CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND OF STUDY

Concrete is an extraordinary and key structure material in the human history. As

written by Branaver and Copeland (1964), “Man consumes no material except

water in such tremendous quantities.” Concrete is a heterogeneous mix of

cement, aggregates and water. It is no doubt that with the development of

human civilization, concrete will continue to be a dominate construction

material.

The concrete industry is constantly looking for supplementary cementitous

material with the objective of reducing solid waste disposal problem and also

bring reduction in cost of construction.

Aluminium is one of the widely used construction material used in the world,

and during any aluminium smelting, huge amount of waste is produced. Among

the several waste is aluminium dross

Aluminium dross is mixture of metallic aluminium and non-metal part mostly

aluminium oxide and is a valuable by product of any aluminium smelter

The partial replacement of cement with aluminium dross in concrete production

is a welcome development especially in Nigeria.

1

Various research indicates that most material that are rich in amorphous silica

possesses cementitous properties and therefore sufficient enough in the partial

replacement of cement.

Cement partially mixed with aluminium dross forms a new binder which may

be useful economically and also result in a high performance concrete.

1.2 STATEMENT OF PROBLEM

The increase in cost and production of cement in Nigeria and also the

environmental pollution that may arise from the indiscriminate disposal of

aluminium dross.

1.3 AIMS AND OBJECTIVES OF STUDY

To determine the suitability of aluminium dross in use for partially replacement

of cement in concrete by conducting compressive and workability test.

To determine the optimum replacement ratio of cement with aluminium dross

that produces the best economically performing concrete with desired effects.

2

1.5 SIGNIFICANCE OF STUDY

The following significance are derived from the research

i. To promote use of aluminium dross economically in concrete production

which will also help in reduction of aluminium dross as a solid waste

ii. To reduce significantly cost of using cement in concrete production by

correct application of aluminium dross

1.6 SCOPE OF STUDY

i. Obtaining and preparation of sample(Aluminium dross)

ii. The use of the concrete mix for concrete tests to be carried out. This tests

include compressive and workability.

iii. Casting of concrete cubes using different proportional ratio of cement to

aluminium dross

iv. Curing and crushing of cubes after 7, 14 and 28days to determine their

strength

v. Obtaining the optimum level of partial replacement of cement with

aluminium dross

vi. Deriving conclusions and make recommendations with results

3

CHAPTER TWO

LITERATURE REVIEW

2.1 OVERVIEW

There are several studies that show the use of aluminium dross in construction

applications as the replacement of sand or cement, to produce concrete blocks,

to manufacture aluminates cement or as a filler in asphalt product. The results

proved that concrete products can be prepared by using aluminium dross as the

replacement of sand without causing deleterious effects on concrete

characteristics, and the calcium aluminates cement can be produced by using

aluminium dross as a source of CaO and Al2O3. (Puerto’s et al. (1999)It was

proved that the aluminium including high alumina may be used as raw materials

in cement production industry. Pereira et al. (2000) studied the effect of

aluminium dross on the mechanical properties of Portland cement mortar and

demonstrated that aluminium dross can be used as partial replacement material

for cement limits to obtain environmental and economic advantages was

studied. Borough (2007), recommend the potential use of aluminium dross as

filler in concrete. Another study based on using new industrial waste streams as

secondary aggregates demonstrated that white and black aluminium dross have

potential as filler aggregates in concrete production when it is in processed

form(<700um) (Dunster 2005).

4

Further, aluminium dross and aluminium sludge was used as sources of CaO

and Al2O3, respectively in production of calcium aluminates cement mixes

(Ewais et al. 2009). The effect of aluminium dross on the setting time, flexural

strength, and compressive strength of concrete has been studied and suggested

to use as a retarder for hot weather concreting (Elinwa 2011). Another study

showed that the use of aluminium dross manufactured from refractory material

increases the mechanical properties of concrete when it is used as filler (Chan

Dai 2012). However in this project we use aluminium dross obtained from

smelting procedure as partial replacement of cement in order to see the effects

on the compressive strength, workability.

Although some research has been done on the use of aluminium dross and its

use in concrete, very few studies have examined the use of ground aluminium

dross replacing partially with cement in concrete production.

The construction industry relies heavily on cement for its operation in the

development of shelter and other infrastructural facilities. It then becomes

extremely difficult for majority of people to own their own houses or many

collapse structure in attempt to reduce cost. A way out of this is by either

reducing the energy costs in the burning of clinker or by increasing the

production of composite cement. The later involves replacing a proportion if the

clinker-high calorie consuming portion with other products that are suitable and

do not require further heat treatment.

5

2.2 CONCRETE

2.2.1 HISTORY OF CONCRETE

Concrete is a building material composed of cement, crushed rock or gravel,

sand and water, often with chemical admixtures and other materials. It was

known to the Romans, the Egyptians and to earlier Neolithic civilization. After

the collapse of the Roman Empire its secrets were almost lost, only to be

discovered in more recent times. Indeed, modern development spans more than

175 years, 1824 is the patent for the manufacture of the first Portland cement,

one of the most important milestone in the concrete industry.

There have been remarkable developments in the last few decades of the 20 th

century, with new structures, new techniques for handling concrete and even

new kinds of concrete. Since the middle of the 19 th century great rivers have

been spanned, huge buildings erected, vast sheets of water dammed and large

networks of roads construction. In these and a thousand other ways the face of

the world has been changed as a result of the discovery of concrete and the

many ways to which it can be put. Concrete has also played a major role in the

improving the health of the world’s inhabitants through its use for sewage

disposal and treatment and for dams and pipes providing clean water for

drinking and washing.

6

The oldest concrete so far discovered dates from 700BC and was found in 1985

when a bulldozer uncovered a concrete floor during construction of a road near

Yiftah el in southern Galilee, Israel .It consists of lime concrete, made from

burning limestone to produce quicklime, which when mixed with water and

stone set to form an early concrete. The floor varies in thickness from 30 to

80mm and was laid on an even base of sandy clay. The concrete has been well

compacted and its surface is hard and very smooth. The quantity of lime needed

for the 180mm2 floor would have required an effective lime kiln and fragments

of what was probably a kiln lining have been found at the site.

The earliest known illustration of concrete work can be seen in a mural from

Thebes in Egypt dating from about 1950BC that shows various stages in the

manufacture and use of mortar and concrete. For many years concrete was just

used as an infill material for stone walls and only much later did it develop as a

structural material in its own right. The art of making concrete eventually

spread from Egypt around the eastern Mediterranean and by 500bc was being

used in ancient Greece.

The Greeks used time based compositions to cover walls of sun dried bricks. It

is reported that the palace of Croesus and AL talus were built in this way. It was

also used as a render for the porous limestone used in templis, and as a binding

material between brick and stone.

7

Sometime during the second century BC the Romans quarried pink volcanic ash

from near Pozzuoli. Thinking it was sand, they mixed it with lime and found

that the mixture resulted in a much stronger concrete than anything they had

previously produced.

This discovery was to have a far reaching effect in the building and civil

engineering during the next four hundred years, for the material was not sand,

but a fine volcanic ash containing silica and alumina which combined

chemically with lime to produce what became known as pozzolanic cement.

The Romans were versatile and enterprising engineers and used concrete

extensively in the foundations of their harbours and bridges. Their aqueducts,

reservoirs, and sewers were lined with it, and they even made pre-cast concrete

blocks for use underwater. One of these aqueducts at Ponte Gard near Nimes in

southern France.

A great milestone in the history of concrete was the invention of Portland

cement by Joseph Aspdin. The cement making process was improved by Isaac

Johnson who managed a cement work. He raised the temperature at which the

cement was fired, and is regarded as the father of modern Portland cement.

