Topic from my Architectural Building Materials Course

1. Southeast University
Department of Architecture
ARC134
SHD
Building Materials

2. Inert material is any material that doesn't cause or promote any change.
Aggregate is a collection of inert granular material that comprises as
much as 60% to 80% of a typical concrete mix.

3. Scopes Fine Aggregate (FA) Coarse Aggregate (CA)
1 Definition Fine aggregates are small size filler materials in
construction.
Coarse aggregates are larger size filler materials in
construction.
2 Size of
Particles
Fine aggregates are the particles not larger than 3/16”
in diameter.
Coarse aggregates are the particles that retain from 3/16” to
2”diameter.
3 Materials Sand, surki, stone screenings, burnt clays, cinders, fly
ash, etc are used as fine aggregate in concrete.
Brick chips (broken bricks), stone chips (broken stones), gravels,
pebbles, clinkers, cinders etc. are used as coarse aggregate in
concrete.
4 Sources River sand or machine sand, crushed stone sand,
crushed gravel sand are the major sources of fine
aggregate.
Dolomite aggregates, crushed gravel or stone, natural
disintegration of rock are the major sources of coarse
aggregate.
5 Surface
Area
The surface area of fine aggregates is higher. The surface area of coarse aggregate is less than fine
aggregates.
6 Function in
Concrete
The voids between the coarse aggregate are filled up
by fine aggregate.
Coarse aggregate acts as inert filler material for concrete.
7 Uses Fine aggregates are used in mortar, plaster, concrete,
filling of road pavement layers, etc.
Coarse aggregates are mainly used in concrete, railway track
ballast, etc.

4. CONCRETE
Concrete, an artificial stone-like mass, is the composite material that is created by mixing
binding material along with the aggregate, water, admixtures, etc. in specific proportions.
Concrete= Binding materials + Inert materials + water
Binding materials: cement and lime
Inert materials: Aggregates (fine and coarse)

5. Function of water in concrete
1. To wet the surface of aggregate
2. To prepare a plastic mixture of various ingredients
3. Hydration of cementing materials to set and harden
Classification of concrete
1. Lime concrete :
• Lime, surki , khoa=1:2:5
• Concrete is to be laid in layers not exceeding 3” thickness
• Lime concrete is mainly used in foundation and terrace roofing
2. Cement concrete:
• Cement,sand and khoa = 1: 2: 4 or 1:3:6
• Ingredients are measured dry separately by volume
• The khoa or stones are soaked in water thoroughly
• Fine and course aggregate are mixed dry, then cement is added until the
color is uniform
• The required quantity of water is then added

6. Characteristic and Durability:
In ordinary structural concrete, the character of the concrete is largely determined by a
water-to-cement ratio. The lower the water content, all else being equal, the stronger the
concrete. The mixture must have just enough water to ensure that each aggregate particle
is completely surrounded by the cement paste, that the spaces between the aggregate
are filled, and that the concrete is liquid enough to be poured and spread effectively.
Another durability factor is the amount of cement in relation to the aggregate (expressed
as a three-part ratio—cement to fine aggregate to coarse aggregate). Where especially
strong concrete is needed, there will be relatively less aggregate.

7. Strength:
The strength of concrete is measured in pounds per square inch or kilograms per square
centimeter of force needed to crush a sample of a given age or hardness. Concrete’s
strength is affected by environmental factors, especially temperature and moisture.
In the process known as curing, the concrete is kept damp for some time after pouring to
slow the shrinkage that occurs as it hardens.
Low temperatures also adversely affect its strength. To compensate for this, an additive
such as calcium chloride is mixed in with the cement. This accelerates the setting process,
which in turn generates heat sufficient to counteract moderately low temperatures. Large
concrete forms that cannot be adequately covered are not poured in freezing
temperatures.

8. Advantages of concrete:
1. Ingredients are easily available
2. Concrete can easily handled and molder to any
desired shape .
3. Easy to transported from the place of mixing to
place of casting
4. The monolithic character of concrete gives it a
better appearance and much rigidity to the
structure.
5. The property of concrete to possess high
compressive strength makes a concrete
structure more
6. Economical than a steel structure.
7. More Economical
8. Ability to be cast
9. More Energy Efficient
10. Excellent Resistance to Water
11. High-Temperature Resistance
12. Fire Resistance
13. Aesthetic Properties
14. Ability to Consume waste
15. Ability to work with reinforcing Steel
Disadvantages of concrete:
1. Low Tensile Strength
2. Lower Ductility (Brittle)
3. Volume Instability
4. Formwork is needed
5. Low Toughness
6. Long Curing Time
7. concrete is required to be
reinforced to avoid cracks
8. Due to drying shrinkage and
moisture expansion concrete may
crack

9. Pre-stressed Concrete:
Another innovation in masonry construction is the use of pre-stressed concrete. It is achieved by either
pre-tensioning or post-tensioning processes.
• In pre-tensioning, lengths of steel wire, cables, or ropes are laid in the empty mold and then stretched and
anchored. After the concrete has been poured and allowed to set, the anchors are released and, as the steel
seeks to return to its original length, it compresses the concrete.
• Post-tensioning tendons, which are prestressing steel cables inside plastic ducts or sleeves, are positioned in the
forms before the concrete is placed. Afterwards, once the concrete has gained strength but before the service
loads are applied, the cables are pulled tight, or tensioned, and anchored against the outer edges of the concrete.

