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MEASUREMENT AND CONTROL OF MOISTURE
CONTENT OF AGGREGATES, WOOD AND BRICK USED
ON CONSTRUCTION SITE
BY
BORISANMI HENRY MONDAY
F/HD/07/3510077
DEPARTMENT OF BUILDING TECHNOLOGY
SCHOOL OF ENVIRONMENTAL STUDIES
YABA COLLEGE TECHNOLOGY
YABA LAGOS
NOVEMBER 2009
1
MEASUREMENT AND CONTROL OF MOISTURE CONTENT OF
AGGREGATES, WOOD AND BRICK USED ON CONSTRUCTION
SITE
BY
BORISANMI HENRY MONDAY
F/HD/07/3510077
PROJECT WORK SUBMITTED TO THE DEPARTMENT OF
BUILDING TECHNOLOGY IN SCHOOL OF ENVIRONMENTAL
STUDIES
YABA COLLEGE TECHNOLOGY.
IN PARTIAL FULFILMENT OF THE AWARD OF NATIONAL
DIPLOMA IN BUILDING TECHNOLOGY
NOVEMBER 2009
2
CERTIFICATION
This is to certify that the project: measurement and control of moisture
content of aggregate, wood and timber used on construction site.
Submitted to the Department of Building Technology for the Award of
Higher National Diploma (HND) Building Technology is a record of work
carried out by:
BORISANMI HENRY MONDAY
{F/HD/07/3510077}
Of
The Department of Building Technology
Yaba College of Technology
BORISANMI H. M. ………………… …………………..
Author’s name Signature Date
BLDR. C. T UDOH ………………... ………………….
Supervisor’s name Signature Date
BLDR. ATERE O. V. ………………… …………………….
Head of Department signature Date
3
DEDICATION
This project is dedicated to Almighty God the creator of heaven and earth
for His infinite mercy and protection throughout my study period.
And also to my beloved parent and family of: Ven. & Mrs. S.A Borisanmi
for their support, both financial and morally throughout the course of my
study.
4
ACKNOLEDGEMENT
I want to use this medium to acknowledge my able supervisor “Bldr C.T.
Udoh for his support and supervision towards the success of this project
work. Also appreciate the effect of Mr. Odunekan for his great effort during
my practical work, thanks a million.
My gratitude goes to my parent Ven & Mrs S.A. Borisanmi, my brothers and
sisters, “the husband, the wife” “Ven & Mrs. Agboola, Mr & Mrs
Famodimu, Mr & Mrs. Gbemiga Borisanmi Jnr., Sis. Yemi and Sis. Toyin.
You are the best family in the world thanks.
My regards also goes to my cousins Mr. Irewole Oni and Walex, we are just
like blood brothers, thanks for the support during my stay both at home and
school. May God bless you real good.
I say a powerful thank you to my Mentor Tosin Martins and wife for the
advice and support financially.
5
At this junction I acknowledge my indebtedness to all to my friends Richard,
Alli-Balogun, Kayode, Bimpe, Lanre Awoyemi, Dotun, Tope, Opeoluwa,
Yinka, Aleshinloye Abiodun, Dennis, Samuel, williems, Ydallar, Instinct
productions in general + others and to my entire course mate, you are all
wonderful.
Lastly I can not but thank the authority ‘Yaba College of Technology’ for
giving the opportunity to be one of their students. Thanks.
Great Yaba Tech.
6
PREFACE
This project, “Measurement and Control of Moisture Content of Aggregate,
Wood and Bricks used on construction site” is one of the criteria for the
award of Higher National Diploma (HND) in the school of Environmental
studies, Yaba College of Technology. Through this project the author is now
familiar how to determine moisture content of construction materials.
7
TABLE OF CONTENTS
Certification i
Dedication ii
Acknowledgement iii
Table of Contents iv
Abstract v
CHAPTER ONE: INTRODUCTION
1.0 Background of the Study 1
1.1 State of the Problem 3
1.2 Aims and Objectives 4
1.3 Significance of The Study 5
1.4 Research Question 5
1.5 Scopes and Limitation 6
CHAPTER TWO: LITERATURE REVIEW
2.1 Aggregates 7
2.1. Types of Aggregates 7
2.2 Production of Aggregates 8
2.3 Production of Fine and Coarse Aggregates 8
8
2.4 Shape and Surface Texture of Aggregate 10
2.5 Table 1: Classification of Aggregate Shape 10
2.6 Storage of Aggregate 11
2.7 Grading Of Aggregate 11
2.8 Sieve or Screen Analysis of Fine And
Coarse Aggregate 12
2.9 Sampling of Aggregates 12
3.0 Properties of Aggregate 13
3.1 Bond of Aggregate 13
3.2 Strength of Aggregate 14
3.3 Other Mechanical Properties of Aggregate 14
3.4 Required Characteristics of Good Aggregate 15
3.5 Used Of Aggregats 16
3.6 Importance Of Aggregates 16
3.7 Special Aggregates 17
3.8 Moisture Content 17
3.9 Effects of Moisture Content 19
4.0 How Moisture Penetrate Into the Aggregate 20
4.1 Sand 22
4.2 Bulking Of Sand 24
9
4.2 Bulking Of Coarse Aggregate 26
4.3 Fig IV: Range Of Moisture as They
Affect Aggregate State. 26
4.5 Absorption and Surface Moisture 26
4.6 Measurement of Moisture Content
4.7 Control of Aggregate from Mositure On Site 29
4.8 Wood 30
4.9 Wood Properties 31
5.0 Hardwoods 32
5.2 Types of wood 35
5.3 Moisture in wood 36
5.4 Influence of moisture content 38
5.5 Brick /Block 39
5.6 Manufacture of Bricks 40
5.7 Brick Laying 41
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CHAPTER THREE: RESEARCH METHODOLOGY
3.2 Population for The Sample 44
3.3 Samples 44
3.4 Sample Selected 45
3.5 Moisture Content Test 45
3.6 Used Apparatus 46
3.7 Drying Method 46
3.8 Method Data Analysis 47
CHAPTER FOUR: ANALYSIS OF DATA AND DISCUSSION OF
RESULTS
4.1 Moisture Content Test 48
4.3. Findings/Results 50
4.4 Discussion Of Results 50
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CHAPTER FIVE: CONCLUSION AND RECOMMENDATION
5.1 Conclusion 51
5.2. Recommendation 51
5.3 Suggestion For Further Studies 53
5.4 References 54
5.5 Appendix 56
12
ABSTRACT
This project is based on the measurement and control of moisture content of
Aggregate, Wood and Bricks used on construction site. Dry method was
used in this project work. Under the drying method, oven drying was used to
determine the moisture content of the aggregate.