The very first all-concrete was built for John Bazley while at Swanscombe,

Kent, in 1835. It had concrete walls, tiles, window frames and decorative work

and even concrete gnomes in the garden. It lacked a floor of concrete. As early

8

as 1830 the idea of reinforced concrete was first mentioned in the encyclopaedia

of cottage, farm and village architecture which suggested that an iron rods could

be embedded in concrete. In 1848 the world’s first reinforced concrete was built

in France by Jean Louis lambert.

2.2.2 CONCRETE AT AGE

The late 1960s saw a continuation of the need to cater for the post war “baby

boon” and concrete played a major part in accommodating the influx of students

to universities and colleges.

A major factor over the years has been the increase in the strength of concrete

and this has influenced design by allowing taller, longer, and yet lighter

structures. The emphasis has now switched to durability issues, and the concept

of whole life costing, that is the construction cost of the structure plus its cost in

use. This has resulted in the increased importance being given to the cost of

repair, the energy used and projected years of service.

2.2.3 DEFINITION OF CONCRETE

Concrete is the mostly widely used construction material in the world. It is used

in many different structure such as dam, pavement, buildings or bridge. Also it

is the most widely used material in the world far exceeding other material. The

present consumption of concrete is over 10 billion ton a year, that is each per on

earth consumes more than 1.7ton concrete per year.

9

Concrete is a composite material composed of coarse granular material (the

aggregate or filler) embedded in a hard matrix of material (the cement or

binder) that fills the space between the aggregates particles and glues them

together. The simplest representation of concrete is

Concrete= Filler + Binder

According to the type of binder used there are different kinds of concrete. For

instance Portland concrete, asphalt concrete and epoxy concrete.

In concrete construction, the Portland cement concrete is utilized the most. For

this kind of concrete, the composition can be represented as follows

Cement (+ Admixtures) + Water

Cement Paste + Fine Aggregates

Mortar + Coarse Aggregates

Concrete

2.2.4 ADVANTAGES AND LIMITATIONS OF CONCRETE

Concrete is the most widely used construction material in the world. It is used in

many different structures such as dam, pavement, building frame or bridge.

Also, it is the most widely used material in the world, far exceeding other

materials. Its worldwide production exceeds that of steel by a factor of 10 in

tonnage and by more than a factor of 30 in volume. The present consumption of

10

concrete is over 10 billion tons a year, that is, each person on earth consumes

more than 1.7 ton of concrete per year. It is more than 10 times of the

consumption by weight of steel.

2.2.4.1 ADVANTAGES:

a. Economical: Concrete is the most inexpensive and the most readily

available material. The cost of production of concrete is low compared

with other engineered construction materials. Three major components:

water, aggregate and cement. Comparing with steel, plastic and polymer,

they are the most inexpensive materials and available in every corner of

the world. This enables concrete to be locally produced anywhere in the

world, thus avoiding the transportation costs necessary for most other

materials.

b. Ambient temperature hardened material: Because cement is a low

temperature bonded inorganic material and its reaction occurs at room

temperature, concrete can gain its strength at ambient temperature.

c. Ability to be cast: It can be formed into different desired shape and sizes

right at the construction site.

d. Energy efficiency: Low energy consumption for production, compare

with steel especially. The energy content of plain concrete is 450-750

kWh / ton and that of reinforced concrete is 800-3200 kWh/ton,

compared with 8000 kWh/ton for structural steel.

11

e. Excellent resistance to water. Unlike wood and steel, concrete can

harden in water and can withstand the action of water without serious

deterioration. This makes concrete an ideal material for building

structures to control, store, and transport water. Examples include

pipelines (such as the Central Arizona Project, which provide water from

Colorado River to central Arizona. The system contains 1560 pipe

sections, each 6.7 m long and 7.5 m in outside diameter 6.4 m inside

diameter), dams, and submarine structures. Contrary to popular belief,

pure water is not deleterious to concrete, even to reinforced concrete: it is

the chemicals dissolved in water, such as chlorides, sulphates, and carbon

dioxide, which cause deterioration of concrete structures.

f. High temperature resistance: Concrete conducts heat slowly and is able

to store considerable quantities of heat from the environment (can stand

6-8 hours in fire) and thus can be used as protective coating for steel

structure.

g. Ability to consume waste: Many industrial wastes can be recycled as a

substitute for cement or aggregate. Examples are fly ash, ground tire and

slag.

h. Ability to work with reinforcing steel: Concrete and steel possess

similar coefficient of thermal expansion (steel 1.2 x 10 -5; concrete 1.0-1.5

x 10-5).

12

2.2.4.2 LIMITATIONS:

a. Quasi-brittle failure mode: Concrete is a type of quasi-brittle material.

(Solution: Reinforced concrete)

b. Low tensile strength: About 1/10 of its compressive strength.

(Improvements: Fibre reinforced concrete; polymer concrete)

c. Low toughness: The ability to absorb energy is low. (Improvements:

Fibre reinforced concrete)

d. Low strength/BSG ratio (specific strength): Steel (300-600)/7.8.

Normal concrete (35-60)/2.3. Limited to middle-rise buildings.

(Improvements: Lightweight concrete; high strength concrete)

e. Formwork is needed: Formwork fabrication is labour intensive and time

consuming, hence costly (Improvement: Precast concrete)

f. Long curing time: Full strength development needs a month.

(Improvements: Steam curing)

g. Working with cracks: Most reinforced concrete structures have cracks

under service load. (Improvements: Pre-stressed concrete).

2.2.5 PROPERTIES OF CONCRETE

The properties of concrete is grouped under

13

2.2.5.1 FRESH CONCRETE

Fresh concrete is concrete at the state when its component is fully mixed, it is

not yet hardened, and its strength has not yet developed. The properties of fresh

concrete directly influence the handling, placing and consolidation as well as

the properties of hardened concrete. Properties of fresh concrete include

a. Workability: This refers to the ease with which concrete can be

transported, placed, consolidated. Or the amount of mechanical work

required for full compaction of the concrete without segregation. The

primary characteristics of workability are consistency or fluidly and

cohesiveness. While consistency is used to measure the ease of floe of

fresh concrete, cohesiveness is used to describe the ability of fresh

concrete to hold all ingredients together without segregation and

excessive bleeding.

Measurement of workability include

Slump test (BS 1881; 102 replaced by BS EN 12350-2)

Compaction test (BS 1881: part 103)

Vebe test (BS 1881: part 104)

i. Slump Test: Three different types of possible slumps exists, they

are true slump, shear slump, and collapse slump. Conventionally

when shear or collapse slump occur, the test is considered invalid. 14

However due to recent development, the term of collapse slump

has to be used with caution

ii. Compaction Factor Test: This was developed in Great Britain in

1947. The upper hopper is completely filled with concrete which is

then successively dropped into the lower hopper and then into the

cylindrical mould. The excess of concrete is struck off and the

compacting factor is defined as the weight ratio of the concrete in

the cylinder, mp, to the same concrete carefully compacted in the

cylinder filled in four layers and tamper or vibrated, mf(i.e.

compacting factor =mp/mf). For the normal range of concrete the

compacting factor lies 0.8 to 0.92(values less than 0.7 or higher

than 0.92 is regarded as unsuitable. This test is good for very dry

mixes, and its limitation is

It’s not suitable for field application

Not consistent

Mixes can stick to the sides of the hopper

iii. Vebe test (BS 1881: Part 104):

The Vebe consist meter was developed in 1940 and is probably the

most suitable test for determining differences in consistency of very

dry mixes. This test method is widely used in Europe and is described

15

in BS 1881: Part 104. It is, however, only applicable to concrete with

a maximum size of aggregate of less than 40 mm. For the test, a

standard cone is cast. The mould is removed, and a transparent disk is

placed on the top of the cone. Then it is vibrated at a controlled

frequency and amplitude until the lower surface of the disk is

completely covered with grout. The time in seconds for this to occur is

the Vebe time. The test is probably most suitable for concrete with

Vebe times of 5 to 30s. The only difficulty is that mortar may not wet

the disc in a uniform manner, and it may be difficult to pick out the

end point of the test.

