NATIONAL ALUMINIUM COMPANY LIMITED - Rites

maintaining of the Kuccha roads shall be the responsibility of the Contractor. The
transported material shall be neatly stacked as directed by the Engineer. Double handling of
materials shall be avoided as far as possible. However, depending on site condition
excavated materials carried beyond a lead of 500 m may also be required to be brought back
for filling purpose. Materials to be used for filling purpose shall be stone, sand or other
inorganic materials and they shall be clean and free from shingle, salts, organic m mmatter,
large
roots and excessive amount of sod, lumps, concrete or any other foreign substances which
could harm or impair the strength of the substances in any manner. All clods shall be
suitably broken to small pieces. When the materials are mostly rock boulders, these shall be
broken into pieces not larger then 150 mm size. Sand used for filling shall be clean, medium
grained and free from impurities. Fines less than 75 microns shall not be more than 20%. In
any case, the materials to be used for filling purposes shall have the prior written approval of
the Engineer. In case the materials have to be brought from pits / quarries, then it shall be
the Contractor’s responsibility for identification ion of such quarry areas, obtaining approval
from their use from concerned authorities, excavation / quarrying loading and carriage of
such material, unloading and filling at specified locations. The Contractor shall pay any fees,
royalties etc. that may have to be pain for utilizationof borrow areas.
16. 0 GALVANISING SING
All burrs and irregular edges of the structural steel members to be galvanized shallbe ground
smooth before galvanizing.Purity of Zinc to be used for galvanizing shall be 99.5 % as per IS :
209 ( latestedition ).The weight of the zinc coating shall be at least 610 Gms. /m2unless
noted otherwise.
17.0 CHEMICAL INJECTION GROUTING
Minimum, 12 mm dia ( NB ) threaded nozzle of suitable length, shall be provided over the
surface and along the construction joint line in a grid pattern at a spacing not excee exceeding 1.5
m c / c before concreting operation. Adequate precaution shall betaken to keep the nozzles
plugged at both ends to prevent them from getting closedby concrete. For fixing of any
nozzle in set concrete suitable size hole shall be drilled, preferabl preferably y by using repercussive
hammer drill electrically operated, in grid pattern and grouting nozzle shall be fixed in these
holes. After the nozzles are fully set, neat cement slurry admixed with water soluble non -
shrink polymer / monomer based chemical shal shall l be injected through the net - work of
nozzles with low pressure grout pumps at a pressure of about 2.0Kgs. /cm2. Cement slurry
shall be prepared by mixing cement with non non-shrink shrink polymer/monomer @ 500 gm/50 kg bag
of cement and water, ensuring that Water: Cement ratio does not exceed 2 (by weight).
Wetter the structure, lesser should be the water cement ratio. The property of the
polymer/monomer should be such that when it is mixed with water @0.5% by weight of
water, the viscosity of the resultant solut solution ion (water and polymer/monomer) should not be
more than 1.2 centipoises. Plasticizing agent shall be added wherever required. The grouting
shall be started at very low pressure and increased gradually to a required pressure. The
grouting shall continue, ti till ll the hole refuses to take any further grout, even at an increased
pressure. Applied pressure shall not be more than the designed strength of the concrete.
After completion of grouting operation, the nozzles shall be sealed properly to the
satisfaction of the Engineer.
18.00 POLYMER MODIFIED CEMENTITIOUS COATING
18.1 Materials
Modified liquid polymer blend shall be a dispersion containing 100 % acrylic based polymer
solids. Polymer shall be mixed in the ratio of 1 cement: 0.5 polymer (for minimum solid
content of polymer 30%). Portland cement based dry powder. Clean, fine specially prepared
quartz sand approximately 0.6 mm size.
18.2 Mixing
The liquid polymer shall be stirred well and cement based powder shall then be added
Technical Specification:Sec-7, Civil
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