Application Guidelines

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RBI Grade-81 is applied like cement, lime, flyash, etc, but it does not have the setting time constraints of these stabilisers. Although RBI Grade-81 is suitable for immediate traffic use after full compaction at optimum moisture, it may be re-worked for a much longer period than cement.

RBI Grade-81 is effectively a bitumen primed stabilised pavement with the priming to the full depth of the stabilisation. Bitumen sealing costs are reduced, the seal is far more reliable, and it cannot be removed by excess heavy traffic stresses or turning stresses. We believe that a seal over RBI Grade-81 provides probably the most reliable pavement seal available.

Handling requirements for RBI Grade-81 are similar to those required for cement and lime, and Materials Safety Data will be supplied on request.

Because RBI Grade-81 may be worked without restrictive time constraints, it is suitable for direct application to the road base material in situ, using stabilising machinery. Small applications can be done with tractors, rotary hoes, bobcats, etc. as well as blade mixing with graders. It may also be used to make pre-mix stabilised material in Pug Mills and Agitators, or by heap mixing with front-end loaders.


A base stabilised with RBI Grade-81 may normally be used unsealed under traffic, and it will be hard wearing for days (sometimes weeks) before sealing with bitumen. Water carts and graders etc. should not normally be needed.

Site Preparation (for direct in situ stabilisation)


I. The procedures for site preparation are similar to those required for most soil stabilisation products.
II.Prepare the pavement to final road level and profile before application of the stabiliser.
III.Maintain the pavement material to be stabilised at or about optimum moisture, or drier.
IV. Where it is reasonable to expect the stabilising machinery will break up the old bitumen or asphalt seal, it should be broken up to
     form part of the new stabilisation.

Supply of RBI Grade-81 Powder

Bulk
RBI Grade-81 is available within India as bulk powder delivered to site in bulk tankers with a nominal capacity of 26-27 tonnes.
RBI Grade-81 powder has a high level of fluidity. Bulk density is normally in the range 0.8 to 1.0.

Bulk Bags
Supplies are available in one tonne bulk bags

Small Bags Supplies of 20kg bags are available.

Application and Mixing of RBI Grade-81 Direct into Pavement with Spreading and Stabilising Machinery

The bulk tankers will pump RBI Grade-81 direct into the spreader truck or mobile storage tank at or near to the work site. RBI Grade-81 is spread from the spreader truck on to the pavement surface.

Compaction

Good compaction is absolutely essential for base materials stabilised with RBI Grade-81. The stabilised material is very adhesive and has a strong resilience. It is virtually impossible to excessively compact RBI Grade-81 stabilised materials with conventional road compaction equipment.
RBI Grade-81 pavements compact readily and it is not difficult in most instances to achieve 100% or greater compaction, providing moisture levels are at or around optimum.
We strongly recommend initial compaction be with a combination of a vibrating padfoot roller (using maximum amplitude vibration where it is not a risk to buildings) and rubber tyred rolling.
Grading and shaping of the pavement should be carried out during compaction as necessary and appropriate to achieve the best results.
For final compaction we recommend the use of a rubber tyred roller and smooth drum steel-vibrating roller. The pavement materials should be kept damp using a water cart during the compaction, but NOT TOO WET! If the surface becomes excessively wet the pavement may stick to the steel drum roller and form clods around the drum. This applies to the padfoot roller as well as the smooth drum roller.

Pavement Grading and Surface Preparation

The surface and material should be kept damp and as close to optimum as is practical whilst the work is taking place. There are normally no time constraints and the work or re-working may take place over several days, even after days under traffic. We recommend where possible the basic compaction be completed within the first 24 hours.

At the completion of the work, and/or at the end of every day's work, the unsealed surface should be dampened down to the point where a rubber tyred roller may be used to apply a slurry finish. Traffic may use the pavement after the application of the slurry finish and, if required, the base may be re-worked the next day.

The dampening of the finished surface and, where practical, the slurry finish, are most important and essential as this helps seal and "close off' to form the interim seal of the fully bound impervious flexible pavement.

In the absence of a rubber tyred roller, traffic (if there is sufficient} may be used to achieve a "close off' (slurry) to form the interim seal.

If, at the end of the day, time is limited to permit the slurry finish, the road should be dampened and allowed to operate under traffic overnight. The slurry finish can be done the next day.

With sophisticated machinery, it is possible to build about 10km of roads per day by using RBI Grade-81.