Factors Influencing the Workability of Concrete

The factor which can influence the workability of concrete are water content,

cement content, aggregate grading, aggregate characteristics (i.e. maximum

size, shape, and texture), amount of entrain air, chemical admixture and

cementitious material(e.g. Fly ash, GGBS and CSF)(Neville, 1995; Mehta and

Monteiro; 1993). The following are most influencing factor

Water Content: Water content of the mix expressed in kilogram or litres of

water per cubic meter of concrete is the main factor affecting workability. It is

assumed that for a given maximum size of coarse aggregate, the workability of

concrete is direct function of the water content (Falade, 1994; Hobbs, 1993;

Poporis 1962). It also has be confirmed by Figg (1992) in that a relatively small 16

increase in water content can cause a sudden increase in workability of fresh

concrete.

Cement content: Lowering the cement content of concrete with

given water content, will lower the workability. A high proportion

of cement will result in excellent cohesiveness but may be too

sticky to be finished conveniently (Mehta and Monteiro, 1993).

Temperature and time: As temperature increases workability

decreases, also workability decreases with time. These effects are

related to the progression of the chemicals.

2.2.5.2 HARDENED CONCRETE

Properties of hardened concrete include

Strength: This is defined as the ability of a material in this concrete to

resist stress without failure. The failure of concrete is due to cracking.

Compressive Strength: The compressive strength of concrete is the

most common performance measure used by the engineer in designing

buildings and other concrete structures. The compressive strength is

measured by breaking cubed/cylindrical concrete specimen in

universal testing machine. The Compressive strength is calculated

from the failure load divided by the cross sectional area resisting the

17

load. Concrete compressive strength requirement can vary from

17MPa to 28MPa.

A 28-day compressive strength of concrete determined by a standard uniaxial

compression test is accepted universally. Concrete may be classified based on

strength

Low-Strength Concrete <20MPa

Moderate-Strength Concrete 20MPa-50MPa

High-Strength Concrete 50MPa-200MPa

Ultra-Strength Concrete >200MPa

Flexural Strength: Flexural strength is one measure of the tensile

strength of concrete. It is a measure of an unreinforced concrete beam

or slab to resist failure in bending. It is measured by loading 6x6inch

(150mmX150mm) concrete beams with span length at least three

times the depth. The flexural strength is expressed as Modulus of

rupture (MR) in psi (MPa) and is determined by standard test

methods. Flexural strength is about 10 to 20 Percent of the

compressive strength depending on the type, size, and volume of

coarse aggregate used. Sometimes the compressive strength test is

18

convenient and reliable to judge the quality of concrete, therefore

some agencies don’t require flexural strength test.

Tensile Strength: the development of tensile strength is similar to that

of compressive strength and is influenced by same factors

(Temperature, humidity, replacement level, compaction)

ii.Durability: Durability of concrete is the ability of concrete to resist

weathering action, chemical attack, abrasion, or any process of deteriorate and

hence to retain its original shape, dimension, quality and serviceability.

2.2.6 STRUCTURE OF CONCRETE

Concrete has highly heterogeneous and complex structure, which makes it very

difficult to constitute exact models of the concrete structure. At the

microstructure level, concrete can be regarded consisting of two phases i.e.

aggregate phase and binding medium phase (usually hydrated cement paste)

(Neville, 1995a; Powers, 1958). However at microstructure level a third phase,

the transition zone or interfacial transition zone is recognized, which represents

the interfacial region between the particles of the coarse aggregate and the

hydrated cement paste (Mehta and Monteiro, 1993). Structure of concrete has a

direct influence in the strength and durability properties of concrete.

19

2.2.7 CONCRETE MIX DESIGN

Mix design is a process by which one arrives at the right combination of

cement, aggregate, water and admixture to produce concrete to satisfy given

specifications.

The main purpose of mix design is to obtain a product that will perform

according to predetermined requirement. They include

Quality (Strength and durability)

Workability

Economy

Information required for concrete mix design

a. Grade of Concrete (characteristic strength)

b. Workability requirement in terms of slump

c. Ascertain whether condition exposure to concrete is mild, moderate,

severe, or very severe. Proper Investigation of soil should be done to

ascertain presence of sulphates or chloride in case of doubt

d. Other Properties(If required)

i. Retardation of initial set

ii. Slump retention

20

iii. Pump ability

iv. Accelerating of strength

v. Flexural strength

e. Degree of control on site

i. Batching- Weight batching or Volume batching

ii. Types of aggregate

iii. Testing of concrete

iv. Source of aggregate

v. Supervision

vi. Site laboratory

Decision Variables in mix design

Water/cement ration

Cement content

Relative proportion of the fine and coarse aggregate

Use of admixtures

21

2.2.7.1 METHODS OF MIX DESIGN: The basic objective of concrete

mix design is to find the most economical proportion to achieve the desired

results (strength, cohesion, workability, durability). The code of practice used

for mix design is IS-10262.

Basic steps to mix design are as follows

Find the target mean strength

Determine the curve of cement based in its strength

Determine the water cement ratio

Determine the cement content

Determine fine and coarse aggregate proportion

2.2.8 CURING OF CONCRETE

Curing is maintaining of an adequate moisture content and temperature in

concrete at early ages so that it can develop properties the mixture was designed

to achieve. Curing begins immediately after placement and finishing so that the

concrete may develop the desired strength and durability.

Without an adequate supply of moisture, the cementitous material in concrete

cement react to form a quality product. Drying may remove the water needed

for the chemical reaction called hydration and the concrete will not achieve the

potential properties.

22

The need for adequate curing of concrete cannot be over emphasized. Curing

has a strong influence in the properties of hardened concrete. Proper curing will

increase durability, strength, water tightness, abrasion resistance, volume

stability and resistance to freezing and thawing.

2.2.8.1 METHODS AND MATERIAL OF CURING

Concrete can be kept moist and in some cases at a favourable temperature by

three curing methods

a. Methods that maintain the presence of mixing water in the concrete

during early hardening period. These include ponding and immersion,

spraying or fogging and saturated wet coverings. These methods afford

some cooling through evaporation which is beneficial in hot weather.

b. Methods that reduce the loss of mixing water from the surface of the

concrete. This can be done by covering the concrete with impervious

paper or plastic sheets, or by applying membrane forming curing

compounds.

c. Methods that accelerate strength gain by supplying heat and additional

moisture to the concrete. This is usually accomplished with live steam,

heating coils, or electrical heater.

23

Of all, the most thorough method of curing with water consists of total

immersion of the finished concrete methods. This method is commonly used in

laboratory for curing concrete test specimens.

2.2.9 COMPONENTS OF CONCRETE

2.2.9.1 CEMENT

A cement is a binder, a substance that sets and hardens and can bind other

materials together. Cement used in construction can be characterized as being

either hydraulic or non-hydraulic depending upon the ability of the cement to be

used in the presence of cement.

There are two major groups of cement. They are Hydraulic and non-hydraulic

cement. A hydraulic cement is capable of setting, hardening and remaining

stable under water. It consists essentially of hydraulic calcium silicate, usually

calcium sulphate e.g. Portland cement.

2.2.9.1.1 PORTLAND CEMENT

The name Portland cement comes from the fact that the colour and quality of

the resulting concrete are similar to Portland stone, a kind of limestone found in

England.

Manufacture of Portland cement

24

Portland cement is made by blending the appropriate mixture of limestone and

clay or together and by heating them at 1450oC in rotary kiln

The raw materials used for manufacturing Portland cement are limestone, clay

and iron ore

a. Limestone (CaCO3) is mainly providing calcium in the form of calcium

oxide (CaO)

CaCO3 (1000oC) === CaO + CO2

b. Clay is mainly providing silicate(sio2) together with small amounts of

Al2O3 + Fe2O3

Clay (1450oC) SiO2 + Al2O3 + Fe2O3 + H2O

c. Iron ore and bauxite are providing additional aluminium and iron oxide

(Fe2O3) which help the formation of calcium silicates at low temperature.

