the repair mortar, the prepared concrete shall be primed with epidermix® 344 quick set or epidermix® 345 slow set and allowed to cure for 8 – 24 hours. This coating is to be imperforate and should any unfilled voids (blowholes) be apparent, they shall be filled with epidermix® 318 (non-slump) before proceeding.

A second coat of epidermix® 344 quick set or  slow set shall epidermix® 345be applied, blinded with dry, dust free, sharp sand and allowed to harden.

The agreed area shall be broken out to remove all contaminated concrete. Where the depth corresponds to the depth of concrete cover and thereby exposes reinforcement, breaking out shall continue to expose the full circumference of the steel and to a further depth of 25 mm or as directed by the Responsible Engineer. Breaking out shall continue along the reinforcement until non-corroded steel is reached and shall continue 50 mm beyond this point or as directed by the Resposible Engineer.

Special care shall be exercised to ensure that any reinforcement exposed is not cut or damaged.

After breaking out as specified the exposed surface of concrete shall be tested for carbonation as directed by the Responsible Engineer. The test shall be carried out on the freshly exposed concrete or at least within 30 minutes of being exposed. The test shall be carried out on sound, dry and clean air-blown dust free surfaces.

If the concrete substrate still exhibits carbonation in the vicinity of the steel reinforcement, breaking out to remove a further 20 mm shall be carried out and the test repeated. If carbonation is still present the Responsible Engineer shall be notified before proceeding further.

It is essential that no carbonated concrete substrate shall be in contact with, or within 5 mm of, the reinforcing bars. In cases where carbonation has reached within 5 mm of the reinforcing bars, the concrete shall be broken out to expose the full circumference of the steel and a further depth of 20-30 mm or as directed by the Responsible Engineer.

Where desalination by electro-chemical means is specified, breaking out carbonated concrete will be limited to areas subject to delamination and/or spalling.

All concrete surfaces to receive repair mortar shall be of a rough scabbled nature. Saw/disc cut edges shall be grit blasted to lightly roughen.

This preparation shall be such as to leave a sound exposed concrete substrate free from dust, loose particles and any deleterious matter.

All exposed reinforcement shall be cleaned of corrosion products by wet grit blasting or other approved means to achieve a surface finish to comply with a standard of steel cleanliness such as SA2½ (BS7079:Part A1/ISO8501) or as directed by the Responsible Engineer. Special care shall be taken to clean out properly any pitting which may have occurred in the steel bar. Exposed reinforcement in areas to be treated electrochemically shall be cleaned to SA2½ standard.

When the corrosion products have been removed and if directed by the Responsible Engineer, the diameter of the reinforcing bar(s) shall be measured. If considered necessary by the Responsible Engineer the existing reinforcement shall be cut out and replaced and/or additional bars added in accordance with instructions. Any deep pitting of the reinforcing bars shall be brought to the attention of the Responsible Engineer.

Reinforcement damaged during the removal of concrete or the preparation process shall be brought to the attention of the Responsible Engineer and if required, shall be repaired or replaced.

Where the presence of chloride is determined, it is essential that the cleaning process is completed by pressure washing with clean water the total exposed areas of reinforcing steel to ensure the removal of all residual contamination from the pitted surface of steel.

REINFORCEMENT PRIMING

The following shall apply only to areas to be repaired conventionally:

Immediately following preparation and cleaning, the reinforcing steel shall be primed with durarep ZR primer single component epoxy primer complying with the relevant parts of BS4652, 1971 (1979) Specification for Metallic Zinc Rich Priming Paint Type 2. Or depending on the specification for the use of a cementitious primer, use durabond SP – a bonding slurry coat and primer coat with active corrosion inhibitors.

The durarep ZR primer shall be brush applied to the cleaned reinforcement ensuring that all exposed steel is fully coated. Special attention shall be paid to the backs of the steel bars and where steel bars are tied together. It is essential that this coat is continuous with that of any adjacent repaired area where zinc-rich primer has been used. Avoid excessive overpainting onto the concrete and allow to dry.

• EQUIPMENT NEEDED
  20 mm paint brush
  Flat mixing paddle 25 mm wide x 5 mm thick

Repair Areas
The areas to be repaired are to be as shown on the drawings or as indicated by the Responsible Engineer. The areas are to be clearly marked out on site and agreed with the Responsible Engineer before proceeding.

