Concrete Technology ppt

1. CONCRETE TECHNOLOGY
-G.BASKAR SINGH

2. INGREDIENTS OF CONCRETE
• Binder- Cement
• Filler / Inert materials- fine and coarse
aggregate
• Lubricator- water
• Cement discovered by- Mason Joseph
Aspdin(1824)
• RCC discovered- Joseph Monier
• Father of civil Engineering- John Smeaton

3. Cement
manufacture of Portland cement
• Grinding together – calcareous (Limestone
chalk) and argillaceous (shale or clay) and
other silica.
• Temperature – 1300ᵒ C to 1500 ᵒ C
• Gypsum about 2 to 3 % is mixed to prevent
flash setting.
• Cement surface area- 2250- 4000 cm2/g (or)
m2 / kg

4. Chemical composition of OPC
Oxide composition Percentage Functions Effects of Excess
composition
Lime (CaO) 60 – 65 Controls strength
and soundness
(volume changes)
Makes cement
unsound
Causes the
cement to expand
and disintegrate
Silica (SiO2) 20 – 25 Gives Strength Strength of
cement increase
but at the same
time, its setting
time is prolonged
(i.e. causes the
cement to set
slowly)
Alumina (Al2O3) 4-8 Responsible for
quick setting
Weakness of the
cement

5. Oxide
composition
Percentage Functions Effects of
Excess
composition
Iron oxide
(Ferrous Oxide)
Fe2O3
2-4 Gives colour
and helps in
fusion of
different in
gradient
Magnesium
Oxide (MgO)
1-3 Imparts
colour and
hardness
Makes the
cement
unsound
Not greater
than 6% as per
IS
Gypsum(CaSo4.
2H2O)
2 -3 Delays the
setting of the
cement

6. Composition of cement clinker
(Bogue’s Composition)
• C3S – Tricalcium Silicate
• C2S - Dicalcium Silicate
• C3A – Tricalcium Aluminate
• C4AF – Tetracalcium Alumino Ferrite

7. Function of Pure Compounds
Name of the compounds Percentage Functions
Tricalcium Silicate (C3S) 40-45
Responsible for early
strength
First 7 days strength due
to C3S
Produce more heat of
hydration
Better for cold weather
concrete
Less resistance to
sulphate attack
Dicalcium Silicate (C2S) 25-30
Responsible for later
strength (i.e. Long term
strength) after 7 days
strength.
Produces less heat of
hydration
More resistance to
sulphate attack

8. Name of the compounds Percentage Functions
Tricalcium Aluminate (C3A) 11
First compound which
reacts with water and leads
to “ FLASH SET”
Responsible for quick
setting property
Produces more heat of
hydration
Reason for most of the
undesirable properties of
cement
Tetra calcium Alumino
Ferrite (C4AF)
9
Higher resistance to
sulphate attack than the
hydrates of C3A
Low heat hydration than
C3A.

9. Manufacturing Process
• Grinding & Mixing of Raw Material
• Wet process- mixed with 35 – 50 % of H2O
• Dry process
• Semi process- Mixed with 10-14% of H2O

12. Physical Properties of OPC
Fineness shall be less than 10% when sieved
in IS sieve nos.
Initial setting time : not less than 30 minutes
Final setting time : 10 hours Vicat apparatus
Soundness : shall not be more than 20 mm (
Lechatlier apparatus)

13. Hydration of Cement
The chemical reaction between cement and
water
Unit for heat of hydration- Calorie/gram (or)
Joules/Gram
Measured by – Calorimeter or vacuum flask
set
The descending order of heat of hydration
C3A>C3S>C4AF>C2S
Descending order of strength
C3S>C2S>C3A>C4AF

14. Role of Gypsum
Gypsum control the initial setting time of the
cement
% Gypsum setting time (setting slow)
% Gypsum setting time ( sets quickly)
If excess of gypsum added (>5%) it causes
FLASH SET
Gypsum produce the chemical formation with
C3A is called “ETTRINGITE” (100 % volume
Changes 227% volume increase in Ettringite)

15. • CaCo3  CaO + CO2
• CaO + H2O  Ca(OH)2
• This process can volume increase this
phenomenon known as “Slaking”
• Excess of water content added in cement
(W/C Ratio High) they produce the “capillary
Pores” (Bleeding)

16. Hydration physical change
Addition of water
Plastic workable
paste
Initial set
Stiff and workable
paste
Final set
Rigid solid gaining
strength with time

17. Hardening of cement
• The gain of strength of a set of cement paste,
although during setting the cement paste
acquires some strength.
• Coefficient of hardness of cement Dony’s
Testing Machine.
• Specific surface area α 1/ (size of the particle)
• Specific surface area = 3/ ρ.r
• r= radius of the particles

18. • Specific surface area Size of the particle
• Specific surface area heat of hydration
• quantity of water , shrinkage limit , rate of
hydration and initial setting time.