They are incorporated into the raw mix

Limestone 3CaOSiO2

Clay 2CaOSiO2

Iron ore, Bauxite 3CaOAl2O3

4CaO Al2O3 Fe2O3

d. The clinker is pulverized to small sizes (<75um), 35% gypsum (calcium

sulphate) is added to control setting and hardening.25

Types of Portland cement

According to ASTM standard there are five basic types of Portland cement

Type I Regular cement, general use called OPC

Type II Moderate sulphate resistance, moderate heat of hydration, C3A

<7%

Type III With increased amount C3S3 high early strength

Type IV Low heat

Type V High sulphate resistance

Table 2.1 Types of Cement and their constituent

I II III IV V

C3S 50 45 60 25 40

C2S 25 30 15 50 40

C3A 12 7 10 3 4

C4AF 8 12 8 12 10

CSH2 5 5 5 4 4

Fineness(m2/kg) 350 350 400 300 350

26

Compressive

strength 1day (Mpa)

7 6 14 3 6

Hydration Heat 330 250 500 210 250

2.2.9.2 AGGREGATES

The Importance of using the right type and quality of aggregates cannot be over

emphasized. The fine and coarse aggregates generally occupy 60% to 75% of

the concrete volume, 70% to 85% by mass and strongly influence the concrete

freshly mixed and hardened properties, mixture proportions and economy. Fine

aggregates generally consist of natural sand or crushed stone with most particles

smaller than 5mm.Coarse aggregates consist of one or a combination of gravel,

or crushed stone particles predominately larger than 5mm and generally

between 9.5mm and 57.5mm.

Aggregates must conform to certain standards for optimum engineering use.

They must be clean, hard, strong, durable particles free of absorbed chemicals,

coatings of clay and other fine materials in amounts that could affect hydration

and bond of the cement paste.

Classification of aggregates

27

According to particle size and source aggregates can be divided into the

following different categories

1. In accordance with size

a. Coarse aggregate: Aggregate mainly retained in 5.0mm BS test sieve

and containing no more finer material than is permitted according to

BS 882: 1992

b. Fine aggregate(Sand): Aggregated mainly passing 5.0mm BS test

sieve and containing no more coarser material than is permitted for the

various grading according to BS 882: 1992

2. In accordance with sources

a. Natural aggregate: The material is not changed artificially during

aggregates production although the aggregate itself may be submitted

to manufacturing process such as crushing, washing and sieving and

so on. Some examples are sand, gravel and crushed limestone.

b. Artificial aggregate: The material of the aggregate particles is

produced often as a by-product or waste, or by certain manufacturing

processes from naturally occurring materials. A typical example for

this type is crushed blast-furnace slag and artificial lightweight

aggregate. The most commonly used artificial lightweight aggregate is

Lytag, which is produced by pyro-processing. The Lytag particles are

28

spherical in shape and are of brown colour with an internal black core

(Swamy and Lambert, 1984)

Properties of Aggregates

Properties of the aggregates which influence the properties of both the fresh and

the hardened concretes are mainly the particle size distribution, the maximum

size of the particles and the shape and surface texture of the particles.

Furthermore the density and porosity together with water absorption and

moisture content have to be considered when the concrete is prepared.

Properties of aggregates which are relevant to this investigation are described in

the following section.

Particle shape

The shape of aggregate can be rounded, flaky, irregular, angular, and elongated.

Surface Texture

The surface texture of aggregates is classified as glassy, smooth, granular,

rough, and crystalline. Smooth aggregate need less water to achieve the same

workability as rough aggregates. Nevertheless rough surface of aggregate is

responsible for better mechanical bond in the hardened concrete, so strength is

comparatively higher that is if concrete with the same water/cement is used.

Specific gravity

29

The specific gravity of aggregates is determined for the saturated and surface

dry condition. This is defined as the ratio of the mass of the saturated and

surface dry aggregates to the mass of the equal volume of water.

Grading of Aggregate

The grading of an aggregate defines the proportion of particles of different

sizes. It is determined from a sieve analysis by following BS 882: Part 103.

2.2.9.3 WATER

Water plays two role in the production of concrete, which are as mixing water

and curing water (Popovics, 1992). The mixing water is the free water present

or freshly mixed concrete. It has three main functions

a. It reacts with the cement powder thus producing hydration

b. It acts as a lubricant contributing to the workability of the fresh mixture

c. It secures the necessary space in the paste for the development of

hydration products.

The amount of water needed for adequate workability is practically always

greater than that needed for complete hydration of the cement. Usually if the

water is portable, then it’s also suitable in the making of concrete.

30

2.3 ALUMINIUM

Aluminium occurs naturally as mineral bauxite (Primary mixture of

Al2O3.3H2O, Fe2O3 and sio4). It is one of the most plentiful element known to

man.

It was in 1808 that Sir Humphey Davy, the British electro chemist established

the existence of aluminium. The next step was its determination of specific

gravity and its characteristics was established. It was discovered that aluminium

is easy to shape, and could be melted with a blow torch.

The first aluminium to be produced commercially in New Zealand was at the

New Zealand aluminium smelter Ltd plant at tiwai point, southland in April

1971.

Constant research and product development throughout the1950s, 60s and 70s

led to endless range of consumer goods incorporating aluminium. Its basic

benefits of lightness, strength, durability, formability, conductivity and finish

ability made it much sought after product.

The necessity for the industry itself to pioneer the use of aluminium led to an

integrated structure in the major companies from the mining bauxite, in some

cases, the finished consumer product. As the world population soared, countries

with raw materials and especially those with cheap energy sources, began to

31

enter the market with primary making of aluminium, with others to further the

process.

2.3.1 PROPERTIES OF ALUMINIUM

Aluminium is a lightweight, durable metal. It is silvery appearance when freshly

cut, is a good conductor of heat and electricity and is easily shaped. Aluminium

has two main disadvantages when compared with other metals, firstly it has low

density about one third that of iron and copper .Secondly, although it reacts

rapidly with the oxygen in air, it forms a thin tough and impervious oxide layer

which resists further oxidation.

2.3.2 USES OF ALUMINIUM

These properties leads to a variety of specialized uses

a. LIGHTNESS: Used by aerospace and transport industries, as its

lightness enables a greater volume of metal to be used, thus giving greater

rigidity. Also used in pistons, connecting rods etc. to give better balance,

reduced friction and lower bearing loads, meaning that less energy is

required to overcome inertia.

b. THERMAL CONDUCTIVITY: used in cooking utensils.

c. CORROSION RESISTANCE: This is made use of in chemical plant,

food industry packaging, building and marine application. Aluminium

32

paint is widely used. The oxide film can be thickened by anodising and

the film can be dyed in a wide range of colours.

d. AFFINITY FOR OXYGEN: This allow it to be used as a de oxidation

in steels, in thermic reactions for welding and for the manufacture of

hardener alloys such a Ferro-titanium

e. DURABILITY: Aluminium is tough enough to withstand both effect of

space flight and challenging climatic conditions.

f. RECYCLABILITY: Once manufactured, aluminium can be recycled

repeatedly using only 5% of energy and generating 5% of the emissions

associated with primary production.

2.3.3 PRODUCTION PROCESS OF ALUMINIUM

Aluminium can be produced from either of the following method

2.3.3.1 PRIMARY ALUMINIUM PROCESS OR SMELTING

In 1886, Charles Martin Hall of Oberlin, and Paul Heroult of France, who were

both 22years old at the time, independently discovered and patented the process

in which aluminium oxide is dissolved in molten Cryolite and decomposed

electrolytic. The Hall-Heroult process remain the only method by which

aluminium metal is produced commercially.