The areas may be adjusted by the Responsible Engineer as work proceeds according to the conditions found.
Propping shall be provided as noted on the drawings or as agreed by the Responsible Engineer.

The surfaces adjacent to and of areas for repair shall be cleaned to remove any dust, unsound material, plaster, oil, paint, grease, corrosion deposits, organic growth, etc.

Within the repair area, the concrete cover to reinforcement links or main bars shall be determined by cover meter.
A small area shall be chiseled out and the concrete cover and the depth of deteriorated concrete confirmed by measurement.

durarep FR mortar, with epidermix® 344 or durabond GP bonding agents, shall be used for vertical or overhead concrete surfaces to be repaired in one single layer passes not more than 30 – 50 mm where 22-25 N/mm² compressive strength and resistance to carbon dioxide and chlorides is required. epidermix® 344 two component, solvent free, polysulphide modified epoxy adhesive shall be applied at 1.7 – 2 m2/L. (Recommended wet film thickness 500 – 600 µm).

The minimum depth for repair shall be 10 mm.

durabond GP acrylic bonding agent shall be applied at 4 – 6 m2/ℓ.

PRIMING CONCRETE
The prepared substrate shall be thoroughly wetted with clean water to totally satisfy absorption and any standing or excess water shall be removed.

The concrete primer shall be durabond GP acrylic emulsion which shall be worked firmly into the damp substrate with a short-bristle brush to achieve a film intimate with the contact area for immediate repair.

Single repair areas larger than 0.5 m² shall be part primed to commence and thereafter progressively in maximum 0.5 m² adjacent bays as application of the repair mortar proceeds.

The repair mortar shall be applied whilst the durabond GP or epidermix® 344 is tacky.

Repairs to concrete subject to permanent immersion shall be primed with epidermix® 345 slow- set or epidermix® 344 quick set which shall be worked firmly into the dry substrate with a short-bristle brush to achieve a film intimate with the contact area for immediate repair.

If the primer dries before the mortar is applied, the area shall be re-primed once.

MIXING REPAIR MORTAR
Before mixing the repair mortar the contractor shall ensure that sufficient and correct areas for reinstatement are prepared and ready to receive repair mortar.

Only mixes using complete bags of durarep FR shall be allowed and part bag mixes not permitted.

The mixing shall be carried out strictly in accordance with current product instructions for use and only with appropriate mixing equipment.

The mixing water shall be potable quality and the carefully measured quantity of water for the required mix shall be placed into the mixing container before the durarep FR.

The durarep FR shall be added to the mixing water and in no circumstances shall more water be added than the maximum volume stated for each bag.

MIXING WARNING
As with other ‘one pack’ repair mortars durarep FR may exhibit satisfactory handling characteristics even though inadequately mixed. This will result in a significantly lower level of performance or possible failure. It is therefore essential that mixing instructions are strictly adhered to with particular emphasis on the quantity of water used and the time of the mixing operation.

APPLICATION OF REPAIR MORTAR
Only fully integrated mixes of durarep FR at the required consistency and workability shall be used.

Immediately following mixing the repair mortar shall be applied by gloved hand or trowel to the prepared and primed surface of the substrate paying particular attention to packing behind and between the reinforcement and thorough compaction overall.

durarep FR shall be applied in accordance with current instructions for use. It may be applied in one operation by building up to the required profile in wet-on-wet layers between 10 – 80 mm vertically and 10 – 50 mm overhead. Thicker sections may be achieved by building up in wet-on-dry layers, where each layer shall be wavy-line scratch keyed with a comb, cured with duracure acrylic, allowed to dry throughout and re-primed at the time of application of subsequent layers.

In hot, humid, coastal situations and in heavy industrial areas ensure that the interval between successive layers is kept to a minimum. This is to prevent possible contamination of the surface of the preceding layer with air-borne contaminants, resulting in possible inter-coat adhesion failure and reduced product performance. In the event that delays are unavoidable, wash down the surface thoroughly with clean water before proceeding with the following coating.
Sagging of the repair mortar is not acceptable and if occurring, all the material of the affected repair shall be completely removed prior to re-priming and refilling in two or more applications of mortar supported by formwork if required.
If formwork is used it shall be pre-treated with a varnish to prevent moisture absorption from the repair mortar. Special care shall be taken to ensure that the positioning of the formwork allows for compaction of and does not result in voids within the repair mortar.

