Name of Work Na - e-Tendering

and special and other articles and appliance of every sort kind and description
whatsoever intended or used therefore.
45. MIX DESIGN :
45.1 The following instructions shall be followed as regards preliminary design of mix and
methods of batching of plain cement concrete and reinforced cement concrete. These
instructions should be treated as supplementary to the relevant provision in the specifications
for the respective items contained in the book of standard specifications and will override the
provisions contained therein wherever they are contrary to the following instructions.
The preliminary mix design and batching for various grades of concrete shall be
governed by the following guidelines.
Concrete Grade
Guidelines
1) Upto M-15: This should only be ordinary concrete. No change may be prescribed in
the present practice as regards preliminary design of mix and permitting
volume batching. Only cement to weight batched
2) M-20 to M-25 : Preliminary mix design must be carried out for these mixes. However,
weight batching shall be insisted for cement .only for concrete m-20 and
above
3) M-25 and above : Preliminary mix design must be prepared for such mixes Weight
batching shall be insisted for cement fine aggregate and course
aggregate.
45.2 For the grades of concrete M-20 and above the preliminary mix design shall be carried
out from the approved laboratory.
(1) The charges for preliminary design, of concrete mix shall be entirely borne by the
contractor.
(2) For grades of concrete M-20 and above where cement is to be used by weight, the
cost of extra cement required to make-up the under-weight bags shall be borne by the
contractor.
(3) For the items of concrete of grades lower than M-20 and other items in the
agreement, where cement is not to be used by weighment, the cement bags as received
from the manufacturer and supplied to the contractor under Schedule 'A' shall contain
cement of 50 Kg. net weight.
45.3 The admixtures such as plasticizers/super plasticizers for concrete grade M-20 and
above shall be used as directed by Engineer in charge depending upon specific
requirements. No extra payment s on this account will be admissible
Contractor No of Correction Deputy Engineer 66