33

The first step in the commercial production of aluminium is the separation of

aluminium oxide from iron oxide in bauxite. This is accomplished by dissolving

the aluminium oxide in concentrated sodium hydroxide solution. Aluminium

ions forms soluble complex ion with hydroxide ions while iron ions don’t.

Al2O3.xH2O(s)+2OH-(aq) 2Al(OH)4(aq) +(x-3)H2O(l)

After the soluble iron oxide is filtered from the solution Al(OH)3 is precipated

from the solution by adding acid to lower the pH to about 6. Then precipate is

heated to produce dry Al2O3 (Alumina)

2Al(OH)3(s) - Al2O3(s) + 3H2O(g)

In the Hall-Heroult process, aluminium metal is obtained by electrolytic

reduction of alumina. Pure aluminium melts at 2000oC. To produce electrolyte

at lower temperature alumina is dissolved in molten Cryolite 1000oC. The

electrolyte is placed in an inn vat lined with graphite. The vat serves as the

cathode. Carbon anodes are inserted into the electrolyte from the top. The

oxygen produced at the anodes react with them, forming carbon dioxide and

carbon monoxide. Molten aluminium metals is produced at the cathode and it

sinks to the bottom of the vat.

At interval, a plug is removed from the vat and the molten aluminium is

drained. The heat required to keep the mixture molten is provided by resistive

heating of the electrolyte by the current passing through the cell.

34

Solid waste from the aluminium smelting process include dross, unused carbon,

non-dissolved alumina, and spent pot liners.

2.3.3.2 SECONDARY ALUMINIUM PRODUCTION

This form of aluminium production used scrap as a raw material. After the scrap

is collected, it is sorted and cleaned before it is used in metal production. Scrap

sorting involves separating aluminium from other materials and by the different

alloys forms. Scrap cleaning involves the removal of oil, grease, and other

contaminant.

The core of secondary aluminium production is the melting and casting process.

The scrap is feed into melting furnaces to liquefy the metal. It is then purified,

adjusted to the desired alloy into a form suitable for subsequent

processing/fabrication. The kind of furnace involved in scrap melting include

rotary and electric furnaces.

Solid waste from secondary aluminium production facilities is mainly in the

form of salt cake used in flux.

2.4 ALUMINIUM DROSS

Aluminium dross is a by-product of aluminium production. It represents a

residue from primary and secondary aluminium production. Today much energy

is consumed to recover the aluminium from dross, energy could be saved if the

dross was diverted and utilized as an engineering material. There are two forms

35

of aluminium – white dross and black dross. White dross is formed during the

primary aluminium process while black dross is formed during the secondary

refining process, which uses relatively large amounts of chloride salt fixes.

Subsequently the dross is processed in rotary to recover the aluminium and the

resultant salt cake is sent to landfill.

There is much merit if the aluminium dross that is formed could be used as an

engineering product for specific applications. The driving force to use an

industrial waste such as aluminium dross and to use it as an engineering

material is not only an issue environmental, but also an economic one.

2.4.1 FORMATION OF ALUMINIUM DROSS

The products generated from aluminium melting furnaces fall into three

categories

Molten aluminium

Off gases i.e. CO2, SO2 and fluorides

Semi-solid mixture or aluminium dross

Aluminium dross can be divided into two types. Typically white dross which

has high metal content and Al2O3, produced from aluminium smelter process,

and black dross containing high oxides and salts, produced from secondary

aluminium production.

36

2.4.2 PHYSICAL AND CHEMICAL PROPERTIES

Table 2.2 Physical and chemical properties

Properties Black Dross White Dross

Alloy Content (%)

Metal

Recovered Metal

2.44-11.77

1.03-5.51

1.34-10.03

0.33-6.80

Distribution (q)(mm-1) 0.08coarse-0.492fine ----

Density(t/m3) 0.828-1.118(bulk) 2.396-2.528(apparent)

Metal Content (%) 46.9-69.1 71-93

Lixinate (pH) 9.52-10.14 9.03-9.48

Salt Content (%) 0.18-6.25 0.01-0.03

Gas Evolution(/Kg

Dross)

0.25-1.17 No evolution

JDD/SMG/AJC/EPSR/DTI “The physical and chemical reclamation and

recycling elements from black and white aluminium furnace residual”, progress

report NO 12, June 2002.

37

2.4.3 ENVIRONMENTAL ISSUES OF ALUMINIUM DROSS

There are potentially very serious environmental and health risks associated

with disposal of aluminium in disposing. Waste dumped in the past has leached

into the groundwater and eventually into drinking water, reserves, posing threat

to future generations. There is a link between the ingestion of certain heavy

metals (held most prominently within white dross) and serious deleterious

effects to health.

Once a pollutant reaches the soil a number of events may occur. The soil may

break down or be neutralized, pollutants may be washed out by rain (causing

water pollution) or evaporate (causing air pollution) in form of gas, or may

remain in the soil building up to high concentration successive additions.

38

CHAPTER THREE

MATERIALS AND METHODOLOGY

3.1. DESIGN OF THE RESEARCH

In this chapter, all the methods used in data collection and experiment, which

are useful for the research work “Effects of Partial Replacement of Cement with

Aluminium Dross in Concrete Production”, are dealt with.

3.2 MATERIAL PREPARATION

1.The Fine aggregate is sourced locally, passing 5mm sieve according to BS

882 (1992).

2.Aluminium dross collected from Aluminium Extrusion Industries (ALEX)

PLC, KM 4 Atta Amaimo, Inyshi, Imo State .Aluminium dross is black in

colour, irregular in shape.

3.Coarse aggregate of 20mm nominal size according to BS 882 (1992).

4.Ordinary Portland cement conforming to BS 12-EN 196 1996 (42.5R Class)

was used. The cement is well protected from dampness to avoid lumps.

5.Drinkable tap water supplied by Federal Polytechnic Nekede Owerri borehole

water supply, is used throughout the research experiments.

The tests is carried out at the Concrete Technology Laboratory of Federal

Polytechnic Nekede Owerri Imo state.

39

The materials is air dried. The coarse aggregate (granite chippings) passes

through sets of sieves, the portion passing retained on sieve (20mm) was used.

All tests is conducted according to the relevant British Standard (BS).

This study, “Effects of Partial Replacement of Cement with Aluminium Dross

in Concrete Production” is done to fulfil the objectives of this research which is

to determine the suitability and optimum replacement ratio.

3.3 APPARATUS AND INSTRUMENT USED

1. 150mm x 150mm Mould (Conforming to BS EN 12390-1)

2. Weighing Balance

3. Spade

4. Trowel

5. Spanner

6. Pinches

7. Set of Sieve

8. Weighing pan

9. Head pan

10. Bucket

11. Compacting rod (Conforming to Mould BS EN 12390-2)

12. Rule

13. Slump cone (Conforming to BS EN 12350-2)

14. Curing Tank

40

15. Universal Compressive Machine.

16. 150um Sieve

Figure 3.1:Universal crushing machine.

Figure 3.2: Weighing balance. Figure 3.3: Concrete mould.

3.4 SAMPLE AND SAMPLING TECHNIQUES

The batching quantity used is batching by weight (i.e. in Kg). The mix ratio

used to carry out the experiment is 1:2:4. Also, specifically, aluminium dross is

used to partially replace Ordinary Portland cement at 0%, 10%, 20%, 30%,

40%, 50% by weight and below details the calculation of the mixed proportion.

41

3.4.1 CALCULATION OF QUANTITY OF MATERIALS

Volume of mould, V = L x W x H - - - - - 3.1

Where; L = length of mould (m)

W = width of mould (m)

H = height of mould (m)

Mass of concrete, M = D x V - - - - - - 3.2

Where; D = density of concrete (kg/ m3)

V = volume of concrete (m3)

Mass per batch, Mb = M x n - - - - - - 3.3

Where; M = mass of concrete (kg)

n = no of cubes per batch

Applying % waste,

Total Mass of concrete per batch, TMb = % x (Mb) + Mb - - 3.4

Cement content = x TMb- - - - - 3.5

Fine aggregate = x TMb- - - - - 3.6

42

Coarse aggregate = x TMb- - - - - 3.7

Mass of water = (w/c) x cement content- - - - - 3.8

Where; (w/c) = water / cement ratio

3.5 SPECIMEN PREPERATION (PROCEDURE)

The batching of concrete wis done by weighing the different constituent

materials based on 1:2:4.

