Quick Links - Click To Jump To Section:

   
• Features & Benefits
• Application Notes
• Limitations

Features & Benefits

• Free-flowing, shrinkage compensated microconcrete
• Based on Portland cement, graded aggregates and additives which impart controlled expansion in both the plastic and hardened states while minimising water demand
• Maximum compatibility with concrete of compressive strength 30 - 60 N/mm²
• plastic and hardened states - allows high application thicknesses
• Low alkali content minimises risk of alkali-silica reaction
• Exceptional bond to concrete substrates without independent primer
• Suitable for placement by pumping or pouring techniques into restricted locations
• Self-compacting nature eliminates honeycombing and displaces air without vibration
• High strength and low permeability provide maximum protection against carbon dioxide and chlorides
• Supplied as a ready to use blend of dry powders pre-bagged to overcome site-batched variations — only the site addition of clean water is required
• Contains no chloride admixtures

Uses

• Formulated for use on highways projects
• Designed for large volume repairs typically in excess of 25mm deep
• Can be applied in sections generally up to 200mm thick although greater thicknesses may be achievable dependent on the configuration of the repair location and the volume of exposed reinforcing steel
• Suitable for repair methods 3.2, 4.4, 7.1, 7.2 as defined by BS EN 1504-3
• Conforms to the requirements of the UK Highways Agency Design Manual for Roads and Bridges (BD27/86, Clause 4) ‘Materials for the Repair of Concrete Highway Structures'
• Formulated to comply with the requirements of the Specification for Highway Works, Clause 1704.5 Control of Alkali-Silica Reaction

Application Notes

• Priming of the steel reinforcement is not normally necessary unless it is to remain exposed in an environment likely to cause corrosion after preparation. When required apply one full coat of Nitoprime Zincrich Plus and allow to dry before continuing
• Several hours prior to placing, the prepared concrete substrates should be saturated by filling the prepared formwork with clean water. In exceptional circumstances, e.g. where a substrate/repair barrier is required, Nitobond EP bonding aid should be used to prime the substrate
• A forced-action mixer is essential. Mixing in a suitably sized drum using an approved MR3 mixing paddle with a slow speed (400/500 rpm) heavy-duty drill is acceptable
• Pour the mixed material into the prepared formwork in a continuous fashion, ensuring any trapped air at the top of the formwork is released
• Can alternatively be pumped in place using a mortar pump plastering machine (must be capable of handling 4 - 6mm aggregate)
• In cold conditions down to 3°C, the use of warm mixing water (up to 30°C) is advisable to accelerate strength development. At ambient temperatures above 35°C, the material should be stored in the shade and cool water used for mixing
• In common with all cementitious materials, Renderoc LA55 must be cured immediately after the formwork is stripped in accordance with good concrete practice
• Immediately after striking the formwork, all exposed faces of the repair should be thoroughly soaked with clean water and then sprayed with a liquid curing membrane such as Concure WB, Nitobond AR or Fosroc Cure B
• If the repair is to be overcoated, use Nitobond AR to cure the repair
• Dekguard products may be applied over the repair area without prior removal of the Nitobond AR curing membrane. All traces of form-release oils and curing membranes (other than Nitobond AR) must be removed prior to the application of Dekguard products
• Should be removed from tools, equipment and mixers with clean water immediately after use. Cured material can only be removed mechanically.
• Yield: Approx. 12.0 litres / 25 kg bag

Limitations

• Should not be used when the temperature is below 3°C and falling
• Free-fall mixers must not be used. Mixing of part bags should never be attempted
• The product should not be used to reinstate horizontal areas where the surface would remain unrestrained during cure
• Should not be exposed to moving water during application
• As with other ‘one pack’ repair mortars, Renderoc LA55 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