The aggregates used for the test include fine aggregate (natural pit sand) and
coarse aggregate (natural pit gravel and crushed gravel).
Wood: Mariana (softwood), itara (hardwood), Arere (softwood),
Parana(softwood), Eku (hardwood), Balsa(Hardwood),
mahogany(hardwood). And also Brick/block.
Finally, it was found that the method used was relevant and effective for
determination of moisture content of construction materials.
13
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Building /shelter is one of the major needs of human beings, it is mostly
constructed by engineers, builders or contractors to meet a number of
different functional requirements. While it is exposed continuously to a wide
varieties of destructive agencies of forces.
The most vital aspect of the processing of construction is the decision
bothering on the choice of measurement and control of moisture content of
aggregate used on construction site that will be able to satisfy the basic
principle’s of modern construction works in order to achieve its purpose and
requirements.
Blackledge (1990) stated that: Aggregate are inert materials (i.e. chemically
uncreative component concrete however gives economical, durable
materials. Aggregate are classed as fine and coarse aggregates.
Generally, various sands are used as fine aggregates and coarse aggregate
are either water run gravel or crushed rocks quality of product.
14
Therefore, engineer must however be satisfied that the source selected will
consistently supply the quality of aggregates which he has approved.
To my site, a network of good construction is a necessity and not a luxury.
These aggregates are needed to improve good construction on our site,
before we can achieve this proper measurement and control of moisture
present in the aggregates must be taken into consideration. That is, the mass
of water in a simple of material such as sand and gravel contain should be
known before adding more at the mixer so that the total amount of water in a
mix can be controlled and consistency ensured.
Also, the engineer or builder in construction site is responsible for the
carrying out of this operation before the actual progress of work for
efficiently and effectiveness in order to boost good workmanship and
sensivity of the concrete/structural member of the work.
Orehard (1990) reported that the measurement of the moisture content of
aggregate is basically a very simple operation but it is complicated by
several factors. Aggregate will absorbed a quantity of water depending on its
type and thus, the water content can be quoted in terms of the weight of
aggregate, when absolute dry surface and when wet the water content can be
15
free water content or the total water content which include the absorbed
water plus the free water.
For site used, the method adopted must be accurate and must need only
simple apparatus that can easily be replaced if damaged.
Method of making the determination attainable include;
i. Drying method
ii. Displacement method gauging the size of sample by weight
iii Displacement method gauging the size of sample by volume.
By using any of the above methods, it will help the builder to achieve
quality aggregate free from moisture for construction works.
1.1 State of the Problem
The problem caused by moisture on aggregate attribute in construction work
includes;
I. Strength is normally considered to be the most important property
in relation to mature concrete. It is noted that during concreting, to
check moisture content of aggregate prior to batch so that accurate
adjustment of batch weights can be made necessary: batch
quantities of aggregate must be increased if free water, present and
the amount of free water in the aggregate should be deducted from
16
the water to be added. Excess water definitely wills reduces/affect
the strength produced by the aggregate.
II. Workability is defined as the property of concrete, which
determine of aggregate to be place compacted and finished. Major
factor affecting workability is water content (usually expressed as
volume in liters per cubic meter of concrete). For a given aggregate
size and type workability is highly sensitive to changes of water
content-for example, in the case of 20mm. irregular aggregate, a
water content of 160litres per cubic metre would result in high
workability, also affecting workability are maximum aggregate
size and shape. Its depend on the mix ratio which end up resulting
to affect the workability.
1.5 Aims and Objectives
The aim of this research is to measure moisture content of aggregates used
on the construction site. The objectives are;
i. To determine moisture content by using Drying method
ii. To know the moisture content by using displacement methods
ganging the size of sample by weight.
17
1.6 Significance of The Study
This research is to reveal to the various builder/student the required water
content of every mix in construction aggregate, whenever the aggregate is
moisturized, so as to achieve standard mix ratio.
