Volume-IF - JantERmantER

DCPL-K4A02
The requirement of adequate structural strength is catered for by
the choice of proper grade of concrete by the Engineer. The
Contractor will strictly abide by the same in his design of concrete mix
installation. Notwithstanding anything mentioned in various tables
given in IS:456 giving specific values and degrees of workability for
different condition of concrete placing, minimum cement content and
maximum water-cement ratio for concrete exposed to sulphate
attack and for concrete to ensure durability under different condition
of exposure, strength requirement for different grades of concrete,
proportion for nominal mix concrete, values given in the tables in
IS:456, shall be followed.
Various trials shall be given by the contractor with specific
cement content on each trial . In some cases, plasticizers and
other admixtures may be necessary to achieve the desired results.
TABLE - I
STRENGTH REQUIREMENT OF CONCRETE
Specified Characteristic Compressive
Grade of concrete
strength of 15 cm Cubes at 28
days conducted in accordance
with IS:516 (All values in
N/Sq.mm)
Note -1:
M - 10 10
M - 15 15
M - 20 20
M - 25 25
M - 30 30
M - 35 35
M - 40 40
Nominal mix concrete of proportions 1:4:8 or 1:3:6 may be used as lean
concrete for simple foundations for masonry walls , below the reinforced
concrete foundations and mass filling . These mixes need not be designed.
TABLE - II
MIX PROPORTIONS (BY WEIGHT) EXPECTED TO GIVE
DIFFERENT DEGREES OF WORKABILITY WITH DIFFERENT
(PCA.774.S034sca2) V.II-D2/S-III : 13