CIVIL Ts. Dr Norhayati Binti Ngadiman Civil Engineering ...

Prepared by:

Ts. Dr Norhayati Binti NgadimanCivil Engineering Department

Center of Diploma StudiesUTHM

DAC 11603CIVIL

ENGINEERING MATERIALS

described as crushed stone, gravel, sand, slag

and recycled concrete, which is composed of

individual particles.

natural sources for aggregates include gravel

pits, river run deposits and rock quarries

Production

Methods

Petrological

Characteristics

Particle Size

Unit

weight

Shape

Igneous Rock Sedimentary Rock Metamorphic Rock

Definition

Rocks formed by

solidification of

cooled magma by

crystallizing into a

mosaic of materials

Rocks formed from

sediments of the

earth’s land area

Rocks are created by

changes induced at

high temperature

and/or high pressure

Igneous Rock Sedimentary Rock Metamorphic Rock

Environment Underground: and as

lava flows

Deposition basin:

mainly sea

Mostly deep inside

mountains chains

Rock strengthUniform high

strengthVariable low Variable high

Major types

with

compressive

strength

Granite (90 MPa),

basalt (160Mpa)

Sandstone (40Mpa),

limestone, claySchist, slate

Aggregate can be classified according to

their unit weight.

2.2.1 High-Density Aggregate (H-DA)

2.2.2 Light Weight Aggregate (LWA)

Bulk density is a property of particulate

materials.

the mass of particles of the material

divided by the volume they occupy.

volume includes the space between

particles as well as the space inside the

pores of individual particles

Specific gravity (SG) is a special case of

relative density defined as the ratio of

the density of a given substance, to the

density of water.

Substances with a specific gravity greater

than 1 are heavier than water, and those

with a specific gravity of less than 1 are

lighter than water.

Determine the specific gravity of high density

aggregate which the unit weight is 2900

kg/m3. (ρwater = 1000 kg/m3).

s.g = ρHDA / ρwater = 2900 kg/m3 / 1000 kg/m3 = 2.9

2.2.3 Normal Aggregate (NA)

2.2.3 Normal Aggregate (NA)

2.3.1 Strength

• Aggregate cannot transmit tensile force from one particle to

another, but very well in resisting compressive forces.

• Angular particles and rough aggregates can create better

interlocking system and tendency to resist forces from

developed friction

The strength of aggregate is measured by on

following tests:

✓ Aggregate crushing value

✓ Aggregate impact test

✓ Ten percent fines value

The crushing strength of aggregate cannot be tested with any

direct test. There are some indirect tests to inform us about

the crushing strength of aggregate

2.3.2 Hardness

❖ the ability of aggregates to resist the damaging

effect (wearing) of load or applied pressure.

❖ be tested by using abrasion test as described in

BS 812: Part 113: 1990 or ASTM C 131: C535.

❖ It is an important property of concrete in roads

and in floor surfaces subjected to heavy traffic.

The most frequently used test method is the Los

Angeles Abrasion Test.

2.3.2 Hardness

❖ Los Angeles Abrasion Test: The aggregate of specified

grading is placed in a cylindrical drum, mounted

horizontally. A charge of steel balls is added, and the drum

is rotated a specified number of revolutions. The tumbling

and dropping of the aggregate and the balls result in

abrasion and attrition of the aggregate. The resulting

grading should be compared with the standard limitations.

2.3.3 Durability

❖ the ability of aggregate to withstand external or internal

damaging attack such as weathering effect (also known as

soundness)

❖ the soundness of aggregate is tested by simulating the

weathering effect by soaking the different sized fractions

of oven-dry sample, in sodium sulfate or magnesium

sulfate solution for 16 hours to create freezing effect.

❖ The sample is subjected to five cycles of soaking and

drying procedure. Tested samples were then washed and

weighted to determine loss percentage of entire samples.

The results will be compared with allowable limits to

determine whether the aggregate is acceptable

2.3.4 Toughness

❖ the resistance if aggregate to failure by impact.

❖ can be determined by implementing Aggregate Impact Test

according to MS 30: Part 10: 1995.

❖ The aggregate impact value shall not exceed 45% by weight

for aggregate used in concrete and 30% for wearing

surface.

2.3.5 Porosity

❖ the ratio of the volume of pores in particle to its total

volume (solid volume Plus the volume of pores)

❖ Porosity of natural aggregate can be determined by using

following formula:

Type of Rock Porosity (%)

Granite

Shale

Clay

Sandstone (fractured)

Sand

Gravel

Limestone (cavernous)

Chalk

1

3

50

15

30

25

5

20

Calculate the porosity of the coarse aggregates if

the water absorption is 5.5% and the specific

gravity of the aggregates is 2.73.