Presence of large content of moisture in wood (timber) would inhabit growth
of algae, which causes decay of timber. In molded block/bricks would cause
the unhydrated cement to hydrate to a large extent. Therefore the control of
moisture content of timber to the minimum amount would enable such
timber to provide the service intended to serve over the considerable long
time without being affected by algae. Enhancing the moisture content of the
moulded bricks/blocks on the other hand would help material’s
producers/manufacturers to produce sound blocks/bricks.
1.7 Research Question
- What are the effects of the increase in water content on freshly
mixed concrete using aggregates of varying conditions?
- Are there any differences in the weight of aggregates when their
conditions are altered?
- Are there any allowances for moisture in the calculation of batch
quantities?
18
- As a result of present of moisture on wood, what is the likely
defect caused by moisture?
- Are there any form of deformation on brick/blocks as a result of
moisture/
- Are there any differences between natural and artificial aggregate,
in what area their function differ from the other.
- What is the best method of drying wood to a required level of
moisture content?
- Can aggregate make a considerable difference to the properties of
wet concrete.
1.5 Scopes and Limitation
This study is focused on the measurement and control of moisture
content of aggregate (used on concrete making), wood, blocks/bricks
used on construction sites. Study will be based on fine and coarse
aggregate.
19
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 AGGREGATES
Smith (1978) stated that, An aggregate is a material in granular or particle
form, such as sand or gravel, which is added to the class of materials known
as binders (e.g cements, hydraulic limes, plaster and bitumen) to produce a
solid mass on hardening, since most aggregates are inert and undergo no
chemical action with the binder, the strength of the combine mass depend
on;
a. The specific adhesion or sand which develops between aggregate and
binder.
b. The mechanical key or interlock which develops between the
constituent particles in virtue of their shape, size and surface texture.
2.1. TYPES OF AGGREGATES
Smith (1978) says that: there are two type of aggregate natural and artificial.
Natural aggregates mostly used has a relative density of about 2.6 although
both higher density and lower density material is used for special purposes;
nearly all the artificial aggregates have a low relative density.
20
NATURAL AGGREGATES
The natural aggregates available vary in different part of the country as
consequently do their properties. The main rock groups suitable for concrete
are basalt, flint gabbros, granite, gristone, limestone, porphyry and quartzite.
ARTIFICIAL AGGREGATES
Artificial aggregate include crushed brick, blast furnace slag and numerous
light weight and special aggregates.
2.2 PRODUCTION OF AGGREGATES
2.3 PRODUCTION OF FINE AND COARSE AGGREGATES
Sand and gravel are obtained either from pits or by dredging from the
bottom of rivers or from the sea bed. Pits are termed “wet” or “dry”
according to the water level in the vieinity, although some pits which would
otherwise be wet are dried out by pumping. The deposit are usually covered
with overburden which has to be removed by scrapers, mechanical shovel,
dragline or by always straight forward owing to the presence of faults and
dips in the gravel seams, and unless care is taken to remove these materials
occasional load of dirty aggregates occur.
21
The sand and gravel are then excavated by mechanical shovels in dry pits:
by dragline in both wet and dry pits, and by means of crane and grab, or
suction pumps, in wet pits. Gravel seams often orclic beds of clay, and it is
especially necessary that the inclusion of lumps of clay in the gravel should
be avoided since even with vigorous washing the clay lumps are extremely
difficult to remove. The danger of the inclusion of clay lumps is greater in
wet pit than in dry pit where dragline or grabs are used, because the driver is
unable to see the bottom, and therefore, to control the depth to which be
digs.
The mixed gravel and sand is usually conveyed from pit to the screening
plant by conveyor belt or in light trucks or by pipeline when the gravel is
raised by a suction pump, conveyor belt are commonly used to raise the
materials from ground level and sans is carried out either by means of
cylindrical rotating screen or by the more modern vibrating screens. A recent
improvement to vibrating screens has been made by carefully designing then
to produce a resonant effect. The sand and dirty water are usually carried
away together and are then dewatered by another mint. From the screening
unit, the sand and gravel are fed by gravity into suitable hoppers. Oversize
materials goes to a crusher and is often retain for rescreening.
22
The sand at some pits is treated further to modify its grading, by means of
classifier (Brooks, 1979)
2.4 SHAPE AND SURFACE TEXTURE OF AGGREGATE
Smith (1978) recorded that, aggregate shape can make a considerable
difference to the properties of the wet concrete. The shape may be classified
as rounded, irregular and angular.
Surface texture can be divided into six categories: glossy smooth, granular,
rough, crystalline and honey combed. It appears that the rougher the surface
texture the greater the bind the strength possible between the particles and
cement matrix. In a similar manner a larger adhesive strength should be
possible with the bigger area of angular aggregate than rounded material.
2.5 TABLE 1: CLASSIFICATION OF AGGREGATE SHAPE
SHAPE SOURCE APPEARANCE
Rounded River or Sea Little evidence of origin face
Irregular Laid dug Some wear, faces reduced in size
Angular Crushed rocks Little evidence of wear
23
2.6 STORAGE OF AGGREGATE
Unlike cement, aggregate are deliver to site and damped in the open, the
different size are being demarcated by partition or board.
It is sometimes not advisable to use a lay 30-40mm layer to avoid or to
protect it from intermingling and contamination by other materials.