The Aluminium dross used is passing through 150µm sieve.

The materials is then mixed thoroughly before adding the prescribed quantity of

water and then mixed further to produce fresh concrete.

The freshly mixed concrete is then filled into a cone in three layers and rammed

as well and the slump obtained.

The fresh concrete is remixed properly and then filled into 9 moulds in

approximately 50mm layers with each layer given 25 strokes of the tamping rod

(each mix ratio gave nine (9) moulds of concretes per batch). The concretes is

towelled off level with the top of the moulds and the specimen stored under

damp sacking for 24hours in the laboratory before de-moulding and storing in

water for the required curing age.

43

The same exercise is also done for other concrete samples using different

replacement ratios of Ordinary Portland Cement to Aluminium Dross with the

two different mix ratios and 54 cubes of concrete is produced.

Two control concretes is also produced in the same procedures using only

Ordinary Portland cement and the same mix ratios.

A total of 54 cubes is produced.

Figure 3.4 Aggregate Mix

3.6 EXPERIMENT CARRIED OUT

1. Slump test (For concrete mix with different replacement ratios)

2. Compressive strength test (For all the concrete cubes casted).

3.6.1 SLUMP TEST

Workability of a concrete can be measured by the concrete slump test, a

simplistic measure of the plasticity of a fresh batch of concrete following the

44

BS EN 12350-2 test standards. A relatively wet concrete sample may slump as

much as eight inches.

APPARATUS

- Truncated steel cone of 300mm high, 200mm diameter at the base and

100mm diameter on the top

- 16mm diameter Compacting rod

- Trowel

- Scale for measurement

PROCEDURE

1. The mold for the slump test is a frustum of a cone, 300 mm (12 in) of

height. The base is 200 mm (8in) in diameter and it has a smaller opening

at the top of 100 mm (4 in).

2. The base is placed on a smooth surface and the container is filled with

concrete in three layers, whose workability is to be tested .

3. Each layer is temped 25 times with a standard 16 mm (5/8 in) diameter

steel rod, rounded at the end.

4. When the mold is completely filled with concrete, the top surface is

struck off (leveled with mould top opening) by means of screening and

rolling motion of the temping rod.

45

5. The mould must be firmly held against its base during the entire operation

so that it could not move due to the pouring of concrete and this can be

done by means of handles or foot - rests brazed to the mould.

6. Immediately after filling is completed and the concrete is leveled, the

cone is slowly and carefully lifted vertically, an unsupported concrete

will now slump.

7. The decrease in the height of the center of the slumped concrete is called

slump.

8. The slump is measured by placing the cone just besides the slump

concrete and the temping rod is placed over the cone so that it should also

come over the area of slumped concrete.

9. The decrease in height of concrete to that of mould is noted with scale.

Figure 3.5: Concrete Slump

3.6.2 COMPRESSIVE STRENGTH

46

The compressive strength test is the test most commonly performed on

hardened concrete. Compressive strength is one of the main structural design

requirements to ensure that the structure will be able to carry the intended load.

Compressive strength increases as the water-cementitious materials ratio

decrease.

The strength of the compressed concrete cube is test with destructive test which

is the cube compression test. This test is based on the specification in BS EN

12350-3 and BS EN 12350-4.

The compressive strength of the specimen is affected by the specimen size.

Increasing the specimen size will reduce the strength, because there is a greater

probability of weak elements where failure starts in large specimens than in

small specimens. The interface between the hardened cement paste and

aggregate particles is typically the weakest location within the concrete

material. When concrete is stressed beyond the elastic range, micro cracks

develop at the interface and continuously grow until failure. The compressive

strength of the specimen is determined by dividing the maximum load carried

by the specimen during the test by the average cross sectional area.

Compressive strength = - - - - 3.9

PROCEDURE

A total of 54 cubes is produced for 1:2:4 mix ratio.

47

The procedure taken is:

1) The sand is prepared which have been sieve in sieve size 5 mm.

2) The material is weighed based on the specific mix ratio 1:2:4.

3) The materials is mixed manually using the different replacement

ratio(0%,10%,20%,30%,40%,50%) of aluminium dross with cement.

4) The moulds is thoroughly cleaned and the inner of it were all oiled.

5) The mixture is filled up into the mould until it was totally filled, after that

tapping rod is used to compact it at least 25 strokes per layer.

6)The mixed ratio and the date of performing the experiment is written on the

sample, after which the sample is taken to the curing bath for curing.

7) At the day of determining the Compressive strength of the material, it is

taken out of the curing bay for crushing. It is endeavoured that all the cubes that

is crushed is placed at the centre of the compressive plate to ensure the load is

uniformly distributed at the cube surface.

8) The ultimate load or cube failure load is displayed on the compressive

machine screen. All the testing data is recorded.

3.7 CURING OF CONCRETE

Curing is a process taken to retain the moisture content of sample which could

help the hydration process of cement. According to D.E Shirley (2000), curing

is an important process as it will minimize drying and heat in concrete, besides

allowing the concrete to build it strength to resist stress. Curing of sample is

48

held along the age of concrete, until the sample is going to be tested. Curing can

be done by air dry, using wet gunny sack or submerge in water.

In this research work, the concretes produced is cured by Immersion method

whereby it lasted for 28 days, after which they were brought out from the curing

bay.

Figure 3.6: Curing bay

Figure 3.7: Concrete before Curing Figure 3.8 Concrete after Curing

49

CHAPTER FOUR

DATA ANALYSIS AND RESULT PRESENTATION

4.1 INTRODUCTION

Tests is carried out successfully, below are the result data.

4.2 CALCULATION OF QUANTITY OF MATERIALS USED

Volume of mould = 150mm x 150mm x 150mm

= 0.15m x 0.15m x 0.15m

= 3.375 X 10-3 m3

Unit weight of concrete = 2400kg/m3

Mass of concrete = Density x Volume

= 2400 X 3.375 X 10-3

= 8.1kg

TOTAL RATIO VALUE = 1+2+4 = 7

50

No of cubes per batch = 9 (i.e. 3 cubes each for 7, 14 and 28 days respectively

in order to get the average strength), therefore batch implies for control mix (0%

replacement) and test mix of 10%, 20%, 30%,40% and 50% replacement of

cement with aluminium dross. For these nine cubes

= 8.1 X 9 = 72.9kg

Add 5% waste = 72.9 X 5/100 = 3.65kg

= 72.9 + 3.65 = 76.55kg per batch

Mass of cement = = 10.94kg

Mass of fine = = 21.87kg

Mass of Coarse = = 43.74kg

The water / cement ratio adopted in this concrete mix is 0.5. To calculate the

mass of water used,

Mass of water = 0.5 x Mass of cement

= 0.5 x 10.94 = 5.47kg

TABLE 4.1 - QUANTITY OF MATERIALS USED

51

S/

N

% of

cement

(%)

% of

Dross

(%)

Cement

(Kg/m3)

Aluminium

Dross

(Kg)

Coarse

aggregate

(Kg)

Fine

aggregate

Water

(Kg)

1 100 0 10.94 0.00 43.74 21.87 5.47

2 90 10 9.85 1.09 43.74 21.87 5.47

3 80 20 8.75 2.19 43.74 21.87 5.47

4 70 30 7.66 3.28 43.74 21.87 5.47

5 60 40 6.56 4.38 43.74 21.87 5.47

6 50 50 5.47 5.47 43.74 21.87 5.47

4.2 SLUMP TEST VALUES

Table 4.2 Slump Values for Mix ratio of 1:2:4

S/N Date of Execution

Replacement ratio

%

Water / Cement

ratio

Height of cone(mm)