After applying sufficient mortar to achieve a level flush with or slightly proud of the surrounding surface the durarep FR shall be finished by striking off with a straight edge and trowelled/floated depending upon circumstances.
Repair mortar shall not be applied when the ambient or substrate temperature is below 5 °C or above 35 °C nor at an ambient temperature of 5 °C on a falling thermometer.

The applied repair mortar shall always be protected from freezing whilst drying.

CURING
Details of the methods of curing shall be submitted to the Responsible Engineer for approval. Curing techniques shall be instigated immediately following application of repair mortar to any given area. Large areas (0.5 m² at a time) shall be cured as trowelling progresses without waiting for completion of the whole area.

duracure acrylic may be low pressure spray applied as a curing membrane. In fast drying conditions it will be necessary to supplement this with polyethylene sheet taped around its edges. Note: duracure acrylic is compatible with the duracote range of surface coatings and does not require removal prior to application of a duracote material.

Other curing membranes will require removal prior to further surface treatment.

During application and curing all work shall be protected against direct strong sunlight.

durarep GT-MCI mortar with durabond GP or epidermix® 345 slow- set or epidermix® 344 quick set shall be used for concrete surfaces to be repaired in 10 – 30 mm section, small pockets 10 – 100 mm, overhead repairs 10 – 20 mm section, each per layer, where 27-34 N/mm² compressive strength and resistance to carbon dioxide and chlorides is required. The minimum depth for repair shall be 10 mm.

CONCRETE PRIMING
The prepared substrate shall be thoroughly wetted with clean water to totally satisfy absorption and any standing or excess water shall be removed.

CONVENTIONAL CONCRETE REPAIR
The concrete primer shall be durabond GP which shall be worked firmly into the damp substrate with a short-bristle brush to achieve a film intimate with the contact area for immediate repair or epidermix® 345 or epidermix® 344 into a dry substrate.

Single repair areas larger than 0.5 m² shall be part primed to commence and thereafter progressively in maximum 0.5 m² adjacent bays as application of the repair mortar proceeds.

The repair mortar shall be applied whilst the durabond GP, epidermix® 345 or epidermix® 344 is tacky.

Repairs to concrete subject to permanent immersion shall be primed with epidermix® 345 slow-set which shall be worked firmly into the dry substrate with a short-bristle brush to achieve a film intimate with the contact area for immediate repair.

If the primer dries before the mortar is applied, the area shall be re-primed once.

MIXING REPAIR MORTAR
Before mixing the repair mortar the contractor shall ensure that sufficient and correct areas for reinstatement are prepared and ready to receive repair mortar.

Only mixes using complete bags of durarep GT-MCI shall be allowed and part bag mixes not permitted. The mixing shall be carried out strictly in accordance with current product instructions for use and only with appropriate mixing equipment.
The mixing water shall be potable quality and the carefully measured quantity of water for the required mix shall be placed into the mixing container before the durarep GT-MCI.

The durarep GT-MCI shall be added to the mixing water and in no circumstances shall more water be added than the maximum volume stated for each bag.

MIXING WARNING
As with other ‘one pack’ repair mortars durarep GT-MCI may exhibit satisfactory handling characteristics even though inadequately mixed. This will result in a significantly lower level of performance or possible failure. It is therefore essential that mixing instructions are strictly adhered to with particular emphasis on the quantity of water used and the time of the mixing operation.

APPLICATION OF REPAIR MORTAR
Only fully integrated mixes of durarep GT-MCI at the required consistency and workability shall be used.
Immediately following mixing the repair mortar shall be applied by gloved hand or trowel to the prepared and primed surface of the substrate paying particular attention to packing behind and between the reinforcement and thorough compaction overall.

durarep GT-MCI shall be applied in accordance with current instructions for use. Apply in one operation, minimum total thickness is 10 mm, and well compact into repair voids, paying particular attention to compaction around reinforcing steel.
Where the depth of the void is in excess of 30 mm vertically (except for small pockets) or 20 mm overhead, the repair mortar shall be built up in wet-on-dry layers. The repair shall be temporarily finished off at the maximum single application thickness, wavy-line scratch keyed with a comb, cured with duracure acrylic and allowed to harden. It shall then be reprimed at the time of application of the next layer.