Therefore, it is best to put down 100mm minimum thick layer of concrete
over the area where the aggregate will be stored, it is essential to provide
substantial partitions to separate the different aggregates size and to prevent
spillage from one bay to another. (Taylor, 1994)
2.7 GRADING OF AGGREGATE
Murdock et al (1979) stated that, aggregate varies in size from less than
0.1mm to 100mm. The largest size that can be used depends on the work to
be done.
The proportions of different size of aggregate will be in all mixes is known
as grading. To find the grading of an aggregate, a sieve analysis must be
carried out. The sieve sizes used for concrete aggregate are approximately
76mm, 38mm, 19mm, 9.5mm, 4.76mm, 2.38mm, 1.19mm, 595ụm, 297ụm,
145ụm, 74ụm. it is essential that amount used for sieving should be obtained
from rather larger sample taken from the stockpile to ensure that the material
tested is represented of the total.
24
2.8 SIEVE OR SCREEN ANALYSIS OF FINE AND COARSE
AGGREGATE
The purpose of this specification is to determine the particle size of fine and
coarse aggregate to be used in various test.
In this procedure, a weighted sample of dry aggregate is separated through a
series of screen of progressively smaller opening for determination of
particles size distribution.
In this specification, the results are dependent upon individual technique.
The test is placed in two categories mechanical sieving and hand sieving.
This excellent test determine the gradation of the aggregate which is so
important in mix design procedure. (Heins et al, 1981).
2.9 SAMPLING OF AGGREGATES
It is very important that nay sample of aggregate used for test purposes is
truly representative of the bulk from which it is taken. This can usually be
ensured by taking the sample in a number of increments from various
position and levels in a stockpile, or bin and mixing them together. If this
provides more materials than is needed, the sample may then be reduced by
quartering that is, dividing it into four similar parts, rejecting two, which are
25
diametrically opposite and remixing the remaining two. An alternative to
quartering is the use of a sample divider.
Draw
“DIAGRAM HERE”
3.0 PROPERTIES OF AGGREGATE
The properties of aggregates include;
i. Bond
ii. Strength
3.1 BOND OF AGGREGATE
Bond between aggregate and cement paste is an important factor in the
strength of concrete, especially the flexural strength, the full role of bond
being only now realized. Bond is due, in part, to the interlocking of the
aggregate and the paste coming to the toughness of the surface of the former,
a rougher surface, such as that of crushed particles, results in a better bond:
better bond is also usually obtained with softer, porous and mineralogical
heterogeneous particles.
26
3.2 STRENGTH OF AGGREGATE
Inadequate strength of aggregate represents a limiting case as the properties
of aggregate have some influence on the strength of concrete even when the
aggregate by itself is strong enough not to fracture prematurely. If we
compare concrete made with different aggregates we can observe that the
influence of aggregate in the strength of concrete is qualitatively the same
whatever the mix proportions and is the same regardless of whether the
concrete is tested in compression or in tension.
In general, the strength and elasticity o aggregate depends on its
composition, texture and structure.
3.3 OTHER MECHANICAL PROPERTIES OF AGGREGATE
Several mechanical properties of aggregate are of interest especially when
the aggregate is to be used on road construction or is to be subjected to high
wear. The first of there is toughness, which can be defined as the resistance
of aggregate to failure by impact. In addition to strength and toughness,
hardiness or resistance to wear is an important property of concrete used in
roads and in floor surfaces subjected to heavy traffic. (Neville, 1978).
27
3.4 REQUIRED CHARACTERISTICS OF GOOD AGGREGATE
i. All aggregate should be inert in water and should not contain
constituents that are liable to decompose or change in volume through
exposure to the atmosphere.
ii. Aggregate should be free from organic impurities which may affect
the setting and hardening properties of concrete.
iii. The particles should be free from coatings of dust or clay if the full
bond is to be developed.
iv. The compressive strength should be at least equal to that of developed
by the cement paste which binds the particles of the aggregate
together.
Most natural aggregate are in fact much stronger than the much
cement paste.
v. Aggregate with a low absorption value must be used for all concrete
that is exposed to the weather or is to be in contact with liquid.
This requirement is particularly necessary in concrete to be used for
liquid retaining or for reinforced concrete structures. A porous
aggregate is liable to cause the concrete to spall under the action of
28
frost. Special hard aggregate may have to be used in concrete exposed
to severe wear. (IIein et al, 1977).
3.5 USED OF AGGREGATS
i. Aggregates are used in making concrete
ii. Aggregates are used as hardcore in flooring
iii. Aggregates are used for rendering particularly when fine aggregate
are mixed with binder.
iv. Aggregates are used for block work, road work
3.6 IMPORTANCE OF AGGREGATES
Most concrete specification included a requirement for quality aggregates to
ensure the quality of the hardened concrete, although poor quality natural
sand may cause no deterioration under freeze/ than condition in air-entrained
concrete. It causes significant variation in mortar shrinkage and water
demand. Fine aggregate is used in concrete to improve the properties of the
particle mix, facilitate finishing, promote uniformity and inhibit segregation,
these improvement are accomplished largely by the grading size, shape and
surface texture of the particle.