10. Special terms related to properties of concrete
A. Segregation :
• Separation of the constituents of a heterogeneous mixture so that
their distribution is no longer uniform
• The difference in the size of particles and in the specific gravity of the mixed
constituents are primary reason for segregation

11. B. Bleeding :
A form of segregation in which some of the water in the concrete mix tend to
rise to the surface of freshly placed concretes

12. C. Laitance :
• The formation of a crust of squeezed out mortar on the surface of concrete
•This is due bleeding and bad workmanship

13. Translucent concrete
Translucent concrete (also: light-transmitting concrete) is a concrete based building material with
light-trans missive properties due to embedded light optical elements — usually optical fibers.
Light is conducted through the stone from one end to the other. Therefore, the fibers have to go
through the whole object. This results in a certain light pattern on the other surface, depending
on the fiber structure. Shadows cast onto one side appear as silhouettes through the material

14. Due to bends in the fibers and rough nesses on the cut surfaces of the fibers, light
transmission is generally a bit less than half the incident light on the fibers, so given five
percent fibers, about two percent . As the human eye's response to light is non-linear, this
can still give useful daylighting.
Translucent concrete is used in fine architecture as a facade material and for cladding of
interior walls. Light-transmitting concrete has also been applied to various design products
Several ways of producing translucent concrete exist. All are based on a fine grain concrete
and only 5% light conducting elements that are added during casting process. After setting,
the concrete is cut to plates or stones with standard machinery for cutting stone materials
Translucent concrete has been
first mentioned in a 1935 Canadian
patent. But since the development
of optical glass fibers and polymer
based optical fibers the rate of
inventions and developments in
this field has drastically increased.

15. Fair-faced concrete
Be it for modern administrative buildings or for housing, fair-faced concrete is
becoming increasingly popular. Fair-faced concrete is not plastered or veneered; the
simple appearance of the concrete meets aesthetic requirements.
Fair-faced concrete refers to concrete surfaces with special requirements in terms
of concrete aesthetics and structure. We distinguish between four different classes
of fair-faced concrete:

17. Ferrocement concrete
Ferrocement is a construction material consisting of wire meshes and cement mortar.
Applications of ferrocement in construction is vast due to the low self weight, lack of skilled
workers, no need of framework etc.
Constituent Materials for Ferrocement
1. Cement, Fine Aggregate, Water, Admixture,
2. Reinforcing mesh, Skeletal Steel Coating

18. Properties of Ferrocement
•Highly versatile form of reinforced concrete.
•It’s a type of thin reinforced concrete construction, in which large amount of small
diameter wire meshes uniformly throughout the cross section.
•Mesh may be metal or suitable material.
•Instead of concrete Portland cement mortar is used.
•Strength depends on two factors quality of sand/cement mortar mix and quantity
of reinforcing materials used.

21. the Liquid stone

22. Cement Sand Khoa/Stone
Water-reserved Work 1 1.25 2
Cement Concrete Work 1 3 6
Normal RCC Work
( Slab, Beam,
Piling, Footing,
Foundation Grade beam )
1 2 (Sylhet) 4 (Stone chips)
RCC Work for Columns 1 1.5 (Sylhet) 3 (Stone chips)
Brick Work 1 5 -
Plaster 1 6 -
Tiles Morter+Grout 1 3 -
MIX RATIO

23. SHUTTERING x SHADES x TEXTURES x FORMWORK
Rust Infusion
Atelier Bardill
by Valerio Olgiati, Scharans,
Switzerland
Red iron oxide was added to
the concrete which lends the
façades a rusty umber hue.

24. SHUTTERING x SHADES x TEXTURES x FORMWORK
Aggregate Layering
Bruder Klaus Field Chapel by Peter
Zumthor, Mechernich, Germany
Large, rocky aggregate and tonal
variations between each layer of
concrete forms elevations that evoke
cliffs of sedimentary rock.

25. SHUTTERING x SHADES x TEXTURES x FORMWORK
Rough Timber Formwork
Sun Moon Lake Administration Office
of Tourism Bureau by Norihiko Dan
and Associates, Taiwan
A formwork of rough timber planks
was utilized to create these canyon-
like walls, leaving the impression of
wood grain on every surface.

26. SHUTTERING x SHADES x TEXTURES x FORMWORK