construction materials in concrete bgg.ppt

construction materials in concretegg

1. CONCRETE MATERIALS
Technology of Material II
TKS 4012
Prepared by [email protected]

2. Overview
What is concrete made of?
Why do we use concrete?
How do we use concrete?
Where is concrete used?
Why is concrete often reinforced?
Why do we use solid waste as an
aggregate in concrete?

3. Constituent Materials
Cement
Water
Coarse aggregate
Fine aggregate
Admixtures

4. Cement

Cement is a building material
made by grinding calcined
limestone and clay into a fine
powder.

When mixed with water, it will
harden as it undergoes chemical
changes.

5. Cement (cont’d)

Portland Cement: limestone,
shale, and clay.

Chemical Composition:

CaO (lime)
Al
2
O
3
(Alumina)
SO
3 (Sulfite)

6. Water

We all know what water is …!

In general, consumable water can be
used in concrete making.

7. Coarse aggregate

This is an aggregate that is
usually close to ¼ inch (5 mm)
in diameter or larger.

8. Fine aggregate

This is an aggregate that is
usually very small/fine, such as
sand (< 5 mm).

9. Admixtures
ASTM C 494 Descriptions of Admixtures Types:

A : water reducing admixtures

B : retarding admixtures

C : accelerating admixtures

D : water reducing & retarding admixtures

E : water reducing & accelerating admixtures

F : water reducing, high range & accelerating
admixtures

G : water reducing, high range & retarding admixtures

10. Concrete
A mixture of two
components:

Paste (25-40%)

Aggregates (60-75%) and
Air

11. Paste
Comprises of:

a binder (cement)

Water

Entrapped air or
purposely
entrained air

12. Mortar
Comprises of:

a binder (cement)

Fine aggregate

Water

13. The chemical reaction of paste:
2(3CaO.SiO
2
) + 6H
2
O
3CaO.2SiO
2
.3H
2
O + 3Ca(OH)
2
2(3CaO.SiO
2
) + 6H
2
O
3CaO.2SiO
2.3H
2O + 3Ca(OH)
2
Where:
CaO.SiO
2
: calsium silicate
H
2
0 : water
CaO.SiO
2.H
2O: tobermorite (hard)
Ca(OH)
2
: calsium hydroxide (free)
Chemical reaction

14. Aggregates
Comprises of :

Sand (fine aggregates)

Gravel or crushed stone
(coarse aggregates)

15. Volume distribution
Percentage volume distribution
of materials in concrete:

16. Mixing

The main concern is characteristic
compressive strength based on
specific design codes.

Manual or Machine?

17. Placing

Considering about the height of fall
to avoid segregation (pumping and
vertical bucket).

Compacting by using a vibrator or
manual? Internal or external?

18. Curing

Over time concrete will cure, which is
a hardening process.

Concrete has a 28 day curing time,
this is the amount of time it takes to
be considered completely cured.

19. Forms

A form is the mold for setting
concrete into a desired shape.

20. Why is concrete used?
Economics

Inexpensive, readily available
Material Properties

Long Lasting

Molded into a desired shape

Great insulator
Hard

Great Compressive Strength

21. Waste aggregates

Why is it important to use solid waste
as an aggregate in concrete?

22. 
Environmental Preservation

New Material Properties

Recycled tires (crumb rubber)

Insensitive to water

Broken Bricks

Fire resistant

Plastic

Greater resistance to freeze-thaw cycles

Glass, PVC, Wood Chips and several
others
Waste aggregates (cont’d)

23. Fresh Concrete
Properties of Fresh Concrete:

Workability

Hydration

Setting time

Hardening

Segregation

Bleeding

24. Workability

25. Hardened Concrete
Properties of hardened concrete:

Strength (compressive & tensile)

Unit Weight

Resistance to freezing and
thawing

Permeability and water tightness

Abrasion Resistance

Volume Stability (creep &
shrinkage)

Control of cracking

26. Compressive strength

27. Influence factors
Influence factors on compressive
strength of concrete:

Age

Density

w/c ratio

Amount of cement

Type of cement

Type of aggregate

28. Types of concrete
Based on its compressive strength:
①Plain Concrete (<
10MPa)
②Ordinary/Normal Concrete (10 – 30MPa)
③Prestressed Concrete (30 –
40MPa)
④High Performance Concrete/HPC(40 – 80MPa)
⑤Ultra High Performance Concrete/UHPC (> 80MPa)

29. Types of Concrete (cont’d)
Based on its unit weight:
1. Ultra Lightweight Concrete(< 1.000 kg/m
3
)
for non structural
2. Lightweight Concrete(1.000 – 2.000 kg/m
3
)
for lightweight structure
3. Normal Concrete (2.000 – 3.000 kg/m
3
)
for structural
4.Heavyweight Concrete (> 3.000 kg/m
3
)
for radiation shield structure

30. Any Questions?
Thanks for your kind attention!