29
3.7 SPECIAL AGGREGATES
i. Low-density concrete; to decrease foundation loads, increase thermal
insulation and reduce thermal inertia (light weight aggregate)
ii. High density concrete: for example, as required for radiation shielding
(baryles (bain sulphate) or iron- based aggregate.
iii. Abrasion- resistant concrete for floor (granite or carbon random
aggregate)
vi. Decorative aggregate; for example, crushed granite is available in
several different colour which can be revealed by use of an exposed
aggregate finish (Taylor, 1974)
3.8 MOISTURE CONTENT
Since absorption represents the water contained in the aggregate in a
saturated surface –dry condition, we can define the moisture content as the
water in excess of the saturated and surface dry condition. Thus, the total
water content of a moist aggregate is equal to the sum of absorption and
moisture contents.
Aggregate exposed to rain collects a considerable amount of moisture on the
surface of the particle, and except at the surface of stockpiles, keeps this
moisture over long periods. This is particularly true of fine aggregate and the
30
moisture content must be allowed for in the calculation of batch quantities
and of the total water requirement of the mix. In effect, the mass of water
added to the mix has to be decreased and the mass of aggregate must be
increased by an amount equal to the mass of moisture content. Since the
moisture content changes with weather and varies also from one stockpiles
to another, the moisture content must be determined frequently (Brooks
1994) Also, the moisture condition of an aggregates is also important
because this will affect the water content of the mix. This, in turn, affects the
cement paste that binds the mass to produce strength. The amounts of water
added to the concrete mixture should be adjusted for the moisture conditions
of the aggregates in order to maintain the design water content. A large
percentage of wet aggregate weight is actually water that will be added to
the mix. Even aggregate that appears dry can add a significant amount of
water to the mix. Since the water content is an extremely important indicator
of concrete quality, determine the moisture content of the aggregate used
and adjust the batch and water weight accordingly.
(hhtp://www.present.Org/pages/inc)
31
3.9 EFFECTS OF MOISTURE CONTENT
Effects of moisture /water content in aggregate of concrete include;
i. WORKABILITY
Workability can be best defined as the amount of useful initial work
necessary to produce full compaction. Presence of voids in concrete greatly
reduces its strength 5% of voids can lower strength by as much as 30% and
even 20% void can result in a drop of strength of more than 10 percent.
Therefore, the main factor affecting workability of water cement of the mix,
expressed in kilogram of water per cubic metre of concrete it ought to be
cohesive (Neville, 1981)
ii. STREGNTH
Strength of an aggregate product depends on the quality of the aggregates
used. Also the amount of water presence in it and during mix. If not property
measured can lower it strength.
iii. BLEEDING
Bleeding is known as water grain is a form of segregation in which some of
the water in the mix tends to rise to the surface of freshly placed concrete.
This is caused by inability of the solid constituents of the mix to hold all the
mixing water when they settle downwards due to water content.
32
It can be expressed as quantitatively as the total settlement per unit height of
concrete (Neville, 1981)
vi. ECONOMY
Economy refers to cost and is a direct function of proportioning. You can
easily make concrete with varying amount of ingredient (cement, water,
aggregate e.t.c) but each mix design will also vary in cost.
Obviously, it’s ideal to make the most use of the cheapest ingredients and
optimize the use of the most expensive.
The water content in aggregate will require more cement, in order to make it
workable. Therefore increase the cost.
4.0 HOW MOISTURE PENETRATE INTO THE AGGREGATE
Wilson (1984) recorded that, moisture is everywhere, present as an invisible
gas and this is not quite as easily controlled. There is water vapour in the air
all around us. It seeps into the cavities of construction assemblies in stud and
joist cavities, into the cores of mansory units.
Absorbed water is present in most construction assemblies and determines
their dimensional characteristics vapor moisture is not damaging, however it
is a fickle gas changeable, and becomes dangerous as it condenses liquefies,
33
and freezes, condensation hidden over a period of time in building assembles
can cause spalling of aggregates (concrete) and mansory.
Also, rain contribute greatly to these moisture content which can be as high
as 12-15%.
FIG 11. DIAGRAM REPRESENTATION OF MOISTURE IN
AGGREGATE
34
4.1 SAND
Taylor (1990) Stated that: sand is a fine aggregate formed by the natural
disintegration of rock, or it is artificially created by crushing stone or gravel
to the required sizes. Only small amounts of crushed stone sand are used in
plastering industry, its use being confined to special cement work on the
whole.
Natural sand has been formed over the centuries by the action of wind, rain,
forest and running water to break down rocks into small particles. These
small grains, varying in size, have been washed by the action of the seas and
rivers and deposited in certain areas which have in turn been moved inland
due to past changes of the earth’s formation. This is the reason for large
pockets or deposits of sand many miles inland.
The two main types of sand available at present are pit sand from inland
quarries and river sand obtained by dredging. Sea sand is unsuitable because
of the risk of effloresces due to the presence of salt. Crushed stone of ten
contain too much fines.
A good sand should contain a suitable proportion of large, medium and
small grains. The reason for this can be seen below.
35
FIG 111: SKETCH OF A SAMPLE OF SAND
36
If the sand is composed of large particles only, then there will be many
spaces or voids between the grains. This type of sand would require a lot of
cement to make a strong, dense mix. As a result the mix would be expensive
because of extra shrinkage would not be strong enough.
A well graded sand has medium sized grain to fill in the layer avoids and
small sized grains to fill in the smaller voids.
The functions of sand are:
1. To induce mix to shrink uniformly during the process of setting and
hardening irregular shrinkage being a general cause of cracking.
2. To lower the cost of the mixed material providing the biggest bulk of
the mix.
