CLE204 - Construction Materials and Technology is one of the Programme Cores offered for B.Tech - Civil Engineering under FFCS Curriculum at VIT Chennai.

1. CLE204 - Construction Materials and Technology
Unit I – Sources of Aggregates & Properties
Ramesh Kannan
Assistant Professor
School of Mechanical and Building Sciences
VIT Chennai, Chennai - 600127
1 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

2. Syllabus
Unit I - Sources of Aggregates & Properties
Physical and Mechanical properties of construction materials - commonly
used types of stones - Tests for stones, road aggregates and concrete
aggregates, properties of sand, BIS specification for testing of aggregates
- Bricks - Properties and testing methods for Bricks.
2 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

3. Physical Properties of Construction Materials
Physical Properties
The measurable properties which describes the physical state
(without altering its characteristics) of the materials are commonly
termed as Physical Properties.
The physical properties of construction materials includes specific
mass (density), specific gravity (relative density), specific
weight (unit weight), porosity, water absorption and so on.
3 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

4. 1. Density (or) Specific Mass
Density (ρ) is defined as the “ratio of mass per unit volume of a
homogeneous material”. This is commonly referred to as ‘volumetric
mass density’ or ‘specific mass’.
Density can also be represented in terms of weight as weight density
which is the “ratio of weight per unit volume of a material”.
ρ =
m
v
and ρw =
w
v
=
m.g
v
(1)
Where,
ρ = Density of the material, in kg/m3
ρw = Weight density of the material, in kg/m3
m = Mass of the material, in kg
w = Weight of the material, in kg
g = Acceleration due to gravity, in m/s2
(g = 9.81 m/s2
on Earth)
v = Volume of the material, in m3
4 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

5. The density of some of the important building and construction materials
are shown below.
0 2,000 4,000 6,000 8,000
Aluminium
Brick
Concrete
Glass
Limestone
Polystyrene Foam
Steel
Water
Wood (Pine)
Wood (Oak)
2,708
1,971
2,400
2,467
1,650
33
7,833
1,000
513
721
Density (in kg/m3
)
5 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

6. 1.1. Bulk Density
Bulk Density (ρb) is defined as the ratio of mass per unit volume of
a material in its natural state (with extrinsic voids and pores).
The intrinsic voids or pores, cracks, gaps and flaws, etc., present in
the materials are generally not considered for the determination of
bulk density.
For example, for a fired clay brick, the bulk density is calculated
based on its density of the constituent materials and macroscopic
pores developed due to the entrapped air only but not the mesoscopic
and microscopic pores, which is an intrinsic characteristic of brittle
materials.
ρb =
m
v
(2)
Where,
ρb = Bulk density of the material, in kg/m3
m = Mass of the material, in kg
v = Volume of the material, in m3
6 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

7. 1.1. Bulk Density – Dry & Wet Bulk Density
Bulk density is a property of granular materials and it is commonly
referred as ‘Density of Granual Materials’.
Bulk density can be categorized into Dry bulk density ρb(dry) and
Wet bulk density ρb(wet).
Dry bulk density is normally the bulk density of the material
Wet bulk density is the ratio of total mass of material (mass of
material + mass of water) to the total volume of the material (volume
of material + volume of water).
ρb(dry) =
m
v
and ρb(wet) =
mt
vt
=
m + mw
v + vw
(3)
Where,
mt = Total or apparent mass of the material, in kg
mw = Mass of the water, in kg
vt = Volume of the material, in m3
vw = Volume of the water, in m3
7 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

8. Example 1: Calculation of Bulk Density
Calculate the dry and wet bulk density of a structural fired clay brick of
dimension 19 × 9 × 9 cm with a standard frog of size 10 × 4 × 2 cm as
shown below. The weight of the brick which is dried naturally at 27 ± 1o
C
temperature is 2.76 kg and the weight of brick removed after immersed
and soaked in cold water for 24 hours is found to be 3.12 kg. The volume
of water consumed by the brick is 0.0009 m3
.
8 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

9. Solution: Given Data:-
‚ Dimension of brick, (L×B×D) = 19 × 9 × 9 cm = 0.19 × 0.09
× 0.09 m
=⇒ Total volume of brick, V = 0.19 × 0.09 × 0.09 cm =
0.001539 m3
ƒ Dimension of frog, (l×b×d) = 10 × 4 × 2 cm = 0.10 × 0.04
× 0.02 m
=⇒ Volume of frog, vf = 0.10 × 0.04 × 0.02 m =
0.00008 m3
=⇒ Volume of brick (dry), v = Total volume of brick, V –
Volume of frog, vf
= 0.001539 – 0.00008 m3
=
0.001459 m3
≈ 0.0015 m3
„ Mass of brick (dry), m = 2.76 kg (Initial Mass)
… Total mass of brick (wet), mt = 3.12 kg (Final Mass)
9 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