19. Water requirement for hydration
• C3S requires 24% and C2S requires 21% .
• Average of 23% of water by weight of cement
is required for chemical reaction with
Portland cement compound (fully hydrate
cement of pure compounds) chemical
compound water or bound water.
• Addition 15% by weight of cement is required
to fill up the gel – pores
• Total requirement of water is 23 + 15 = 38%

20. • Excess of water causes “ capillary cavities”
• 1 cement bag (50 kg) = 35 liters

21. Setting time of cement
Plastic cement changes to a solid mass
Type of Cement
Initial setting
time
Final setting time
Ordinary
Portland cement
and Rapid
hardening
concrete
30 min 10 hours
Low heat cement 60 min 10 hours
Masonry cement 90 min 24 hours
Quick setting
cement
5 min 30 min

22. Testing of cement
Field test
1. Visual test for colour and
presence of lumps
2. Adulteration test for physical
properties
3. Strength test
Lab test
1. Fineness
2. Noraml consistency
3. Setting time
4. Soundness
5. Strength (compressive strength
and tensile strength)

23. • Colour – Greenish Grey (OPC)
• Lumps caused the presence of moisture of
water content. (reject/remove the cement
bag)
Period of storage 28 days strength (%)
Fresh 100
3 months 80
6 months 70
12 months 60
24 months 50

24. Lab test
Fineness test
IS sieve method
IS sieve no: 9
OPC-> 10 % residue
RHPC-> 5%
LHC -> 5%
Blaine’s Air permeability
method
Measured in specific surface
area
(area/ unit mass)

25. Blaine’s Air Permeability method

26. Fineness of cement is expressed as
specific surface area

27. Normal Consistency
Test/Initial/Final Setting Time

29. • Vicat apparatus
• With plunger having diameter=10mm
• Length=40 to 50mm.
• Plunger penetrate to a depth of 33-35mm
from the top or 5 to 7 mm form the bottom
of the vicats mould.
• 33% basic water content for normal
consistency.
• Initial / final setting time plunger diameter=
1mm
• Length= 40 to 50mm

30. Standard consistency test to be conduct and
determine the other test. (% of water required)
• 1. setting time-vicat’s Apparatus
• 2. soundness test-Le-Chatlier Apparatus
• 3. compressive strength- cube test
• 4. tensile strength- Briquettes mould
• Generally the water required to form a paste
of normal consistency is 33-35%.

31. S.NO Type of Test % of water Required
1. Normal
consistency Test
25 to 35 %
2. Initial Setting Time 0.85P
3. Soundness 0.78P
4. Compressive
Strength
P + 3% of water (or) (P/4) + 3% of
combined weight of sand and
cement.
5. Tensile Strength (P/5) + 2.5% of combined weight of
sand and cement.
P = percentage of water required for normal consistency test.
Temperature = 27 + -2 C
Humidity = 90%

32. Soundness Test
Le-Chatlier Apparatus

33. Soundness Test
• Done by Le-Chatlier Apparatus
• The unsoundness in cement is due to the
presence of excess of lime and magnesia.
• Therfore magnesia content in cement is
limited to upto 6% only. As per IS code.
• If the expansion is more than 10mm the
cement is said to be unsound & those cement
should be avoided.
• The Le-Chatelier test detect unsoundness due
to free from lime only.

34. Soundness Test
Auto clave method

35. • Autoclave test which is sensitive to both free
magnesia and free lime.

36. Cement Specific Gravity test
Le-Chatelier Flask

37. Cement Compressive Strength
• Done by cement mortar (1:3) cubes.
• Size of cube mould-7.06 cm (area=50 cm2)
• Ennore sand used-Standard sand (850µ -
600µ)
• Water = (P/4) + 3% of compound weight sand
and cement used.