3. To assist workability, particularly on thicker application such as
floating coats.
4.2 BULKING OF SAND
In the case of sand, there is another effect of the presence of moisture, viz
bulking, which is an increase in the volume of a given mass of sand caused
by the films of water pushing the sand particles apart. While bulking per
does not affect the proportioning of materials by mass in case of volume
batching bulking result in a smaller mass of sand occupying the fixed
37
volume of the meaning box. Volume batching represents bad practice, and
no more than the proceeding warning in needed.
Water present in sand can affect mix proportion in a second way. Damps
sand takes up a layer volume than does dry or completely saturated sand.
Moisture contents of about 6 percent can ensure an increase in volume,
known as bulking of up to 30 percent. This means that if sand is batched by
volume there can be considerable variation in weight. A simple method in
used to find the percentage bulking which utilize the facts that dry sand
saturated and here the same volume. Damp sand is packed n a large
measuring cylinder and its volume found. This is then emptied out so that
some water may be added then replace gradually to saturate it.
The new sand volume is found.
Percentage bulking = Vw – Vs x 100
Vs
Where Vw = volume of moist sand
Vs = volume of saturated sand
(Neville, 1981)
38
4.2 BULKING OF COARSE AGGREGATE
Coarse aggregate shows only a negligible increase volume due to the
presence of free water, as the thickness of moisture film is vary small
compared with the particle size.
4.3 FIG IV: RANGE OF MOISTURE AS THEY AFFECT
AGGREGATE STATE.
4.5 ABSORPTION AND SURFACE MOISUTE
The following terms below should be clearly understood
i. Air dry: Dry at the surface though containing some interior moisture,
but less than the amount required to saturate the particles. In this
condition an aggregate can absorb more water into itself, and may still
39
appear dry on the surface. But absorbed moisture plays no part in the
lubrication of mixed concrete.
ii. OVEN DRY: Completely dry for practical purposes
iii. WET: The aggregates is itself saturated and carries an excess of
moisture forming film on the surface of the particles. The absorption
of different particles size of the not necessarily be taken as
representatives of the aggregate through the whole range of grading.
Since movement of moisture in the aggregate due to raining or change in
temperature which changes the length of aggregate at different stock piles or
locations (Brook, 1979)
4.6 MEASUREMENT OF MOISTURE CONTENT
The moisture content of aggregate is of vital importance on the control of
concrete worktability, strength and quality.
The measurement of the moisture content of aggregate is basically a very
simple operation but it is complicated by several factors. The aggregates will
absorb a quantity of water depending on its type and then the water content
can be quoted in terms of the weighted of aggregates when absolutely dry,
surface dry and when wet. The water content can be free water content, or
that held on the surface of the aggregates, or the total water content which
includes the absorbed water plus the free water. The specific gravity and
40
absorption of an aggregate depends also to some extent on its particle size
and this fact should be borne in mind when planning tests.
For fields use the method adopted must be quick, reasonably accurate, and
must need only simple apparatus which can easily be replaced damaged.
There are large numbers of different method of making the determination of
which are include.
i. Drying method
The aggregates before and after drying. Drying can be effected;
a. In an oven at a temperature of between 1000 and 1100c
b. In an open pan over a heater
c. By pouring over the aggregate an inflammable liquid which is
miscible with water and igniting it, methylated spirits and acetone are
suitable for this purpose.
41
4.7 CONTROL OF AGGREGATE FROM MOSITURE ON SITE
Aggregate should be stores, so that they are kept as uniform as
possible in grading and moisture content, also protect it from
interminingling and contamination by other materials.
Therefore, its is best to put down a 100mm minimum thick layer of
concrete over the areas where the aggregate will be store; concrete should be
laid to fall away from the mixer to facilitate free drainage of water from the
aggregate. And should extend well out from the mixer set-up so that all
deliveries can be tipped onto it.
- It is essential to provide substantial partitions to separate the different
aggregate sizes and to prevent spillage from one sand to another.
- Variation effects, which commonly occur in moisture content of fine
aggregate, will need adjustment to the water/cement ratio control.
- Variation in the moisture content of coarse aggregate as delivered, or
in the stockpiles, are usually not sufficient to have much effect on the
control of water/cement ratio.
- When fine aggregate is very wet, so sometime happen with fresh
deliveries, or after it has been raining, the moisture content can be as
high 12-15%. Therefore, adjustments are made to the water added at
42
the mixer excessive variation in workability and strength and
durability will result (Black ledge, 1990)
4.8 WOOD
Wood has been an important construction material since humans began
building shelters, houses e.t.c A very high proportion of house in the united
kingdom are of partly timber frame construction.
The word timber describes wood that has been cut for use in building.
Timber has many advantages as a building material. It is a light weight
material that is easy to cut, shape and join by relatively cheap and simple
hand or power operated tools in protection of walls, floors, and joinery
generally. As a structural material it has favourable weight to modulus of
elasticity ratios and coefficients of thermal expansion, k valves, density and
specific heat, with adequate sensible selection, fabrication and fixing and
adequate protection it is a reasonable durably material in relation to the life
of most building. Softwoods and hardwood are term used to classify
different timber.
The very majority of our homes have the roof construction of wood the
floors both at the ground and above are constructed of woods the floor both
43
at the ground and above are constructed of woods together with doors,
window, frames and skirting boards.
