Shrinkage Compensated Fluid Micro-Concrete Incorporating Migrating Corrosion Inhibitor (MCI)
dura.®rep FMC is a cement based non-shrink concrete reinstatement grout, which can be applied by pouring or pumping. The select grading of aggregates and special additives ensures that there is no segregation when pouring, that the thermal coefficient of the cured product matches that of the concrete, that the product has improved strength and is less permeable.
The product is supplied in a ready to use form requiring only the addition of a small amount of water for easy mixing to produce a fluid consistency. This can then be applied 50 mm or thicker into suitable shuttered repair areas.
dura.®rep FMC is particularly used for:
- Reinstatement of large sections of structural concrete with greater than 50 mm thickness.
- Can be applied in excess of 250 mm depending on the nature of the repair and the reinforcing.
- High fluidity required in restricted or congested reinforcing steel elements where compaction or vibration is not possible.
- Shuttered applications for large pours where trowel or hand packed applications are impractical.
- Dams, weirs, bridges, buildings and concrete structures in general.
- Potable water retaining structures.
- Silos and water cooling towers.
- Has shrinkage control in the plastic and hardened phase.
- Exhibits excellent adhesion to concrete substrates without the use of primers.
- The high strength and low permeability provides protection against chloride and carbon dioxide corrosion.
- Alkaline nature will protect the reinforcing steel against corrosion.
- Can be pumped or poured into restricted or congested areas.
- Due to its fluid properties it eliminates honeycombing even without vibration or additional compacting.
- Ease of application only requires the addition of clean water.
- Constant quality/performance (pre-blended).
- Chloride free.
The substrate must be sound, firm and clean, free of oil, grease, loose particles and cement laitance, old layers of paint, or other contaminants. Square cut all edges to be repaired to a minimum depth of 10 mm , perpendicular to the surface followed by the removal of all unsound material. The rest of the repair area must then be broken back to a depth in excess of 50 mm. Never feather edge the product. When using compressed air for cleaning the air must be clean and oil free.
Assess the initial adhesion or the effectiveness of the degreasing by means of pull-off tests. Expose all corroded reinforcing steel and grit blast. A clean metallic finish is required ensuring that all corrosion products are removed, particularly behind the steel. The anchor pattern should be about 40 to 60 microns from peak to valley.
dura.®rep FMC is designed to be cast into and restrained by formwork. This formwork should be well designed and fixed to prevent no loss of material or movement causing poor and unacceptable workmanship. Allowance should be made for the initial drainage of water and the formwork material must be non-absorbent. For easy release the formwork must be treated withdurastrip.
Typical Physical Properties
|Initial set (20°C)||10 hours|
|Final set (20°C)||15 hours|
|Compressive strengths – Mpa ASTM C109|
|Wet density||2 265 kg/m3|
|Water Addition||2,7 litres per 25 kg|
|Yield||12 litres / 25 kg|
|Flow property||975 mm per 20 sec|
Bonding / Priming
Surface saturation is carried out at least four hours prior to placing dura.®rep FMC. This is achieved by filling the prepared formwork with clean water and draining just prior to placing dura.®rep FMC. It is important that all excess water is drained with no free water remaining.
Use epidermix 345 wet-to-dry epoxy as a primer for structural applications where the bond strength must be equal or greater than the parent material. If this option is used, the substrate must remain dry. All exposed reinforcing bars must be primed by applying dura.®rep FMC ZR primer. (See relevant data sheets)
Always ensure that sufficient resources (labour, water, power) are available to provide continuous mix material. A suitable size mixing vessel that will accommodate full bag lots using a pan mixer for forced action mixing is recommended. For small batches a heavy duty industrial drill and spiral paddle stirrer that operates around 400 to 500 r/min can be utilised. In either event tumble type mixers are not permissible. Add approximately 3/4 of the required mixing water and while stirring, slowly add the powder and mix until lump free. Add the remainder of the water and mix for 3 to 4 minutes until the mortar is again completely homogeneous and lump free. It is recommended that the mixed dura.®rep FMC be passed through a suitable coarse screen to identify any unmixed material prio to placing or pumping. For small mixes with a drill and paddle the complete water addition must be used at once. Always add powder to water. The fluid mortar can now be poured into the water tight formwork. NOTE: High-speed mixing entraps an excessive amount of air and therefore should be avoided.
Place approximately 2.0 litres of water in the grout mixer first, then, whilst mixing slowly add the grout and mix for 2 to 3 minutes. Add the balance of the mixing water, 0.70 litres, and mix approximately for 1 minute to obtain the correct consistency ensuring the grout is homogenous and free of lumps. Pour the grout into the pump hopper through a screen with 3 mm openings to separate any lumps and start pumping.
25 kg of dura.®rep FMC powder mixed with 2,7 litres of water yields approximately 12 litres.
dura.®rep FMC can be pumped or poured into the formwork provided. This should be done as a continuous operation and must take place within 30 minutes of mixing. Thereafter the product characteristics will change, affecting its fluidity and expansion properties.
The pump and pipeline must be thoroughly lubricated by pumping a rich cement slurry or mortar through the system, which is then discarded and immediately followed by pumping the product. Always pour or pump from one side only to avoid air entrapment.
Clean tools with water before the mortar hardens. Hardened material can only be removed by mechanical means.
Protection on Completion
The formwork should be left in place for at least 24 hours until the compressive strength of the dura.®rep FMC is 10 MPa or higher. dura.®rep FMC should be cured as soon as the formwork is removed. First soak all exposed areas of the repair with clean water. This is followed by applying, by brush or spray, a suitable curing compound like duracure WBC or as recommended by a.b.e.® Construction Chemicals.
In rapid drying conditions caused by high winds or direct sunlight additional precautions should be included, like sealing with polythene sheeting. This may include damp hessian behind the sheeting to prevent moisture loss. In cold conditions, the repaired area must be protected from freezing. For additional protection properties, dura.®rep FMC is fully compatible with the dura.®cote range of protective coatings when chloride and carbon dioxide screening is essential.
Temperature & Relative Humidity
Surface and ambient temperature must be at least 5°C and rising, ideally between 20°C and 30°C.
A cement based non-shrink concrete reinstatement grout, which can be applied by pouring or pumping.
The micro-concrete will be dura.®rep FMC, a shrinkage compensated, fluid micro-concrete applied in accordance with the recommendations of a.b.e.® Construction Chemicals, including dura.®rep ZR primer for steel and epidermix 345 slow-cure wet-to-dry epoxy adhesive where necessary.
dura.®rep FMC is supplied in 25 kg polyethylene lined paper bags.
Handling & Storage
This product has a shelf life of 12 months if kept in a dry cool place in the original packaging. In more extreme conditions this period might be shortened.
Health & Safety
dura.®rep FMC is alkaline and must not be allowed contact with skin and eyes. Avoid inhalation of dust during mixing by wearing dust masks. The use of gloves, eye protection and dust masks is advised. Immediately wash with water in the event of contact with skin. Splashes into eyes should also be washed immediately with plenty of clean water and medical advice sought thereafter. If swallowed seek medical attention immediately without inducing vomiting.
This data sheet is issued as a guide to the use of the product(s) concerned. Whilst a.b.e.® Construction Chemicals 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.® Construction Chemicals has a wealth of technical and practical experience built up over years in the company’s pursuit of excellence in building and construction technology.