38. COMPRESSIVE STRENGTH Mpa
S.NO TYPE OF
CEMENT
COMPRESSIVE STRENGTH IN Mpa
3 days 7 days 28 days
1. OPC 33 16 22 33
2. OPC 43 23 33 43
3. OPC 53 27 37 53

39. PERCENTAGE OF STRENGTH
GAINED
AGE % OF STRENGTH GAINED
1 DAY 16%
3 DAYS 40 – 50 %
7 DAYS 65 % or 2/3
14 DAYS 90%
28 DAYS 99%

40. Cement Tensile strength
• Shape of mould – Briquettes.
• Cement mortar ratio – 1:3
• Ennore sand – standard sand.
• Water = (P/5) + 2.5% of compound weight of
sand and cement.
• Minimum tensile strength.
– 1 day and 3 days = 2 Mpa.
– 7 days = 2.5 N/mm2.
– Tensile strength = 10 to 15% of compressive
strength

41. TYPES OF CEMENT
• RAPID HARDENING PORTLAND CEMENT
(RHPC) (IS 8041-1990)
• Also known as High early strength concrete
• rapid hardening property is achieved by
higher C3S content and by finer grinding.
• More heat of hydration.
Uses:
1. Early removal of form work is possible.
2. Road repair works.

42. • Setting Time:
• OPC = RHC
Compressive Strength:
1 day RHPC = 3 Days OPC
3 Days RHPC = 7 Days OPC
This cement is not suitable for Mass
constructions .ex. Dam

43. • Low Heat Cement (IS 12600-1989)
• Manufactured by reducing the percentage of
C3S and C3A.
• Increasing the percentage of C2S.
• Heat of hydration is lesser than of OPC.
• Setting time:
• IST=> 60 Min
• FST=> 10 Hours
• Suitable for mass concrete. Such like as dams,
bridges, retaining wall etc.

44. • Suitable for hot weathering conditions
• Suitable for more resistance for chemical and
sulphate attack.

45. • Sulphate Resisting Cement. (IS 12330-1988)
• Similar to OPC except it contains more silicates
and less quantity of aluminates.
• Used for underwater structures particularly
exposed to alkali action.
• Percentage of C2S & C3S
• Percentage of C3A & C4AF
• C3A strictly limited to 5% (i.e. has high
silicate contains)

46. • Portland Slag Cement (PSC) (IS 455-1989)
• Manufactured by mixing Portland cement
clinker with blast furnace slag about 25-70 %
of mass of mixture.
• Ground-granulated blast-furnace
slag (GGBS or GGBFS) is obtained by
quenching molten iron slag (a by-product of
iron and steel-making) from a blast furnace in
water or steam, to produce a glassy, granular
product that is then dried and ground into a
fine powder.
• Heat of hydration Durability

47. • Used in marine works.
• Highly resistant to sulphate attack hence
useful for foundation works where aggressive
chemical conditions exists.
• Composition of slag:
• Cao – 45%
• SiO2– 33%
• Al2O3 – 10%

48. • Portland Pozzolana Cement (IS 1489-1991)
• Pozzolana : fly ash, burnt clay and pumicite.
• PPC = OPC clinker + pozzolana material ( 15%
- 35%)
• CaO + Pozzolana + water = C-S-H (gel)
(Tobermite gel)
• Compressive strength
• 7 or 14 days PPC not equal to OPC
• 28 days PPC = OPC

49. • Advantages
• Better workability (ball bearing effect)
• Low heat of hydration
• Economical cost
• Less permeability for concrete structure
• More resistance for chemical attack
• PPC gives more volume of more than OPC
(more finer than OPC finer)

50. • Uses of PPC:
• For hydraulic structures such as dams, weir
etc.
• For marine constructions
• For mass concrete structures such likes dam,
bridges piers and raft foundations.
• For sewer and sewage disposal works etc.

51. • High Alumina Cement (HAC) (IS 6452-1989)
• Its produced by fusing together a mixture of
lime stone (or) chalk + bauxite
• % of C3A (about 35%)
• Heat of hydration is high.
• Uses:
• Used in refractories, kilns,chimney, chemical
plants and other workshops. Where high
temperature are involved.