In hot, humid, coastal situations and in heavy industrial areas ensure that the interval between successive layers is kept to a minimum. This is to prevent possible contamination of the surface of the preceding layer with air-borne contaminants, resulting in possible inter-coat adhesion failure and reduced product performance. In the event that delays are unavoidable, wash down the surface thoroughly with clean water before proceeding with the following coating.
Sagging of the repair mortar is not acceptable and if occurring all the material of the affected repair shall be completely removed prior to re-priming and refilling in two or more applications of mortar supported by formwork if required.
If formwork is used it shall be pre-treated with a varnish to prevent moisture absorption from the repair mortar. Special care shall be taken to ensure that the positioning of the formwork allows for compaction of and does not result in voids within the repair mortar.

After applying sufficient mortar to achieve a level flush with or slightly proud of the surrounding surface the durarep GT-MCI shall be finished by striking off with a straight edge and trowelled/floated depending upon circumstances.

Repair mortar shall not be applied when the ambient or substrate temperature is below 5 °C or above 35 °C nor at ambient temperatures of 5 °C on a falling thermometer.

The applied repair mortar shall always be protected from freezing whilst drying.

CURING
Details of the methods of curing shall be submitted to the Client’s Representative for approval.

Curing techniques shall be instigated immediately following application of repair mortar to any given area. Large areas (0.5 m² at a time) shall be cured as trowelling progresses without waiting for completion of the whole area.

duracure acrylic may be low pressure spray applied as a curing membrane. In fast drying conditions it will be necessary to supplement this with polyethylene sheet taped around its edges. Note: duracure acrylic is compatible with the duracote range of surface coatings and does not require removal prior to application of a duracote material. Other curing membranes will require removal prior to further surface treatment.

During application and curing all work shall be protected against direct strong sunlight.

durarep FMC high performance, shrinkage compensated micro-concrete suitable for large volume concrete repairs at nominal thicknesses in excess of 50 mm. Supplied as a premix requiring only mixing with water to produce a free flowing material, for placing by hand or pump. The low water requirement ensures fast strength gain and longterm durability.

FORMWORK
Adequate formwork shall be provided in accordance with the relevant codes of practice. It shall be constructed from appropriate materials as agreed with the Responsible Engineer and shall be watertight at all joints between panels, and between formwork and the existing concrete.

The formwork shall be securely fixed to withstand the hydraulic pressures of the fluid micro-concrete without distortion or movement during and subsequent to placement. It may be necessary to divide into suitably sized sections.

Formwork surfaces that are to be in contact with the fluid micro-concrete shall receive one coat of durastrip release agent in accordance with current instructions for use.

The formwork shall include bottom drainage outlets for pre-soaking water, provision for introduction of the microconcrete and air venting as required. The introduction and venting points shall be located so as to avoid any possibility of entrapment of air, etc. Where necessary provision shall be made for controllable venting points to prevent air entrapment and enable the extent of flow of the fluid micro-concrete to be assessed.

In hot, humid, coastal situations and in heavy industrial areas ensure that the interval between priming the reinforcement and erecting the shutter is kept to a minimum. This is to prevent possible contamination of the bond line with airborne contaminants, resulting in possible bond failure with the substrate. In the event that delays are unavoidable, wash down the surface thoroughly with clean water before erecting the formwork.

PRE-SOAKING (unless priming with epidermix® 345)

The formwork shall be inspected by the Responsible Engineer and if approved, the void filled with clean water and kept full. This shall remain for a minimum of 2 hours, then the formwork shall be completely drained and resealed immediately prior to introducing the fluid micro-concrete.

PRIMING CONCRETE HAVING INHERENT CHLORIDE

The following shall apply only to areas to be repaired conventionally:
To form a barrier between the chloride contaminated concrete and the new concrete, the prepared concrete surface shall be primed with epidermix® 344 slow set or epidermix® 345 quick set and allowed to cure for 8 – 24 hours. This coating is to be imperforate and should any unfilled voids (blowholes) be apparent, they shall be filled with epidermix® 318.
A second coat of epidermix® 344 or epidermix® 345 shall be applied, which, depending upon requirements may be (A) immediately followed by the shuttering and pouring of the micro-concrete, or (B) blinded with dry, dust free, sharp sand and allowed to harden before pouring the micro-concrete.

