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Technical Dayta Sheet Compedium

CONTENTS CONCRETE REPAIR CORROSION CONTROL GROUTS & ANCHORS PROTECTIVE COATINGS INDUSTRIAL FLOORING SURFACE TREATMENTS JOINT SEALANTS CONCRETE JOINTING JOINT FILLERS WATERPROOFING WATERSTOPS ROOFING TIMBER FLOORING ALPHABETICAL INDEX and vertical build up of the Renderoc HB25 mortar may be difficult. Scrubbing by hand a thin layer of the Renderoc into the tacky primer will assist adhesion and also minimise the chance of the primer drying out. If the Nitobond HAR primer dries before the application of the Renderoc, the area must be re-primed before proceeding. In exceptional circumstances, e.g. where a substrate/repair barrier is required or where the substrate is wet or likely to remain permanently damp, Nitobond EP bonding aid should be used. Contact your local Parchem sales office for further information. Note: Nitobond HAR primer is generally not required when wet spraying Renderoc HB25. Refer to the separate information document “Wet Spraying Renderoc mortars” available from Parchem branches. Mixing Care should be taken to ensure that Renderoc HB25 is thoroughly mixed. A forced-action mixer is essential. Mixing in a suitably sized drum using an appropriate spiral paddle such the Protool HS2 140 x 600 M14 Helical mixing paddle (product code: TT-614217) or equivalent at a slow speed (400/500 rpm) using a heavy-duty mixer, 1500W such as Protool MXP 1602 E (product code: TT-621941) or equivalent is acceptable for the occasional one-bag mix. Free-fall mixers must not be used. Mixing of part bags should never be attempted. For normal applications, place 2.6 - 2.8 litres of drinking quality water into the mixer and, with the machine in operation, add one full 15 kg bag of Renderoc HB25 and mix for 3 - 5 minutes until fully homogeneous. Note that the powder must always be added to the water. Initially add 2.6 litres of water, mix the product for a minimum 3 minutes to allow the polymers in the mix to activate; then make any necessary water adjustments after this time up to the maximum 2.8 litres. Application Exposed steel reinforcing bars should be firmly secured to avoid movement during the application process as this will affect mortar compaction, build and bond. Apply the mixed Renderoc HB25 to the prepared substrate by gloved hand or trowel. Thoroughly compact the mortar on to the primed substrate and around the exposed reinforcement. Renderoc HB25 can be applied in sections up to 80 mm thickness in vertical locations and up to 60 mm thickness in overhead locations in a single application and without the use of formwork. Thicker sections should be built-up in layers but are sometimes possible in a single application dependent on the actual configuration of the repair area and the volume of exposed reinforcing steel. Thicker applications can always be achieved by spray application - see below. If sagging occurs during application, the Renderoc HB25 should be completely removed and reapplied at a reduced thickness on to the correctly reprimed substrate. Note: the minimum applied thickness of Renderoc HB25 is 10 mm. Build-up Additional build-up can be achieved by application of multiple layers. The final thickness is dependent on the material consistency and substrate profile. The surface of the intermediate layers should be scratchkeyed and cured with Nitobond AR*. Repriming with Nitobond HAR and a further application of Renderoc HB25 may proceed as soon as this layer has set. Wet spray application Renderoc HB25 can be quickly and efficiently applied by the wet spray technique. In circumstances where large areas of repair are required, the rapid placement and higher build attainable by this method offer economic advantages over hand-trowelling. The resultant repair also offers a generally more dense compound with enhanced mortar/substrate bond characteristics. For further details on the wet spray technique, including selection of spraying machines and nozzles, consult the document “Wet Spraying Renderoc mortars” or contact your local Parchem sales office. Finishing Renderoc HB25 is finished by striking off with a straight edge and closing with a steel trowel. Wooden or plastic floats, or damp sponges may be used to achieve desired surface texture. The completed surface should not be overworked. Allow the applied Renderoc to stiffen before attempting to finish off - this will minimise slumping. After spray application, the mortar may need to be ‘cut back’ to the required profile using a steel trowel and then finished with damp sponges as described above. Low temperature working In cold conditions down to 5°C, the use of warm water (up to 30°C) is advisable to accelerate strength development. Normal precautions for winter working with cementitious materials should then be adopted. The material should not be applied when the substrate and/or air temperature is 5°C and falling. At 5°C static temperature or at 5°C and rising, the application may proceed. High temperature working At ambient temperatures above 35°C, the material should be stored in the shade and cool water used for mixing. Curing Renderoc HB25 is a cement-based repair mortar. In common with all cementitious materials, it must be cured immediately after finishing in accordance with good concrete practice. The use of Nitobond AR or Concure A99, sprayed on to the surface of the finished mortar in a continuous film, is recommended. Large areas should be cured as trowelling Page 3 11 Fosroc® Renderoc HB25


Technical Dayta Sheet Compedium
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