( )( )

( )%23.14

5.5100

73.25.5100%

100

100=

+

=

+

=

W

GWPorosity s

Calculate the percentage of water absorption if

the porosity is 10 % and the specific gravity of the

aggregates is 2.5.

Calculate the percentage of water absorption if

the porosity is 10 % and the specific gravity of the

aggregates is 2.5.

Answer:

W = 4.17 %

Calculate the porosity of the coarse aggregates

if the water absorption is 4.5% and the specific

gravity of the aggregates is 2.92.

Calculate the porosity of the coarse aggregates

if the water absorption is 4.5% and the specific

gravity of the aggregates is 2.92.

( )( )

( )%57.12

5.4100

92.25.4100%

100

100=

+

=

+

=

W

GWPorosity s

2.3.6 Absorption

❖ Aggregate can capture fluid (water, moisture, asphalt

binder and etc) in surface voids. Voids represent the

amount of air space between the aggregate particles.

❖ The amount of void normally expressed as void content

and can be determined by using equation below:

Calculate the void content if given the value of

aggregates specific gravity is 2.75, density of

water is 1000kg/m3 and the bulk density of

aggregates taken as 1745 kg/m3.

𝑉𝑜𝑖𝑑 𝐶𝑜𝑛𝑡𝑒𝑛𝑡 =𝑆𝐺 𝑥 𝑊 −𝐵

𝑆𝐺 𝑥 𝑊𝑥 100 =

2.75 𝑥 1000 −1745

2.75 𝑥 1000𝑥 100 = 𝟑𝟔. 𝟓𝟓%

Calculate the void content of a sample of

aggregate based on the given data:

Specific gravity, SG = 2.63,

Density of water, W = 1000kg/m3,

Bulk density of aggregates, B = 1528kg/m3

Calculate the void content of a sample of

aggregate based on the given data:

Specific gravity, SG = 2.63,

Density of water, W = 1000kg/m3,

Bulk density of aggregates, B = 1528kg/m3

𝑉𝑜𝑖𝑑 𝐶𝑜𝑛𝑡𝑒𝑛𝑡 =𝑆𝐺 𝑥 𝑊 −𝐵

𝑆𝐺 𝑥 𝑊𝑥 100 =

2.63 𝑥 1000 −1528

2.63 𝑥 1000𝑥 100 = 𝟒𝟏. 𝟗𝟐%

2.3.6 Absorption

❖ absorption capacity or water absorption or absorbed

moisture can be defined as the moisture content in the

saturated surface dry condition.

(a)Bone Dry

(b)Air Dry

(c) SSD (semi-saturated dry)

(d)Moist

2.3.6 Absorption

2.3.6 Absorption

❖ Determination of moisture content (MC) can be calculated

by using following equation:

❖ method of determination of moisture content and

absorption of aggregate. They are:

Determine the moisture content of the sample

of fine aggregates if their weight in moist

condition found to be 4.52 kg (with tray) and

the dry weight after 24 hours in oven was 4.23

kg (with tray). The weight of the tray is 0.52

kg.

%82.710052.023.4

23.452.4

%100

=−

−=

=ghtovendrywei

istureweightofmoMC

Calculate the moisture content of the sample of

coarse aggregates if their weight in moist

condition found to be 8.65 kg (with tray) and the

dry weight after 24 hours in oven was 8.16 kg (with

tray). The weight of the tray is 1.5 kg.

%36.71005.116.8

16.865.8

%100

=−

−=

=ghtovendrywei

istureweightofmoMC

Sieve analysis is the name of the operation of

dividing a sample of aggregate into fractions,

each consisting of particles of the same size.

In practice each fraction contains particles

between specific limits, these being the

openings of standard test sieves.

Graphical representation (ordinates represent the

cumulative percentage passing and the abscissa the sieve

opening plotted to a logarithmic scale)

See at a glance whether the grading of a given sample

conforms to that specified or is too coarse or too fine.