Pre-soaking with water is unnecessary in this case and shall not be permitted.

PRIMING CONCRETE NOT AFFECTED BY CHLORIDES WHERE DELAY FOLLOWING PRIMING IS UNAVOIDABLE
If erection of shuttering, or fixing of steel reinforcement, etc., necessitates priming the prepared concrete before hand, then the primer shall be epidermix® 345 slow set. The epidermix® 345 slow set shall be used in accordance with current instructions for use. It will enable the microconcrete to be placed not before 1 hour and up to 24 hours after the application of the primer.

Pre-soaking with water may be permitted in this case, a minimum of 4 – 6 hours.

MIXING MICRO-CONCRETE
Only mixes using complete bags of durarep FMC shall be allowed and part bag mixes shall not be permitted.
Part 1: durarep FMC powder 25 kg.
Part 2: durarep FMC aggregate 12.5 kg.

The mixing shall be carried out strictly in accordance with current product instructions for use and only appropriate mixing equipment will satisfy.

The mixing water shall be potable quality and the carefully measured quantity of water shall be placed into the mixing container before the durarep FMC.

The durarep FMC shall be added to the mixing water and in no circumstances shall more water be added than the maximum volume specified for each bag.

MIXING WARNING
durarep FMC may exhibit satisfactory handling characteristics even though inadequately mixed. This will result in a significantly lower level of performance or possible failure. It is therefore essential that mixing instructions are strictly adhered to with particular emphasis on the quantity of water used and the time of the mixing operation.

CONCRETING
When assessed in accordance with the flow measurement requirements of DTP BD27/86 the durarep FMC shall flow 750 mm along the test trough within 30 seconds, without segregation or bleeding.

Test cubes may be made at intervals if required by the Responsible Engineer. They shall be made in 100 mm metal mould to BS1881:Part 108. The mould shall be carefully filled to avoid air entrapment.

There shall be no compaction and the top of each cube shall be covered by a metal plate with a weight not less than 0.5 kg. The cubes shall then be cured and tested in accordance with the relevant parts of BS 1881.

Poured material shall be introduced slowly into the formwork. It may be introduced via a funnel, or hopper, at the top of the formwork, unless the configuration of the repair necessitates the use of external pipe-work to reach remote parts of the void. The entry point(s) shall be designed to provide sufficient head of material to ensure total displacement of air.

The placing of the durarep FMC hall be, as far as possible, continuous. The requirements of DTP BD 27/86 permit a maximum 20 minutes between completion of mixing and placing.

Mixing shall be timed so that there is minimal interruption to material placing. If, however, placing is interrupted, this shall be brought immediately to the attention of the Responsible Engineer. The operation may continue while the durarep FMC retains its flow characteristics.

Where fluid durarep FMC is poured in sections, the previously cast edge at the stop end face shall be suitably roughened and cleaned.

durarep FMC hall not be placed when the ambient or ubstrate temperature is below 5 °C or above 35 °C nor at ambient temperatures of 5 °C on a falling thermometer. In cold conditions down to 5 °C the use of warm water, up to 30 °C shall be permitted for pre-soaking and mixing.

FORMWORK REMOVAL
The formwork shall not be removed until the durarep FMC has achieved a compressive strength of at least 10 N/mm² or as directed by the Responsible Engineer.

CURING
Details of the methods of curing shall be submitted to the Responsible Engineer for approval.

Curing techniques shall be instigated immediately following application of repair mortar to any given area. Large areas (0.5 m² at a time) shall be cured as trowelling progresses without waiting for completion of the whole area.

duracure acrylic may be low pressure spray applied as a curing membrane. In fast drying conditions it will be necessary to supplement this with polyethylene sheet taped around its edges. Note duracure acrylic is compatible with the duracote range of surface coatings and does not require removal prior to the application of a duracote material. Other curing membranes will require removal prior to further surface treatment.

Curing shall be instigated immediately after removal of the formwork and continued for at least 3 days.
During application and curing all work shall be protected against direct strong sunlight.

EQUIPMENT NEEDED
100 mm paint brush/roller
back-pack sprayer

Single component polymer modified fairing coat shall be used. It is designed for application to a maximum thickness in one coat of 3 mm. durarep FC may be feather edged.