As time goes by wood became more costly; the higher standard of living
demanded by people throughout the world means that the cost of extracting
the logs from the forest, their transport, conversion to timber and fabrication
into desired shapes and distribution to the customers is progressively more
costly. In addition to this, the more accessible forest have long since been
cut, so that sizable timber must be sought for in remote areas. Replanting
programmes have not always been undertaken. This makes conservation of
existing timber in our building of prime important. Engineered wood product
are becoming a bigger part of the construction industry. They may be used in
both residential and commercial building as such structural and aesthetic
materials.
4.9 WOOD PROPERTIES
some types of wood are very hard and durable and some are flexible enouh
to bebent. “hardwood” is the one of the common types of woods. This is
obtained from trees that lose their leaves in winter. The other type of wood,
the “softwood” is aobtained frin evergreen trees like fir,pine and redwood.
All the woods fall between a range from very soft to very hard.
44
All type wood have distinctive grain structure. Wodds like white abd red
oak, ash and walnut havbeopen-pores in the form of small hole on their
surface that give a distinct textural quality to furniture piece like wooden
cupboard or wooden desks. When thw surface of this wood is stained, the
colour tends to collect in the “open-pores” abd apper darker than the rest of
the piece. There are other woods. These woods are have the smooth texture
and can take finish evenly. Apart from grains, one more characteristic of
many woods is unique figure on their surface such as quilting, birdseye,
fiddleback and spalting. These naturally occurring characteristics can make a
furniture acquire extraordinary beauty.
5.0 Hardwoods
Mahogany: is finely grained wood with reddish brown colour. It is highly
durable and can resist swelling, shrinkage and warping. It is extensively used
for quality furniture such as wooden cabinets, boat construction, wood
facings and veneers.
Walnut: has fine texture and is strong, easy to work with. It resists
shrinkage and warping and can take all types of finishes very well. It is
mostly used for making gunstocks, solid and veneered furniture, novelties,
cabinetry and wall paneling.
45
Oak: has good bending quality apart from being durable. It finishes well and
resists moisture absorption. Oak is good for furniture, trimming, boat
framing, wooden desks and flooring.
Maple: is a fine textured wood with immense strength and hardness. With
moderate shrinkage, maple machines well and is best in flooring, fine
furniture and woodenware such as bowling alleys.
Cherry: is close-grained wood and as resists warping and shrinking. It gets
red when exposed to sunlight. It ages well and is extensively used in cabinet
making, boat trim, novelties and solid furniture handles.
Rosewood: is close grained hard wood with dark reddish brown
Color. It has an exclusive fragrance. It is hard to work upon and takes high
polish. It is good for making musical instruments, piano cases, tool handles,
art projects, veneers and furniture.
Teak: is a hard and moisture-resistant wood. It resists warping, cracking and
decay and is best used in fine furniture, paneling, shipbuilding, doors,
window framing, and as a general construction wood.
Shesham: is also known as Indian rosewood and is rich medium brown
wood with deep grains. It is a fast-growing hardwoods and the functional
furniture made from it can deal with everyday stresses and strains without
46
loosing its attractive appearance. It is highly durable, easily carved and is
exclusively used for making furniture, particularly almirahs and cabinets.
5.1 Softwoods
Pine: has a uniform texture and is very easy to work with. It finishes well
and resists shrinkage, swelling and warping. It is widely used in house
construction, paneling, furniture, molding and for making wooden boxes.
Hemlock: is lightweight and machines well. It is uniform textured and has
low resistance to decay. It is mainly used for construction,
Lumber, planks, doors, boards, paneling, sub flooring and crates.
Fir: is uniformly textured and has low resistance to decay. It is non-
resinous, works easy and finishes well. Fir is used for making furniture,
doors, frames, windows, plywood, veneer, general millwork and interior
trim.
Redwood: is light, durable and easy to work with. It has natural resistance to
decay and is good for making outdoor furniture, fencing, house siding,
interior finishing, veneering and paneling.
Spruce: is a strong wood that finishes well and has low resistance to decay.
It possesses moderate shrinkage and light. It is good option for making
47
masts and spars for ships, aircraft, crates, boxes, general millwork and
ladders.
Cedar: is a reddish wood with sweet odor. It is very easy to work with,
uniform in texture and is resistant to decay. Cedar is extensively used in
chest making, closet lining, shingles, posts dock planks, novelties and
venation blinds.
The structure and composition of wood
The virtues of wood – it high strength to weight ratio ease of working with
tools and machines, its insulating and sound absorbing properties, resistance
to chemical and its inherent beauty, all reflect its structure and chemical
composition. Yet one
of the main disadvantages of wood its susceptibility to decay, is also a
feature of that same structure and composition
5.2 Types of wood
The timber are divided into groups
- hardwoods are timber converted from trees bearing flowers
(angiosperm) whereas
- Softwood are timber converted from the Gymnosperm, almost all
belong to the conifer.
48
Most of the species in the second group bear cones and needle-shaped
leaves. It will be seen therefore, that hardwood and softwood are technical
terms having an exact meaning although the hardwood are usually hard and
the softwood are soft, this is not invariable the case. Some species of
hardwoods are relatively soft (e.g. Balsa)
In building, softwood is by far the most important type of timber used for
construction and crevassing purposes, on a gross tonnage basis. Hardwood
have traditional been used for joinery and floors which are to undergo heavy
wear and their decoration properties have also influence their use in these
situations.
