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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
Site Preparation (for direct in situ stabilisation)
The procedures for site preparation are similar to those
required for most soil stabilisation products.
Prepare the pavement to final road level and
profile before application of the stabiliser.
Maintain the pavement material to be stabilised
at or about optimum moisture, or drier.
Where it is reasonable to expect the stabilising
machinery will break up the old bitumen or
asphalt seal, it should be broken up to
of the new stabilisation.
Supply of RBI Grade-81 Powder
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.
Supplies are available in one tonne bulk 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.
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.