Table 2.3: Typical Grading Curves for A Zone 2 Fine

Aggregate and A Graded 20 mm Coarse Aggregate

Table 2.2 Grading Limits for Fine Aggregate (Derived from BS 882)

Gap grading is a grading in which one or more

intermediate size fractions are omitted (limited

sizes, good interlock, low permeability)

Well Graded means sizes within the entire range

are in approximately equal amounts (friction at

many points, excellent interlocking, very few

voids or low permeability)

Uniform gradation means a large percentage of

the particles are of approximately the same

size (poor interlocking, high percentage of

voids, friction at few points of contact)

Combined gradation means fine and coarse aggregates

are combined (friction at many points, good interlocking,

few voids, economical).

The Fineness Modulus (FM) used to determine theaggregate distribution.

The lower the Fineness Modulus the smaller theaverage particle size and the larger the finenessmodulus the larger the average particle size.

Fineness modulus is the sum of the cumulative percentage

retained on the sieves of the standard test sieves. Fineness

modulus (FM) = (Cum. percent retained / 100)

Fine aggregate: 2.3-3.0

Coarse aggregate: 5.5-8.0

Combined aggregate: 4.0-7.0

Table A shows the result of sieve analysis on a sample of aggregates.

(i) Percent retained

(ii) Percent passing

(iii) Cumulative percent retained

(iv) Fine modulus

(15 marks)

.

SIEVE MASS RETAINED (g)

25mm (1 in) 0

20mm (3/4 in) 326.8

12.5mm (1/2 in) 1361.6

10mm (3/8 in) 1960.7

4.76mm (No. 4) 1412.0

2.38mm (No. 8) 276.4

1.19mm (No. 16) 75.1

Pan 63.0

TOTAL 5475.6

Table A shows the result of a sieve analysis

Therefore fine modulus = 392.5/100 = 3.925

Table B shows the result of sieve analysis on a sample of aggregates.

(i) Calculate the percent retain

(ii) Calculate the percent passing

(iii) Plot the size distribution curve

(10 marks)

.

SIEVE MASS RETAINED (g)

25 135

19 312

12.5 1310

9.5 1955

4.75 1407

2.3 255

1.18 62

Pan 49

Total 5485

Table B shows the result of a sieve analysis

Aggregate has three dimensional of masses namely shape,

size and surface texture.

external characteristic

Rough texture generally improves the bonding, inter-

particle friction but more difficult to compact into a dense

configuration.

measure of the smoothness or roughness of the aggregate.

The strength of the bond between aggregate and cement

paste depends upon the surface texture.

An aggregate with rough and porous texture may increase

the aggregate-cement bond up to 1.75 times, in which may

increase the compressive and flexural strength of concrete

up to 20%.

The surface pores help in the development of good bond

on account of suction of paste into these pores. Aggregate

with polished surface do not produce such strong concrete

compared to those with rough surface

2.6.1 Palm oil shell

2.6.2 Crushed burnt bricks

2.6.3 Natural LWA

2.6.4 Industrial by-product

2.6.5 Expanded palletized fly ash aggregates

palm oil shells as aggregates are similar to the lightweight

concrete produced using the more common aggregates such as

clinker, foamed slag and expanded clay.

palm oil shells are hard and are received as crushed pieces as a

result of the process used for extracting the oil.

contain a large amount of fine particles which are removed by

manual sieving.

the shells are air-dried before use

workability and compressive strength of lightweight concrete

with palm oil shells as aggregates is affected by the proportion

of palm oil shell and the water-to-cement ratio.

28 day cube compressive strengths of the lightweight concrete

vary between 5.0 to 19.5 MPa.

Particle distribution curve for palm oil shells and sand

use of crushed bricks or sintered clays as

aggregates were practiced since ancient

masonries

densities of these aggregates were in the

range of 1500 to 2000 kg/m3.

porous and resemble a sintered clay

aggregates.

Wet process – similar to preparing for clay for

brick production – is more usual for soft

clays.

Dry process – pelletizing or crushing is more

common for harder shales and for slates.

Burning and expanding – mostly done in

rotary kilns at the temperature of about

1100˚C to 1200˚C.

varying sizes and densities can be produced

for example; 8 to 16 mm and densities of 300

to 800 kg/m3.

Perlite mineral: a glassy material from

volcanic eruption with water content of 2 to

6 %.

crushing the material to graded sizes and

rapidly heating it to the point of incipient

fusion

Perlite which quickly heated to above 870˚C,

it expands and produces aggregates with a

bulk density of 30 to 240 kg/m3.

Consist of by product of a thermal power

station

The quality depends on the temperature and

heating rate.

Day and night production of fly ash gives

different carbon content and particle sizes.

High quality with low carbon content used as

concrete admixture while low quality with

high carbon content are used in landfilling

activities.

Pellet formation of fly ash aggregates