USE
For fairing following concrete repair; filling blowholes and similar imperfections; providing an ideal background for subsequent surface coatings overall. durarep FC is not designed as a surface finish in its own right.

SURFACE PREPARATION
All surfaces shall be sound, clean and free from dust, plaster, oil, paint, grease, corrosion deposits, laitance, organic growth and any other deleterious substance.

Surfaces shall be cleaned by mechanical means, steam, pressure washing with clean water, grit blasting, or a combination to satisfy. Any remaining dust or loose material should be removed by blowing with oil-free clean compressed air.

MIXING
The mixing shall be carried out strictly in accordance with current product instructions for use and only with appropriate mixing equipment.

MIXING WARNING
As with other ‘one pack’ repair mortars durarep FC may exhibit satisfactory handling characteristics even though inadequately mixed. This will result in a significantly lower level of performance or possible failure.

It is therefore essential that mixing instructions are strictly adhered to with particular emphasis on the quantity of water used and the time of the mixing operation.

APPLICATION
The prepared concrete shall be thoroughly saturated with clean water and maintained in this condition for minimum 30 minutes prior to application of durarep FC.

Using a steel trowel and a scrape-on scrape-off technique, blowholes, imperfections and the like, shall be filled flush to the surrounding surface.

Where the overall surface, or areas thereof, require fairing to produce a smooth, regular surface, further apply the fairing as a render to a maximum thickness of 3 mm. This shall be a separate operation after blow-hole filler has completely dried. Finish with a steel trowel or sponge float to blend to adjacent areas, or according to instructions of the Client’s Representative.

durarep FC shall not be applied when ambient temperature is below 5 °C or 5 °C and falling. Protect durarep FC from rain and from freezing for at least 48 hours after application.

In hot, humid, coastal situations and in heavy industrial areas ensure that the substrate is washed down thoroughly with clean water prior to the application of durarep FC. This is to prevent possible adhesion failure as a result of contamination with air-borne contaminants.

CURING
Provision for curing need only be made where durarep FC is exposed in conditions of very rapid drying.
Where curing is necessary, duracure acrylic shall be applied by low pressure spray to the surface as finishing proceeds.
Only surface coatings like duraflex®, duracote FT or silocoat can be applied over the cured surface.

The surface coating shall be duracote WB water based pigmented elastomeric aliphatic acrylic topcoat having excellent crack bridging properties, available in the a.b.e.® range of colours. Use in conjunction with duracote WB primer penetrating carrier coat incorporating acrylic resin and silane-siloxane forming a reactive hydrophobic primer barrier coat. Apply to the surface not cured with a curing compound.

USE
For application to prepared backgrounds of atmospherically exposed reinforced and pre-cast concrete and masonry where it is required to minimise ingress of carbon dioxide, chlorides and water, whilst permitting moisture vapour transmission from the structure.

SURVEY
Areas recently prepared overall with durarep FC in accordance with a.b.e.® specification will present a surface suitable to directly receive a coating system.

Areas where the previous works have not taken account of the need to prepare the overall surface to receive a coating (small patch repairs with little or no fairing e.g.) shall be the subject of an inspection identifying the background character, nature and surface presentation. Information shall be provided to the Responsible Engineer detailing the areas for surface coating and the degree of preparation proposed together with techniques to be employed. The technical approval of the Responsible Engineer shall be obtained prior to commencement.

Where required by the Responsible Engineer trial areas not exposed in the finished work shall first be treated using selected materials. These trial areas shall be noted on the drawings and shall be carried out using the type of materials, mixing procedures and application techniques that will be used in the contract and shall be approved before the contractor commences the general work. Colour and finish to be agreed by the Responsible Engineer.

SURFACE PREPARATION
All surfaces shall be sound, clean and free from dust, plaster, oil, paint, grease, corrosion deposits, laitance, organic growth and any other deleterious substance.

Surfaces shall be cleaned by mechanical means, steam, pressure washing with clean water, grit blasting, or a combination to satisfy. Any remaining dust or loose material should be removed by blowing with oil-free clean compressed air.
Blowholes, cracks, imperfections and areas of pitting shall be made good with durarep FC in accordance with current product information for use.

