About this Product
webercem spray RS is a ready-to-use, polymer-modified, dry-sprayed concrete able to achieve early set, ideal for permanent concrete repairs where time constraints demand early strength gain. The material contains inert limestone aggregates, dust suppressants and accelerators. The formulation is designed for the dry spray process method of application with reduced rebound and maximum applied thickness.
Conforms with BS EN 1504-3 as a Class R4 repair product.
Features and Benefits
- Rapid setting allows work to continue in tidal zones
- Prevents wash out from tidal action or flowing water
- Economical with low rebound than conventional spray concretes
- High-build - up to 100 mm thickness can be applied in one pass to vertical faces
- Good adhesion to concrete substrates
- Non reactive aggregate complying with clause 1704
- Total chloride ion content does not exceed 0.05% of the weight of cement. No calcium chloride or admixtures containing chloride salts are used
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.
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.
Tel: (01525) 722100
Fax: (01525) 718988
Material Safety Datasheet
Declaration of Performance (DoP)
Preparation & Application
As with all concrete repairs, it is essential to apply the material to a clean, sound surface which is free from all grease, oil, dust and loose material.
Concrete substrates must be adequately prepared by suitable mechanical method such as light scabbling, grit blasting, water jetting or needle gunning. Concrete must be carefully exposed to give a clean, freshly-exposed surface. The outer limits of the repair should be cut square to avoid feather edges.
Old surfaces contaminated with oil or grease must be cleaned with a suitable detergent. Care must be taken that the contaminants are removed and not simply spread over a wider area.
The designer may require the sprayed concrete to be reinforced with mesh or bars.
Any reinforcement shall be fixed in accordance with the recommendations outlined in the Sprayed Concrete Association, SCA-Design and Specification and Concrete Society Technical Report 15.
In most cases, no additional mesh reinforcement is required in repairs where existing rebar exists or where thin overlays are applied (i.e. less than 25 mm, see SCA recommendations).
Soak the concrete thoroughly and allow any surplus water to drain off.
Steel surfaces, including exposed reinforcement, should be free of loose rust and grease. Ideally they should be grit blasted to a uniform grey metal finish to achieve first quality to BS 7079-A1.
Guidelines on the method of working are detailed in the Spray Concrete Association, SCA, guidelines and the EFNARC Specification for Sprayed Concrete - Guidelines for specifiers and contractors.
webercem spray RS should be emptied from the bags directly into the hopper of the spray machine.
The equipment should be balanced so as to produce a steady stream of material with minimal pulsing. The amount of water added at the nozzle will be controlled by the nozzleman:
- too low an addition will increase rebound and dust emission;
- too wet a mix will resulting in slump.
The correct amount of water can be judged by the appearance of the sprayed concrete. Avoid any glossy finish.
In the case of a long delay between applied coats of spray concrete, the surface of the newly applied spray concrete be water jetted to remove any laitance, weak layers or surface loose material before re-spraying.
The surface should be allowed to drain before proceeding with the next coat.
This material can be applied down to 10mm thickness but the recommended thickness for protection of the steel is 25 mm.
This material will set quickly and any finishing must take place within 15 minutes of application.
We recommend an 'as sprayed' finish is used with webercem spray RS. Curing
This material must be cured correctly and for as long as possible in accordance with guidelines set by EFNARC and SCA.
Cure immediately with polythene sheeting and/or wet hessian for a minimum of 3 days.
In general, sprayed concrete should be cured as above. However, where the ambient temperature exceeds 25°C, or in exposed conditions where air movement can cause a rapid drying out of the surface, then the sprayed surface must be protected by wet hessian or a fog spray system. In these conditions no surface should be exposed for longer than one hour.
Protect from frost.
Packaging, Health & Safety
webercem spray RS is supplied in 25 kg polylined paper bags.
Coverage / Yield
Approximately 11.5 litres per 25 kg bag. An allowance must be made for rebound and wastage.
Storage and Shelf Life
When stored unopened in a dry place at temperatures above 5°C, shelf life is 6 months from date of manufacture.
Health and Safety
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 request the Material Safety Data Sheet for this product.
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