10. Solution: Given Data (Cont...):-
† Mass of water, mw = Total mass of brick, mt – Mass
of brick, m
= 3.12 – 2.76 kg = 0.36 kg
‡ Volume of water, vw = 0.0009 m3
=⇒ Volume of brick (wet), vt = Volume of brick (dry), v +
Volume of water, vw
= 0.0015 + 0.0009 m3
= 0.0024
m3
10 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

11. Dry bulk density and wet bulk density of a material is given by
ρb(dry) = ρb =
m
v
and ρb(wet) =
mt
vt
Dry bulk density, ρb(dry) = ρb =
m
v
=
2.76
0.0015
= 1840 kg/m3
Wet bulk density, ρb(wet) =
mt
vt
=
3.12
0.0024
= 1300 kg/m3
Answer
∴ Dry density of structural fired clay brick, ρb(dry) = 1840 kg/m3
and
Wet density of structural fired clay brick, ρb(wet) = 1300 kg/m3
11 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

12. 1.2. Density Index
Density Index (ρ0) is defined as the ratio of bulk density to the density of
same material.
ρo =
Bulk Density
Density
=
ρb
ρ
(4)
Where,
ρo = Density Index of the material (Constant)
ρb = Bulk density of the material, in kg/m3
ρ = Density of the material, in kg/m3
In general, the density index of almost all the building and construction
materials are less than or nearly equal to 1 but not exactly equal to
1 since there isn’t any perfect or ideal material exists whose density and
bulk density are the same.
12 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

13. Example 2: Calculation of Density Index
Calculate the density index of a structural fired clay brick whose density
and bulk density are 1971 kg/m3
and 1840 kg/m3
respectively.
Solution: Given Data:-
‚ Density of brick, ρ = 1971 kg/m3
ƒ Bulk density of brick, ρb = 1840 kg/m3
Density Index (ρo) of a material is given by ρo =
ρb
ρ
ρo =
ρb
ρ
=
1840
1971
= 0.933536 ≈ 0.94 (Constant)
Answer
∴ The density index of this structural fired clay brick is 0.94
13 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

14. 2. Unit Weight (or) Specific Weight
The unit weight (γ) of the material is defined as the weight per
unit volume of a material. This is commonly referred to as ‘weight
density’ or ‘specific weight’.
γ = ρw =
w
v
=
m.g
v
(5)
The relationship between density and unit weight of a material is
given by the following expression.
γ = ρ.g (6)
Where,
γ = Unit weight of the material, in kN/m3
ρ = Density of the material, in kg/m3
g = Acceleration due to gravity, in m/s2
(g = 9.81 m/s2
on Earth)
14 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

15. 2. Unit Weight (or) Specific Weight (Cont...)
The unit weight places an important role in the structural engineering
as it is used for the determination of loads that could possibly be
encounter in a building along with the angle of internal friction.
The comprehensive list of weight, density and unit weight of
commonly used building and construction materials are given in
Bureau of Indian Standard, IS 875-1 (1987): Code of Practice For
Design Loads (Other Than Earthquake) For Buildings And Structures,
Part 1: Dead Loads - Unit Weights of Building Material And Stored
Materials.
https://law.resource.org/pub/in/bis/S03/is.875.1.1987.
pdf
15 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

16. Example 3: Calculation of Unit Weight
Calculate the unit weight of a hardened Plain Cement Concrete (P.C.C)
cube whose density is found to be 2400 kg/m3
.
The unit weight (γ) of a material is given by γ = ρ.g
γ = ρ.g = 2400 × 9.81 = 23544 N/m3
= 23.544 kN/m3 ≈ 24 kN/m3
Answer
∴ The unit weight of hardened Plain Cement Concrete (P.C.C) cube is 24
kN/m3
16 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

17. The unit weight of some of the commonly used building and construction
materials are shown below.
0 20 40 60 80
Aluminium
Brick
Concrete
Glass
Limestone
Polystyrene Foam
Steel
Water
Wood (Pine)
Wood (Oak)
27
19.3
24
24.2
16.2
3 · 10−2
76.8
9.8
5
7.1
Unit Weight (in kN/m3
)
17 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