In hot, humid, coastal situations and in heavy industrial areas ensure that the interval between successive coatings is kept to a minimum. This is to prevent possible contamination of the surface of the preceding coating with airborne contaminants, resulting in possible inter-coat adhesion failure and reduced coating performance. In the event that delays are unavoidable, wash down the surface thoroughly with clean water before proceeding with the following coating.

APPLICATION
Only the specified areas shall be coated; where protection/masking is required, dependent upon the nature of the coating and its method of application, it shall be provided and installed to the approval of the Responsible Engineer. During application, walkways, plants, joint sealants, asphalt and bitumen painted areas and glass shall be masked and shielding shall be provided to prevent animal contact and to prevent airborne coating materials leaving the immediate area of application.

Thoroughly mix all materials in their original containers and progressively intermix containers of the same colours as the job proceeds.

Surface coating materials shall not be applied in rain or when rain is likely within 6 hours of application.
The primer shall not be applied when ambient and/or background temperatures are below 5 °C or 5 °C and falling. The topcoat shall not be applied when the ambient and/or background temperatures are below 5 °C or 5 °C and falling. Protect all surface coatings materials from frost whilst drying.

PRIMER
Apply duracote WB primer to prepared surfaces at the rate of 2.5 m²/ℓ (per coat) using a portable knapsack-type spray unit. The surface should be flood coated until the substrate has a uniform appearance and sheen. On porous substrates if the surface remains a dull matt appearance further applications of duracote WB primer must be applied until the desired result is achieved. Leave primer to dry for at least 12 hours (@ 20 °C) before the application of duracote WB commences.

TOPCOAT
It is imperative to ensure that the correct application rates and over coating times are adhered to. After the substrate has been primed with duracote WB primer and has dried out completely (min 12 hours @ 20 °C), apply 2 coats of duracote WB to the primed substrate by brush, roller, or suitable spraying equipment at the rate of 2.5 m²/ℓ (total minimum).

Note: A minimum wet film thickness of 200 microns per coat must be achieved. It is essential to ensure that on completion, the duracote WB surface is unbroken and free from pinholes. The first coat should be left to dry for 8 hours.
The finished coating shall be continuous, pin-hole free and have a minimum dry film thickness of 400 microns. Under poor drying conditions at low temperature it is permissible to apply three coats. The colour and finish is to be as agreed with the Responsible Engineer.

duraflex® is a two-component polymer modified cementitious coating, developed for use as an internal coating for potable water retaining structures such as water storage reservoirs and water towers.

The total dry film thickness (DFT) shall be not less than 1.8 mm and shall be capable of providing CO2 diffusion resistance equivalent to not less than 125 mm of 30 MPa concrete cover (Taywood method using Klopfer’s criteria). It shall provide protection against chloride ingress showing no measurable ingress after 400 days immersion under accelerated testing conditions (Taywood Method).

USE
For application to prepared backgrounds of reinforced and pre-cast concrete and masonry where it is required to minimise ingress of chlorides, CO2 and water, whilst permitting moisture vapour transmission from the structure.

SURVEY
Areas recently prepared overall with durarep repair mortars in accordance with a.b.e.® specification will present a surface suitable to directly receive a coating.

Areas where the previous works have not taken account of the need to prepare the overall surface to receive a coating (small patch repairs) shall be the subject of an inspection identifying the background character, nature and surface presentation.
Information shall be provided to the Responsible Engineer detailing the areas for surface coating and the degree of preparation proposed together with techniques to be employed. The technical approval of the Responsible Engineer shall be obtained prior to commencement.

SURFACE PREPARATION
All surfaces which are to receive the coating must be free from oil, grease, wax, dirt or any other form of foreign mtter that might affect adhesion. Good quality concrete surfaces can be cleaned using a high pressure water jet. Poor quality, friable, or contaminated concrete may require grit blasting.

Spalled surfaces or those containing large blow holes, cracks and other such defects should be repaired using a suitable durarep repair mortar.

If the surface contains small blow holes, typically less than 3 mm wide, or cracks no wider than 300 ųm, the coating can be applied directly on to the substrate without the need for a repair mortar.

Only the specified areas shall be coated; where protection/masking is required, dependent upon the method of application, it shall be provided and installed to the approval of the Responsible Engineer.

