QUALITY CONTROL
OF
CONSTRUCTION MATERIALS
(Concrete)
by
K. RAMESH
Research Officer,
Engineering Materials Laboratory,
A.P. Engineering Research Laboratories,
Himayatsagar, HYDERABAD-500030.
Tests on cement concrete
(Strength Tests)
•
Compressive strength
•
Flexure strength
•
Modulus of elasticity
Compressive strength
•
•
•
Size of the cube = 15 Cm.
No. cubes = 3
No. of layers in a cube = 3
Name of the Test: Compressive Strength of Cement Concrete.
[ IS : 516 - 1959, IS:1199 - 1959]
1.Weight of Cement concrete
= 60 Kg for 6 No.s of 15 Cm cubes.
2.Mix proportion by weight
=
3.Water Cement ratio
=
4.Weight of Coarse aggregate in Kg
=
5.Weight of Fine aggregate in Kg
=
6.Weight of Cement in Kg
=
7.Weight of Water in Kg
=
8.Slump in mm
=
9.Type of slump
=
True/Shear/Collapse
10.Unit weight:
a.Volume of cylinder in l
(V)
=
b.Empty weight of cylinder in Kg
(A)
=
c.Weight of cylinder + Compacted concrete in Kg (B) =
B-A
3
a.Unit weight in Kg/m = ----------- x 1000 =
V
=
1.Compressive strength:
a.Cross sectional area of the 15 Cm cube
b.Observations:
S.No
.
Age of
testing
(days)
Compressive Load
(Kg)
(A)
Average
Compressive
Load (Kg)
P=(P1+P2+P3)/3
P1 =
1.
7
P2 =
P3 =
P1 =
2.
28
P2 =
P3 =
(Note: For each age of testing minimum 3 cubes shall be tested.)
=
225 Cm2
Average
Compressive
Strength (N/mm2)
=(P/A)/10.2
Flexure strength
•
Size of the specimens = 15 x 15 x 70 for MSA ≤ 40mm
= 10 x 10 x 50 for MSA ≤ 20mm
Modulus of elasticity
•
Size of the specimen = 15 Cm dia. & 30 Cm. height
Tests on cement concrete
(Workability & Other Tests)
•
•
•
•
•
•
•
•
•
Slump
Compaction factor
Vee-bee
Analysis of freshly mixed concrete
Density
Yield
Air content
Cement content of hardened concrete
Drying shrinkage
•
Moisture movement
Workability
•
Workability is defined as that property of freshly mixed
concrete or mortar which determines the ease &
homogenity with which it can be mixed, placed,
compacted and finished.
Workability tests
•
•
•
•
Slump test
Compaction factor test
Vee-bee test
Flow test
Slump test
•
Slump test indicates the behaviour of compacted
concrete cone under the action of gravitational force
Compaction factor test
•
Compaction factor test indicates the behaviour of fresh
concrete cone under the action of external force
Vee-bee test
•
Vee-bee test indicates the behaviour of fresh concrete
cone under vibration.
Suggested ranges of workability
as per IS:456-2000
S.No.
Placing conditions
Degree of Slump
workability (mm)
1.
Blinding concrete, shallow sections,
pavements using pavers
Very low
Use
C.F. test
2.
Mass concrete, lightly reinforced
sections in slabs, beams, walls,
columns, floors, hand placed
pavements, canal lining, strip footings
Low
25-75
3.
Heavily reinforced sections in slabs,
beams, walls, columns, slipform work,
pumped concrete
Medium
50-100
4.
Trench fill, insitu piling
High
100-150
5.
Tremie concrete
Very high
Use
Flow
tests
Flow test