52. • Advantages
• Quick setting and attain high ultimate
strength in short period.
• IS Code recommended
– Not mixture with other type cement
– Don’t added accelerator with HAC

53. Quick setting cement
• Obtained by reducing the Gypsum content at
the time of grinding. ( also known as Gypsum
free cement)
• Setting time
• IST = 5 min, FST = 30 min.
• Uses:
• Under water construction where pumping is
involved.
• Grouting operation

54. White cement IS 8042-1989)
Raw materials – white chalk (or) Lime stone &
China clay.
Iron oxide – Nil (or) Limited to 1 %.
Uses:
Architectural works
Fixing tiles etc.

55. Colored Cement
• Commercial term used for colour cement =
Colour cement – “Colocrete”.
• Another name is “snowcem”
• Obtained by adding pigments upto 10% to the
white cement during grinding.

56. Chromimum oxide Green colour
Cobalt Blue colour
Iron oxide in
different properties
Brown, Red, Yellow
colour
Manganese oxide Black brown
coloured cement

57. • Uses :
• Finishing of floors, external surfaces
• Artificial marble, windows sill slabs.
• Textural panel faces etc.

58. Hydrophobic Cement (IS
8043:1991)
• Where there is plenty of rainfall high air
moisture level.

59. Air Entraining Cement
• Alternate freezing & thawing action (for cold
region)
• Advantages
• Greater resistance to frost attack
• Strength durability

60. Grade of cements
• Grades of cement is based on Crushing
Strength of a cement mortar cube of size
70.71 mm (surface area of 50 cm2) cured for
28 days.
• Grade 33
• Grade 43
• Grade 53
• Grade 53 will have more shrinkage compare
to other grades, but higher early strength. Its
used in quality concretes, prestressed
concrete etc.

61. Aggregates
• It is a important constituents in concrete.
• Its give body of the concrete, reduce shrinkage
and effect economy.
• The aggregates occupy 70 – 80 % of the
volume of concrete.
• Concrete has two phase materials,
• 1. paste phase , 2. aggregate phase.

62. Aggregates -sub headings
Classification Source Size
Shape Texture Strength
Specific gravity
and bulk
density
Moisture
content
Bulking factor
Cleanliness Soundness Chemical
properties
Thermal
properties
Durability Sieve analysis
Grading

63. Classification
• 1. normal weight aggregates
• 2. light weight aggregates
• 3. heavy weight aggregates
• We are discussed about only normal weight
aggregates only.
• Aggregates can also be classified on the basis
of the size of the aggregates as coarse and
fine aggregate.

64. source
• All natural aggregates materials originates
form bed rocks.
• There are three kinds of rocks namely,
igneous, sedimentary and metamorphic.

65. size
• The maximum size of the aggregate is 80mm.
• If we are using the largest possible maximum
size that could be conveniently used for
concrete making. And we will get result in
a. reduction of the cement content,
b. reduction in water requirement,
c. reduction of drying shrinkage.
• C.A = aggregate > 4.75mm
• F.A= aggregate <4.75 mm to 0.15 mm

66. shape
Classification Description Examples
Rounded Fully water worn or
completely shaped by
attrition
River or seashore
gravels; desert,
seashore and wind
blown sands
Irregular or partly
rounded
Naturally irregular or
partly shaped by
attrition, having
rounded edges
Pit sands and gravels;
land or dug flints;
cuboid rock
Angular Possessing well
defined edges
Crushed rocks of all
types; talus ; screes
Flaky Material, usually
angular, of which the
thickness is small
relative to the width
and or length
Laminated rocks

67. • Rounded particles produce smoother mix for a
given water cement ratio.
• Angular or flaky particles reduce workability
and demand more cement and water to give
specified strength of concrete mix.

69. ANGULARITY
• It is the absence of roundness. An aggregate particle,
which is more rounded, is less angular and vice versa.
• ANGULARITY NUMBER
• Angularity number of an aggregate is the amount (to
the higher whole number) by which the percentage of
voids in it after compacting in a prescribed manner
exceeds 33.
• Where, “33” is the percentage of volume of voids, in a
perfectly rounded aggregate. “67” is the percentage of
volume of solids in a perfectly rounded aggregate.
• The value of angularity number generally lies between
0 & 11. In road construction angularity number of 7 –
10 is generally preferred. (A.N 11 – 56% volume)

70. Texture
The particle surface are polished or dull ,
smooth or rough.
Its depends upon hardness, grain size, pore
structure and the structure of rock.
As surface smoothness is increase, contact
area is decrease.
If texture is highly polished particle will have
less bonding area.