MIXING
Pour the liquid component from the plastic container into a plastic or metal drum having a volume of at least 20 litres. Gradually add the powder component to the liquid whilst mixing with a propeller agitator attachment on a slow speed drill (400-600 rpm unloaded). Continue mixing, constantly moving the agitator around the drum, until a lump free consistency is achieved. Mixing is continued for a minimum of 3 minutes, stopping at least once to scrape any unmixed powder from the side of the drum into the mixture.

APPLICATION
The prepared substrate shall be thoroughly wetted with clean water to totally satisfy absorption and any standing or excess water shall be removed. In very porous substrates, particularly in hotter climates, saturate the surface, leave for 1 – 2 hours, then saturate again. Ensure excess water is removed before proceeding.

The material shall not be applied when the ambient or substrate temperature is below 5 °C or 5 °C on a falling thermometer. The applied coating shall always be protected from rain and frost whilst drying.

The coating can be applied by soft bristled brush, medium haired roller or steel trowel. A special spray unit has been developed by a.b.e.® for large contracts. Consult your local a.b.e.® representative.

The first coat should be applied at a minimum wet film thickness of 1 mm. Monitor the coating thickness during application at regular intervals using a wet film comb gauge. Care must be taken to check that all blow holes and other imperfections are filled during application. If not, this can be done while the coating is still wet by using a dry sponge. If the coating has dried before these imperfections are found they can be filled using fresh material.

Allow to cure for a minimum of 4 hours @ 20 ºC/50 % RH. This time can be reduced substantially in hotter climates.
All the mixed material should be used within 45 minutes of mixing. In hot, humid, coastal situations and in heavy industrial areas ensure that the interval between successive coatings is kept to a minimum. This is to prevent possible contamination of the surface of the preceding coating with air-borne contaminants, resulting in possible inter-coat adhesion failure and reduced coating performance. In the event that delays are unavoidable, wash down the surface thoroughly with clean water before proceeding with the following coating.

The second coat should also be applied at a minimum wet film thickness of 1 mm. Monitor the coating thickness during application at regular intervals using a wet film comb gauge. Pre-dampening of the surface is not necessary when applying the second coat.

FINISHING
To produce a smooth finish or to repair film defects use either a steel trowel, caulking tool or hard sponge. This should be done immediately after application, otherwise the coating may drag or tear.

When using a hard sponge it should be dry or very slightly damp. A wet sponge should not be used as this will cause polymer to come to the surface of the coating that causes an unsightly white streaky effect.

CURING
Under normal conditions of application, no curing is required.

PRODUCTS REQUIRED
abe® super brush cleaner
durabond GP
duracote WB
duracote WB primer
duraflex®
durarep FC
durarep FMC
durarep FR
durarep GT MCI
durarep ZR primer
durabond SP
epidermix® 344
epidermix® 345
epidermix® 318
duracure acrylic

EQUIPMENT NEEDED
Heavy duty Festo mixer with helical mixing head
Steel trowel or suitable short bristled brush
Spatula

epidermix products should be removed from tools, equipment and mixers with abe^® super brush cleaner immediately after use. Hardened material can only be removed mechanically.

• abe^®super brush cleaner
• abe.^®cote 352
• dura.^®bond GP
• dura.^®cote WB
• dura.^®cote WB primer
• dura.^®rep FMC
• epidermix 345
• epidermix 505

• 150 mm paint brushes
• Flat steel mixing paddles 25 mm x 5 mm
• Heavy duty Festo mixer with a helical mixing head
• Pan Mixer
• Short nap roller
• Steel Floats
• Steel Trowel
• Suitable 25 litre mixing bucket

This data sheet is issued as a guide to the use of the product(s) concerned. Whilst a.b.e.^® Saint-Gobain endeavors to ensure that any advice, recommendation, specification or information is accurate and correct, the company cannot – because a.b.e.^® has no direct or continuous control over where and how a.b.e.^® products are applied – accept any liability either directly or indirectly arising from the use of a.b.e.^® products, whether or not in accordance with any advice, specification, recommendation, or information given by the company.

Where other products are to be used in conjunction with this material, the relevant technical data sheets should be consulted to determine total requirements. a.b.e.^® Saint-Gobain has a wealth of technical and practical experience built up over years in the company’s pursuit of excellence in building and construction technology.