Tender Document - irpmu.railnet.gov.in

deposited at the Mixing site for not less than 8 hours before use and should be
got tested and approved by the Engineer.
23.4 WATER: Clause 5.4 of IS: 456-2000 shall be applicable in place of clause 4.3 of
IRS Concrete Bridge Code. However, in case of pre-stressed concrete work the
permissible limit of solids must satisfy the following:
Permissible Limit.
Organic
Inorganic
Sulphates (SO4)
Chlorides.
Suspended matter.
(Max.)
200mg/ lit.
3000mg/lit.
500mg/lit.
250mg/lit.
2000mg/lit.
The PH value should not be less than 6.
23.5 STORAGE OF CEMENT: Cement shall be stored above the ground level in
perfectly dry and watertight sheds and shall be stacked not more than eight bags
in height. Wherever Bulk storage containers are used, their capacity should be
sufficient to cater to the requirements at site and should be cleaned at least once
in every 3 to 4 months.
24.0 ADMIXTURES FOR CONCRETE
24.1 No Admixtures shall in general be allowed. Railways may however, permit or
direct admixtures for specific purpose for which specifications will be drawn and
approved in advance. Nothing extra shall be payable for the admixtures and the
cost of the same shall be deemed to have been catered for in accepted item
rates. To improve the workability of concrete and cement grout admixtures
conforming to IS: 6925 and IS 9103 maybe permitted as directed by Engineer-incharge
subject to satisfactory proven use. The decision of Engineer in-charge
shall be final in this case. Admixtures generating hydrogen, nitrogen or
containing chlorides shall not be used.
25.0 MANUFACTURE, PLACEMENT & CURING OF CONCRETE:
25.1 Manufacture:
25.1.1 Mixing of concrete shall conform to requirements in clause 10.3 of I.S :456:
2000. Mixing for concrete for controlled concrete and pre-stressed concrete work
shall be done, unless otherwise agreed by Engineer-in-charge by batch type
mixer, which shall comply with IS: 1791 or other such type as the Engineer-Incharge
may approve.
OS/Works 56