71. Surface characteristics of
aggregates
Group Surface texture Examples
1. Glassy Black flint
2. Smooth Chert; slate; marble
3. Granular Sandstone
4. Crystalline Fine : basalt
Medium: limestone
Coarse: gneiss; granite
5. Honey combed
and porous
pumice

72. Strength
• The strength is dependant also on the bond between
the cement paste and the aggregate.
• The mechanical properties of the rock or aggregate
will influence the strength of concrete.
• The test for strength of aggregate is required to be
made in the following situations:
• 1. for production of high strength and ultra high
strength concrete.
• 2. when contemplating to use aggregate
manufactured from weathered rocks.
• 3. Aggregate manufactured by industrial process.

73. Aggregate impact value- Strength

74. • Aggregates are resistance of impact load.
• Metal hammer weight = 14 kgs.
• Instrument height = 38 cm
• No of blows = 15
• The aggregate passing through 2.36mm
• Aggregate impact value:
• For roads and pavement = 30%
• For other structural works = 45%

75. Aggregate crushing value
• Specimen shape = cylindrical shape
• Diameter and height = 25 mm.
• The cylinder subjected to compressive stress.
• Strength varies from minimum 45MPa to Maximum
545MPa.
• Size of the aggregate = passing 12.5 mm sieve and retained
on 10mm sieve.
• Applied load = 40 ton.
• The material crushed to finer than 2.36 mm .
• For road and pavement = 30%
• For other structural works = 45%
• A good avg. value of crushing strength of coarse aggregate
is about 200 N/mm2

76. Aggregate Abrasion Value Test
• Resistance to abrasion standard abrasion tests
are
• 1. Los Angle’s Test
• 2. Deval abrasion Test
• 3. Dorry Abrasion Test

77. Los Angle’s Test
• Resistance to wear and impact is evaluated by
this method.
• 5 to 10 kg specimen rotated at 30 to 33 rpm,
500 to 1000 revolutions depending on the
grinding of specimen.
• Abrasion value = (wt of aggregate passing
1.7mm sieve / total weight) x 100

78. Los Angle’s specifications
• For cement concrete construction < 16%
• For surface or wearing course of bituminous
mix <30%
• For base course of bituminous bound
macadam < 50%

79. Deval Attrition Test
• Particles are subjected to wear in an iron
cylinder rotated 10000 times, speed at 30 -33
rev/min.
• The proportion of material crushed finer than
1.7mm size .

80. Dorry Abrasion Test

81. • This test is not covered by IS specification.
• It is cylindrical specimen of 25 cm height and
25 cm diameter to abrasion against rotating
metal disk sprinkled with quartz sand.
• The loss in weight of the cylinder after1000
revolutions in 30rpm.
• One cycle = 22 revolution.
• Hardness = 20 – (loss in grams / 3)
• Abrasion value for good rock >17.
• A rock sample is less than 14 , it has
considered poor.

82. Modulus of Elasticity
• Its depends upon on its composition, texture
and structure.
• It will influence the properties of concrete will
respect to shrinkage and elastic behavior and
to very small extent creep of concrete.
• Its denoted by ‘E’

83. Bulk Density or Unit weight
• Its depends on the particle size distribution
and shape of the particles.
• Its gives valuable information regarding the
shape and grading of the aggregate.
• For a given specific gravity the angular
aggregates show a lower bulk density.
• If aggregate have minimum voids, that
aggregate is higher bulk density.
• its denoted by kg/liter or kg/m^3

85. Specific gravity
• Specific gravity is a measure of relative
density.
• The specific gravity is the density of a
substance divided by the density of water.
• Density is measured in the units kg/m3.
• The density of water at 4.0°C is 1000 kg/m3.
So, the specific gravity is a unitless number.

87. Absorption and moisture content
• Some of the aggregates are porous and
absorptive. This type of aggregate affect the
water /cement ratio and hence the workability
of concrete.
• The porosity of aggregate will also affect the
durability of concrete.