Final Height of Concrete

(mm)

Slump Value(mm)

1 22/07/15 0 0.5 300 270 302 22/07/15 10 0.5 300 285 15

3 22/07/15 20 0.5 300 290 10

4 24/07/15 30 0.5 300 297 35 24/07/15 40 0.5 300 299 16 24/07/15 50 0.5 300 300 0

4.3 COMPRESSIVE STREGHT TEST RESULTS

TABLE 4.3 – COMPRESSIVE STRENGTH RESULT FOR 7 DAYS

52

CUBE NO

DATE OF

CAST

DATE OF

TEST

WEIGHT

(Kg)

CRUSHING LOAD

(KN)

COMPRESSIVE STRENGHT

(N/mm2)

A7 - 1 22/07/15 29/07/15 9.00 510.98 22.70

A7 - 2 22/07/15 29/07/15 9.00 439.06 19.51

A7 - 3 22/07/15 29/07/15 9.00 326.89 14.53

B7 - 1 22/07/15 29/07/15 8.70 391.28 17.39

B7 - 2 22/07/15 29/07/15 9.00 522.25 23.21

B7 - 3 22/07/15 29/07/15 9.00 502.52 22.33

C7 - 1 22/07/15 29/07/15 8.90 477.94 21.24

C7 - 2 22/07/15 29/07/15 9.00 363.74 16.17

C7 - 3 22/07/15 29/07/15 8.90 491.23 21.83

D7 - 1 24/07/15 31/07/15 9.00 439.35 19.53

D7 - 2 24/07/15 31/07/15 8.80 290.09 12.89

D7 - 3 24/07/15 31/07/15 8.95 289.08 12.85

E7 - 1 24/07/15 31/07/15 8.50 316.08 14.05

E7 - 2 24/07/15 31/07/15 8.80 286.42 12.73

E7 - 3 24/07/15 31/07/15 8.50 213.51 9.49

F7 - 1 24/07/15 31/07/15 8.80 215.78 9.59

F7 - 2 24/07/15 31/07/15 8.40 208.96 9.29

F7 - 3 24/07/15 31/07/15 8.30 216.26 9.61

53

TABLE 4.4 - COMPRESSIVE STRENGTH RESULT FOR 14 DAYS

CUBE NO

DATE OF

CAST

DATE OF

TEST

WEIGHT

(Kg)

CRUSHING LOAD

(KN)

COMPRESSIVE STRENGHT

(N/mm2)

A14 - 1 22/07/15 07/08/15 8.80 655.83 29.15

A14 - 2 22/07/15 07/08/15 8.60 501.16 22.27

A14 - 3 22/07/15 07/08/15 8.30 597.67 26.56

B14 - 1 22/07/15 07/08/15 8.90 514.65 22.87

B14 - 2 22/07/15 07/08/15 8.80 374.07 16.63

B14 - 3 22/07/15 07/08/15 8.50 528.72 23.50

C14 - 1 22/07/15 07/08/15 8.60 509.71 22.65

C14 - 2 22/07/15 07/08/15 8.90 480.77 21.37

C14 - 3 22/07/15 07/08/15 8.70 501.88 22.31

D14 - 1 24/07/15 10/08/15 8.60 443.81 19.72

D14 - 2 24/07/15 10/08/15 8.60 256.41 11.40

D14 - 3 24/07/15 10/08/15 8.60 376.12 16.72

E14 - 1 24/07/15 10/08/15 8.20 232.65 10.34

E14 - 2 24/07/15 10/08/15 8.40 322.64 14.32

E14 - 3 24/07/15 10/08/15 8.40 280.33 12.46

54

F14 - 1 24/07/15 10/08/15 8.10 98.58 4.38

F14 - 2 24/07/15 10/08/15 8.20 96.09 4.27

F14 - 3 24/07/15 10/08/15 8.10 119.22 5.30

TABLE 4.5 - COMPRESSIVE STRENGTH RESULT FOR 28 DAYS

CUBE NO

DATE OF

CAST

DATE OF

TEST

WEIGHT

(Kg)

CRUSHING LOAD

(KN)

COMPRESSIVE STRENGHT

(N/mm2)

A28 - 1 22/07/15 20/08/15 8.80 700.00 31.11

A28 - 2 22/07/15 20/08/15 8.70 900.00 40.00

A28 - 3 22/07/15 20/08/15 8.40 860.00 38.22

B28 - 1 22/07/15 20/08/15 8.40 670.00 29.78

B28 - 2 22/07/15 20/08/15 8.80 820.00 36.78

B28 - 3 22/07/15 20/08/15 8.70 710.00 31.56

C28 - 1 22/07/15 20/08/15 8.60 720.00 32.00

C28 - 2 22/07/15 20/08/15 8.50 550.00 24.44

C28 - 3 22/07/15 20/08/15 8.40 640.00 28.44

D28 - 1 24/07/15 21/08/15 8.70 430.00 19.11

D28 - 2 24/07/15 21/08/15 8.50 455.00 20.22

D28 - 3 24/07/15 21/08/15 8.50 570.00 25.33

55

E28 - 1 24/07/15 21/08/15 8.10 430.00 19.11

E28 - 2 24/07/15 21/08/15 7.90 380.00 16.89

E28 - 3 24/07/15 21/08/15 8.60 440.00 19.56

F28 - 1 24/07/15 21/08/15 7.70 190.00 8.40

F28 - 2 24/07/15 21/08/15 8.20 280.00 12.44

F28 - 3 24/07/15 21/08/15 8.20 220.00 9.78

Note: the cube strength in N/mm2 is derived from dividing the force by 150mm

x 150mm.

4.4 AVERAGE COMPRESSIVE STRENGTH RESULT OF

CONCRETE(7DAYS AGE)

AVRG.A7 = = = 18.91

AVRG.B7 = = = 20.97

AVRG.C7 = = = 19.75

AVRG.D7 = = = 15.09

56

AVRG.E7 = = = 12.09

AVRG.F7 = = = 9.50

TABLE 4.6 – AVERAGE COMPRESSIVE STRENGTH AT 7 DAYS AGE

S/No

Replacement Ratio

(%)

Mix Ratio

AverageCompressive

strength

(N/mm2)

A7 0 1:2:4 18.91

B7 10 1:2:4 20.98

C7 20 1:2:4 19.75

D7 30 1:2:4 15.09

E7 40 1:2:4 12.09

F7 50 1:2:4 9.50

4.5 AVERAGE COMPRESSIVE STRENGTH RESULT OF

CONCRETE(14DAYS AGE)

AVRG.A14 = = = 25.99

AVRG.B14 = = = 21.00

57

AVRG.C14 = = = 22.11

AVRG.D14 = = = 15.96

AVRG.E14 = = = 12.37

AVRG.F14 = = = 4.65

TABLE 4.7 – AVERAGE COMPRESSIVE STRENGTH AT 14 DAYS

AGE

S/No

Replacement Ratio

(%)

Mix Ratio

AverageCompressive

strength

(N/mm2)

A14 0 1:2:4 25.99

B14 10 1:2:4 21.00

C14 20 1:2:4 22.11

D14 30 1:2:4 15.96

E14 40 1:2:4 12.37

F14 50 1:2:4 4.65

4.6 AVERAGE COMPRESSIVE STRENGTH RESULT OF

CONCRETE(7DAYS AGE)58

AVRG.A28 = = = 36.44

AVRG.B28 = = = 32.59

AVRG.C28 = = = 28.29

AVRG.D28 = = = 21.55

AVRG.E28 = = = 18.52

AVRG.F28 = = = 10.21

TABLE 4.8 – AVERAGE COMPRESSIVE STRENGTH AT 28 DAYS

S/No

Replacement Ratio

(%)

