IS 456 : 2000
Table 1 Permissible Limit for Solids
tCtaus« 5.4)
n
ii)
iii)
iv)
l'crDli~~ible
'Iesred as per
51
Nil,
Limit,
Mllx
Organic
Inorganic
Sulphates (as SO)
Chlorides (as CIl
IS ~02~ (Part IS)
IS ~025 (Purt Ill)
IS ~02'i (Part 24)
IS .1025 (Part ~2)
2001ll!!!1
11M10 mg!1
400 mg/l
2IM)() IIIg!1
for concrete 1101 coutaining
embedded steel and
~(JO
1IIg/\
I<Jr reinforced concrete work
v)
Suspended mailer
IS 3025 (Part 17)
2 000 1lIg11
5.6.1 All reinforcement shall he free from loose mill
scales. loose rust and coats of paints. oil. mud or any
other substances which may destroy or reduce hondo
Sand blasting or other treatment is recommended to
dean reinforcement.
5.4.4 Water found satisfactory for mixing is also
suitable for curing concrete. However, water used for
curing should not produce any objectionable stain or
unsightly deposit \10 the concrete surface. The presence
of tannic add or iron compounds is objectionable,
5.6.2 Special precautions like coating (If reinforcement
may be required for reinforced concrete clcmenIs in
exceptional cases and for rehabilitation of structures.
Specialist literature may he referred to in such cases.
5.5 Admixtures
5.5.1 Admixture. if used shall comply with IS 9103.
Previous experience with and data (IIi such materials
should he considered in relation to the likely standardsof
supervisionand workmanshipto the work being specified.
5.6.3 The modulus of elasticity of steel shall be taken
as 200 kN/l1llJ1·~. The characteristic yield strength of
different steel shall be assumed as the minimum yield
stress/0.2 percent proof stress specified in the relevant
Indian Standard.
5.5.2 Admixtures should not impair durability (If
concrete nor combine with the constituent to form
harmful compounds nor increase the risk of corrosion
of reinforcement.
13.7 Storage of'Materials
5.5.3 The workability, compressive strength and the
slump loss of concrete with and without the usc of
admixtures shall be established during the trial mixes
before lise of admixtures
Storage of materials shall he as described in IS 40K2.
6 CONCRETE
6.1 Grades
5.5.4 The relative density of liquid admixtures shall
he checked for cadi drum containing admixtures and
compared with till' specified value before acceptance.
The concrete shall be in grades designated as per
Tanlc 2
5.5.5 The chloride content of admixtures shall
be independently tested fill e ach hutcl) before
acceptance.
6.1.1 The characteristic strength is defined as the
strength of material below which not more than
5 percent of the test results arc expected to fall.
5.5,6 If two or more admi xture s art' used
simultaneously in the same concrete mix. Jala should
be obtained to assess their interaction and to ensure
their compatibility,
6.1.2 Tile minimum grade of concrete for plain and
reinforced concrete shall be as per Table 5.
6.1.3 Concrete of grades lower than those given in
Table 5 may he used for plain concrete constructions.
lean concrete, SImple foundations, foundation for
masonry walls and other simple or tcmporury
reinforced concrete construction.
5.6 Reinforcement
TIll' reinforcement shall be any of the following:
a) Mild steel and medium tensile steel bars
conforming to IS 432 (Part I).
6.2 Properties of Concrete
6.2.1
h) High strength deformed steel bars conforming
to IS 1786.
IIIClI'(/.I'(,
of Strength with Agi'
There is normally a gain of strength beyond 2S days.
The quantum of increase depends upon the )!radc and
type of cement, curing and cnvuoruucnral conditions,
etc. The design should 1)(' h:1S,xl on 2x dav-, charactcristic strength "f com.r. " 'lIlkss there is a evidence II I
c) Hard-drawn steel wire fabric conforming to
IS 1566.
d) Structural steel conforming to Grade A of
IS 2062.
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