weber.cemHB40 

weber.cem HB40 is a single-component, polymer-modified, high-build cementitious mortar, designed for structural concrete repairs. It requires only the addition of clean water to produce a lightweight, low-permeability, high-strength mortar for both soffit and vertical repair situations. The mortar is suitable for repairs to bridges and other structures as specified by the Department of Transport.

This product has been formulated to comply with the requirements of BS EN 1504-3:R3 mortar.

• Lightweight, low-density structural repair mortar which allows speedier completion of work
• High-build properties - up to 100 mm vertically and 75mm in a soffit repair, without formwork
• Compatibility with concrete greater than 30 N/mm2
• Unique shrinkage compensation system provides long-term dimensional stability. Less than 0.02% shrinkage at 28 days
• Contains fibres and spray dried acrylic polymer
• Low permeability to water, carbon dioxide and chlorides
• Easy to apply, with excellent application properties
• Complies with Department of Transport Departmental Standard BD 27/86
• Agrément approved as part of the weber.cem Concrete Repair System

Concrete substrates
Concrete substrates must be adequately prepared by use of scabbling, grit blasting, needle gunning or other means, as appropriate. Oil and grease must be removed by steam cleaning together with suitable detergent. Any contaminated concrete must be removed. All damaged concrete should be cut back to a sound surface and at least 15 mm behind any exposed reinforcement.

New concrete must be at least 14 days old.

Thoroughly saturate the concrete but remove excess water.

Steel substrates
These should be grit blasted to Swedish Standard SA 21/2 equivalent to BS 7079-A1 and degreased immediately prior to application. Where corrosion is absent, wire brushing to a clean, bright surface may be adequate. Care must be taken not to polish the rust. Apply a protective coating of weber.cem keycoat as described below to act as a holding primer.

Note: Preparation of both concrete and steel must achieve a clean, sound, roughened surface.

Mixing of bonding slurry
Mix 2 volumes of weber.cem keycoat powder to 1 volume of clean water. Mix vigorously to a brushable, slurry consistency.

For detailed application instructions, see separate weber.cem keycoat data sheet.

Mixing weber.cem HB40
A low-shear, forced-action mixer must be used, e.g. Mixal Mixer or Creteangle. Hand mixing the mortar is not recommended.

Mix for 2 minutes from adding the powder to the water.

Over mixing will entrain air and reduce compressive strength. Do not overmix.

Water addition is 2.4 to 2.7 litres of clean water per 20 kg bag. Start at 2.4 litres and adjust as required upwards to 2.7 litres.

Do not add more than 2.7 litres of water.

Priming of steel reinforcement
Apply one full, unbroken coat of weber.cem keycoat, ensuring the back of the cleaned reinforcing bars are coated.

Priming of concrete substrate

Ensuring the prepared concrete substrate is saturated but surface damp, use a stiff brush to scrub the slurry well into the surface.

Apply the mortar to the substrate whilst the bonding slurry is still tacky and compact well into place, ensuring no air is trapped.

The minimum application thickness is 10 mm. Where very thick sections are required, multiple applications may be necessary. Intermediate surfaces should be scratched to give a good mechanical key.

Successive applications require the use of weber.cem keycoat.

Finishing
If subsequent materials or coatings are to be applied, finish with a wooden or plastic float or sponge to present a lightly textured surface. Otherwise, finish with a steel float for a tightly closed surface.

Curing

Unless a coating or other system is to be applied to the surface, cure immediately after finishing with weber.tec ritecure.

Before application of a coating or a levelling mortar, cure the repairs by covering with closely-fitting polyethylene sheeting or use weber.tec latex as an intermediate curing membrane sprayed onto the repaired surfaces in a continuous film.

weber.tec HB40 can be overcoated by the levelling mortar weber.cem fairing coat or one of the anti-carbonation coatings in the weber.cote range. Overcoating times are dependent on weather conditions.

When cured, weber.cem HB40, and weber.cem keycoat are stable to freeze/thaw conditions but, following good concreting practice, they should not be applied in freezing weather or onto frozen surfaces or at temperatures below 5°C.

weber.cem HB40 yields Approximately 16.0 litres per 20 kg bag, i.e. 63 bags per m3 or 1.6 m2 per bag at 10 mm thickness.

weber.cem keycoat Approximately 1 kg per 1 m2.

When stored unopened in a dry place at temperatures above 5°C, shelf life is 12 months from date of manufacture.

Contains cement (Contains chromium (VI). May produce an allergic reaction). Harmful by inhalation. Irritating to eyes and skin. Keep out of the reach of children. In case of contact with eyes, rinse immediately with plenty of water and seek medical help. After contact with skin, wash immediately with plenty of soap and water. Wear suitable protective clothing, gloves and eye/face protection.

For further information please refer to the Weber Safe Handling Guide.

weber's Customer Services Department has a team of experienced advisors available to provide on-site advice both at the specification stage and during application. Detailed specifications can be provided for specific projects or more general works. Site visits and on-site demonstrations can be arranged on request.

Technical helpline
Tel: (01525) 722110
Fax: (01525) 718988

weber products are distributed throughout the UK through selected stockists and distributors. For UK sales enquiries and overseas projects, contact Weber's Sales office.

Sales office
Tel: (01525) 722100
Fax: (01525) 718988