Mix Ratio

AverageCompressive

strength

(N/mm2)

A28 0 1:2:4 36.44

B28 10 1:2:4 32.59

C28 20 1:2:4 28.29

59

D28 30 1:2:4 21.55

E28 40 1:2:4 18.52

F28 50 1:2:4 10.21

TABLE 4.9– AVERAGE COMPRESSIVE STRENGTH FOR ALL THE

AGES

Cube

Replacement

Ratio

%

Average Compressive Strength

(N/mm2)

7 Days 14 Days 28 Days

A 0 18.91 25.99 36.44

B 10 20.98 21.00 32.59

C 20 19.75 22.11 28.29

D 30 15.09 15.96 21.55

E 40 12.09 12.37 18.32

F 50 9.50 4.65 10.21

4.5.0 GRAPHICAL REPRESENTATION OF DATA

60

Figure 4.1 - Bar chart of Slump value against % replacement ratio

Figure 4.2 - Bar chart of Average compressive strength against % replacement ratio at 7 days

61

Figure 4.3 - Bar chart of Average compressive strength against % replacement ratio at 14 days

Figure 4.4 - Bar chart of Average compressive strength against % replacement ratio at 28 days

62

Figure 4.5 - Graph of Slump Value against Replacement ratio

Figure 4.6 - Graph of Average compressive strength against Replacement ratio

at 7 days

63

Figure 4.7 - Graph of Average compressive strength against Replacement ratio

at 14 days

Figure 4.8 - Graph of Average compressive strength against Replacement ratio for 28 Days

64

Figure 4.9 - Graph of Average compressive strength against Replacement ratio for all samples

Figure 4.10 – Graph of average compressive strength against age for the various replacement ratios

4.8.0 DISCUSSION

4.8.1 COMPRESSIVE STRENGTH OF CONCRETE

65

The compressive strength obtained at age 7,14 and 28 days is shown in table

4.3,4.4 and 4.5 respectively.

The mean compressive strength of the concrete cube specimens at 7,14 and 28

days is presented in Table 4.6,4.7and 4.8, Figure 4.9.

From the examination of the mean compressive strength test results on mix ratio

1:2:4 by varying the percentage replacement ratio of cement with aluminium

dross (0%, 10%, 20%, 30%, 40%, 50%), the following observation are made

1. From Table 4.6 and Figure 4.2, the compressive strength at age 7 days

increases from 0% replacement to 10% replacement ratio followed by

decrease. the highest compressive strength is gained at 10% replacement

ratio

2. From Table 4.7and Figure 4.3, the compressive strength at age 28 days,

the highest value is at 0% replacement ratio with decrease in the 10%

replacement ratio

3. From Table 4.8 and Figure 4.4 the compressive strength at age 28 days,

the highest value is at 0% replacement ratio with considerable decrease as

the replacement ratio increases.

66

4.8.2 CONCRETE WORKABILITY

The workability for specified replacement levels of Portland cement by

aluminium dross, maintaining a constant water-cement ratio was measured by

slump test.

As evident from the results of Table 4.2 and Figure 4.1 , there is an appreciable

decrease in the workability of concrete with increasing percent replacement of

cement by aluminium dross.50% replacement ratio having a slump value of 0,

indicating that the concrete is not workable.

Therefore it is said that the aluminium dross absorbs water since the increase in

percentage ratio of aluminium dross, results decrease in slump value at a

constant water-cement ratio

67

CHAPTER FIVE

CONCLUSION AND RECOMMENDATION

5.1 CONCLUSION

The effects of partial replacement of aluminium dross with cement in concrete

production have been studied. As there was a appreciable decrease in the

workability of concrete with increasing percentage replacement of cement with

aluminium dross at constant water-cement ratio, it is said that aluminium dross

absorbs water more.

Significant increase is noted at 10% replacement ratio concrete of 7days age

compared to 0% replacement ratio( conventional concrete), at 14 and 28 days

0% replacement ratio supersedes other replacement ratio in strength, this

indicates that aluminium dross is no suitable for use of concrete where strength

is demanded. Aluminium dross can be used in production of blocks, building

sub-floor and panels.

Aluminium dross decreases the workability and strength of concrete.

5.2 RECOMMENDATION

This study concentrates on the compressive strength and workability. Further

work should be done on various mixes, also various tests should be done such

as flexural strength, tensile strength, shear strength, water absorption, resistance

to impact, creep, etc. The knowledge of the above properties will greatly assist

68

engineers, builders and designers when using the materials for construction

works.

Also the how aluminium dross affects concrete and how it combines with

cement chemically should be further researched.

69

REFERENCES

British Standards Institute, “Testing Concrete—Methods of Testing Hardened

Concrete for Other than Strength,” BS 1881-5:1970, London, 36 pp.

Brough M. (2007), “Aluminium lightens the environmental load”,

Vision the newsletter of the Foresight and Link Initiative,

No4,Winter2002.URL<http://www.berr.gov.uk/files/file30193.pdf >.

BS 881: 1992, “Specification for aggregates from natural Sources for

concrete”, London: British standard institution.

BS 1881: Part 116: 1983, “Method for determination of Compressive strength

of concrete cubes”, London: British Standard Institution.

Chan Dai (2012), “Development of aluminium dross-based material for

Engineering applications”, M.Sc. Thesis, Material Science and

Engineering, Worcester Polytechnic Institute.

Duarte Pereira A. et al (2000), “Mechanical behaviour of Portland cement

mortars with incorporation of Al-containing salt slags”, Cement and

Concrete Research, Vol. 30, pp. 1131-1138.

70

Dunster A.M. et al ( 2005), “Added value of using new industrial waste

Streams as secondary aggregates in both concrete and asphalt”,

DTI/WRAP Aggregates research Programme STBF 13/15C, The Waste

and Resources Action Programme.

Elinwa A.U. (2011), “The use of aluminium waste for concrete production”,

Journal of Asian Architecture and Building Engineering, Vol. 10, No 1,

pp. 217-220

Ewais E.M.M et al (2009), “Utilization of aluminium sludge and aluminium

slag (dross) for the manufacture of calcium aluminate cement”, Ceramics

International, Vol. 35, pp. 3381-3388.

Gwinner, D.S. (1996), “Environmental Issues in the Aluminium Reclamation

Industry”. In: II Seminário Internacional de Reciclagem de Alumı́Tnio,

São Paulo, SP, Brazil.

Hollins O. (2007), "Aluminium industry could dramatically reduce Land Filling

of furnace waste". URL<

http://www.ohlsti.co.uk/ohl/newsletter/ohl_wmr312.pdf >.

Kevorkijan V. M. (1999), “The Quality of Aluminium Dross Particles And

Cost-effective Reinforcement for Structural Aluminium-based

Composites”, Composites Science and Technology, Volume 59.

71

Kulik et al (1990), “Aluminium Dross Processing in The 90’s”, in 2nd Int.

Symp. Recycle. Met. Eng. Mater, TMS-AIME, Warren dale, PA, 1990,

pp.427

Neville A.M. (1994), “Properties of Concrete” Third Edition, Longman

Scientific and Technical, Longman group UK LTD.

Peterson et al (2002), “Review of Aluminium Dross Processing”, Light Metals,

TMS-AIME, Warren dale, PA.

Puertas F. et al (1999), “Behaviour of Cement mortars containing an industrial

waste from aluminium refining stability in Ca(OH)2 solutions”,Cement

and Concrete Research, V. 29, pp. 1673-1680.

Shinzato M.C. et al (2005), “Solid waste from aluminium Recycling process:

characterization and reuse of its economically valuable constituents”,

Waste Management, Vol. 25, pp. 37-46.

WIKIPEDIA (2013), "Compressive Strength”.

Zongjin Li (2001), “Advanced Concrete Technology” First Edition, John Wiley

and Son INC, Hoboken New Jersey.

72