18. 3. Specific Gravity (or) Relative Density
Specific gravity Gs is defined as the “ratio of mass or weight of a
volume (density or unit weight) of the material to the mass or weight
of a volume (density or unit weight) of the reference material”.
Specific gravity is commonly referred to as ‘relative density’.
Generally, water is taken as the reference material whose density and
unit weight at 4o
C are 1000 kg/m3
and 9.8 kN/m3
respectively.
Gs =
γm
γw
=
ρm.¡g
ρw.¡g
=
ρm
ρw
γ = ρ.g (7)
Where,
Gs = Specific Gravity of the material (Constant)
γm = Unit weight of the material, in kN/m3
γw = Unit weight of the water, in kN/m3
ρm = Density of the material, in kg/m3
ρw = Density of the water, in kg/m3
g = Acceleration due to gravity, in m/s2
(g = 9.81 m/s2
on Earth)
18 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

19. 3. Specific Gravity (or) Relative Density (Cont...)
– Apparent Specific Gravity & Absolute Specific Gravity
Apparent Specific Gravity is defined as the ratio of mass or weight
including both intrinsic and extrinsic voids in a volume (density or
unit weight) of the material to the mass or weight (density or unit
weight) of equal volume of the reference material.
This is also referred to as ‘mass specific gravity’.
Absolute Specific Gravity is defined as the ratio of mass or weight
excluding voids in a volume (density or unit weight) of the material
to the mass or weight (density or unit weight) of equal volume of the
reference material.
This is also referred to as ‘true specific gravity’.
19 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

20. Example 4: Calculation of Apparent & Absolute Specific Gravity
Calculate the apparent and absolute specific gravity of mineral admixture
sample whose density at natural state (loose, dry) and when densified
(compacted, dry) is 1442 kg/m3
and 1922 kg/m3
respectively.
Solution: Given Data:-
Density of mineral admixture sample at natural state (loose, dry),
ρm(undensified) = 1442 kg/m3
Density of mineral admixture sample after densification (compacted, dry),
ρm(densified) = 1922 kg/m3
We know that, density of water at 4o
C, ρw = 1000 kg/m3
Apparent Specific Gravity =
ρm(undensified)
ρw
=
1442
1000
= 1.442 (Constant)
Absolute Specific Gravity =
ρm(densified)
ρw
=
1922
1000
= 1.922 (Constant)
20 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

21. The specific gravity of some of the commonly used building and
construction materials are shown below.
0 2 4 6 8
Aluminium
Brick
Concrete
Glass
Limestone
Polystyrene Foam
Steel
Water
Wood (Pine)
Wood (Oak)
2.78
1.97
2.4
2.47
1.65
3 · 10−2
7.83
1
0.51
0.72
Specific Gravity
21 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

22. Relative Volume Fraction
– Porosity, Compactness & Void Ratio
Porosity (p) is defined as the “ratio of volume of voids (ve) to the
apparent volume (V ) of the material”.
p =
ve
V
=
ve
vm + ve
(8)
Compactness (c) is defined as the “ratio of volume of material (vm)
(excluding, volume of voids) to the apparent volume (V ) of the
material”.
c =
vm
V
=
vm
vm + ve
(9)
=⇒ c =
vm
V
=
V − ve
V
=
V
V
−
ve
V
= 1 −
ve
V
= 1 − p
∴ c = (1 − p)
22 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

23. Relative Volume Fraction (Cont...)
– Porosity, Compactness & Void Ratio
Void Ratio (e) is defined as the “ratio of volume of voids (ve) to the
volume of the material (vm) (excluding, volume of voids)”.
e =
ve
vm
(10)
=⇒ e =
ve
vm
=
ve
V − ve
=
ve
ve ×
V
ve
− 1
e =
ve
ve ×
V
ve
− 1
=
1
1
p
− 1
=
1
1 − p
p
=
p
1 − p
∴ e =
p
(1 − p)
=
p
c
23 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I

24. Relative Volume Fraction (Cont...)
– Porosity, Compactness & Void Ratio
A relationships exists between these three quantities as shown in
Equation 10 and is also expressed as follows.
p =
ve
V
=
e × vm
V
= e ×
vm
V
= e × c
∴ p = e . c
Knowing of one of the quantities enables us to calculate the other
two quantities.
Porosity, compactness and void ratio are the three quantities that
characterize the relative volume fractions of voids and materials.
24 / 24 Ramesh Kannan, VIT Chennai CLE204 - Construction Materials and Technology - Unit I