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Performance Evaluation Report on Rural Roads Constructed Using CRRI-Bitchem Cold Mix in Different District of Assam during 2008-2009

Table 5. Quantity of Binder (CRRI-BitChem Cold Mix Binder) for
20mm thick Premix Carpet
Item Quantity per 10 sqm. of Road
Surface
For 13.2 mm size coarse aggregate 13-15 kg (MS Grade)
For 11.2 mm size coarse aggregate 6-7 kg (MS Grade)
Total 19-22 kg.

Table 6. Quantity of Binder (CRRI-BitChem Cold Mix Binder) for Seal Coat
Item Quantity per 10 sqm. of Road
Surface
For Type A Seal Coat (Liquid Seal Coat) 12-14 kg (RS-2 Grade)
For Type B Seal Coat (Premix Seal Coat) 10-12kg (SS-2 Grade)

5.3 Machineries for laying of Premix Carpeting

The equipments required for premixing of cationic bitumen emulsion with aggregates are of the following:

a) Concrete Mixer – for small or medium volume of work

b) WMM Plant or a continuous Cold Mix Plant – for huge volume of work where continuous operation is
necessary.

5.4 Process for laying of Premix Carpeting

a) Surface preparation – Clean surface, already primed as per specifications is required for starting of
carpeting works.

b) Preparation of Binder – Before opening the emulsion drums it should be rolled sufficiently so that there
will not be any storage sedimentation.

c) Preparation of Premix - Tack Coat should be as per specifications for starting the premixing activities.
Premixing can be done with the help of a concrete mixer machine, a continuous cold mix plant or by hand
mixing. Specific quantity of emulsion should be added with a specific volume of aggregate as directed by
the Engineer-In-Charge. For proper coating and breaking, guidance from the emulsion manufacturer is
necessary.

d) Spreading and Rolling – The premix materials shall be spread according to the setting and breaking time
of emulsion. The mix should be spread uniformly with required camber / super-elevation. A smooth
wheel tandem roller of 8-10 MT shall be used for compaction.

e) Application of seal Coat – Seal Coat shall be applied 4 to 6 hours after laying of Cold Mix
premix carpet. The mixing , spreading and rolling of seal coat depends upon the breaking
and setting of emulsion.

QSP/MR/19/ ACED/BTCM/214/2013 CSIR-NEIST/CNP-462