5.3 Moisture in wood
The moisture content of wood i.e. the amount it contains substantially
influences it physical and mechanical properties and in many cases
determine its suitability for one purpose or another. Water contained in
wood partially fills internal voids, i.e. the vessel canal the cavities in the
cells and the intercellular spaces, anal is known as the free moisture, and
partly saturates the cell walls and called the hygroscopic (to absorb moisture
from the air) or bound moistures. The bound moisture occupies the
intercellular space and is partly in colloidal linkage with a substance of
49
wood. The free and the hygroscopic can be removed from the wood by
drying. The chemical bound moisture, entering into the composition of the
matter forming the wood, can only be removed by chemical reaction. The
maximum amount of hygroscopic moisture to about 30% at a temperature of
20*: at this moisture content, known as the cell wall saturation point or fibre
saturation point, the moisture completely saturate the cell walls and any
future increase in moisture content can only take place through the free
moisture. i.e. by filling the voids in the wood. The fibre saturation point is
the limit of hygroscopic, as it corresponds to the maximum amount of
moisture Which can be taken up by wood which can be taken up by wood
when keep in air saturated with water vapour. As moisture contents is varied
from zero to the fibre saturation point both the volume and the linear
dimension of wood change. The increase in moisture content within the
indicated limit is accompanies by the phenomena swelling and a reduction
by shrinkage.
The reason for the contraction of wood when it is dried is the removal of
water from the intestacies between the chain molecule of cellulose and
hemicelluloses when consequently approach one another. The opposite
effect is called swelling contraction during the dry and swelling, during
damping the fibres always takes in a transverse direction and not observed
50
for the length. The den the wood i.e the higher its bulk density, the more
shrinkage and swells.
When moisture content is increased beyond the fibre saturation point, and
the water begins to occupy the voids of the cells, there is no further swelling.
Freshly cut timber contain 80-100% of moisture, while in softwoods the
moisture content of sapwood is 2-3times greater than that of the heartwood.
The moisture content of floated or refted timber can be high as 200%.
5.4 Influence of moisture content
It is necessary to specify that there shall be a certain amount of water, and no
more or less, in timber suitable for building.
Moisture content is stated as a percentage of the dry weight of the timber.
The dry weight of any piece of timber is its weight after it has been so dried
that further drying causes it to lose no more weight. This dry weight is
reasonably constant for a given cubic measure of each type of wood and is
used as constant against which the moisture content can be assessed. The
moisture content of timber should be such that timber will not appreciably
gain or lose moisture in the position in which it is fixed in a building.
Control of moisture in wood
51
Natural drying seasoning: This is when logs have been cut into timbers
they are stacked either in the open or in a rough open sided shed. The
timbers are stack with battens between them to allow air to circulate around
them. Timbers are left for several year until most of the moisture in the
wood has evaporated.
Artificial or kiln seasoning: As a result of great length of time required for
natural drying method and because sufficient low moisture content of wood
cannot be achieved, artificial method is largely used. This when the wood
has been converted to timber and they are placed in the enclosed kiln. Air is
blown through the kiln, the temperature and humidity is being regulated to
effect to drying more rapidly, but not so rapid as to cause damage to the
timber.
Moisture in wood can be best control by storing them in a shed, this will
reduce the their level of exposure to rainfall, dew e.t.c.
It can be sun dried naturally or with the use of natural air or use of industrial
fan.
5.5 Brick /Block
Bricks are blocks of clay that have been hardened through being fired in a
kiln or dried in the sun. over time, kiln-fired bricks have grown more
popular than sum-dried bricks, although both are still found worldwide.
52
Bricks have been in continual use for around 5000years, and brickwork from
this time still stands in the Middle East, a testament to its durability.
The Roman Legions first brought bricks to Britain, using mobile kilns to
construct roads, aqueducts and buildings across the country. Bricks were
especially favoured in the 18th and 19th Centuries, although their use has
declined over the last 50 years due to the increased availability of cement
and concrete.
5.6 Manufacture of Bricks
In the past, bricks came in many different shapes and sizes, but today’s
modern bricks tend to be a standard size of around 8” x 4’’ x 2’’. They
demonstrate a wide variety of textures, colours and finishes from yellows,
reds and purples, to smooth, rough and rustic. These are due to the mineral
variations found in the clay, and the method of manufacturing.
Bricks are traditionally manufactured by mixing clay with enough water to
form a mud that is then poured into a mould of the desired shape and size,
and hardened through fire or sun. Adobe bricks, very fashionable in parts of
the USA, are still made in this way with a mixture of clay and sand (and
sometimes manure and straw) being poured into a form, and then removed
and dried in stacks outside in the sun.
53
Compressed Earth Blocks (CEBs) were developed in the 1950s and are
similar to adobe bricks, except they are more compact and uniform. They are
manufactured from soil that is more sand than clay, and compressed using a
manual or motorized machine to produce a variety of block shapes,
including hollow designs for insulation. CEBs are highly energy efficient
using up to 15 times less energy than a fired brick. They are durable,
ecological, inexpensive, and utilize low technology. For this reason they are
increasingly used in developing countries as a sustainable building
technology.
Modern methods of brick manufacture are highly mechanized and automated
procedures whereby clay is extruded in a continuous column, wire cut into
bricks, and hydraulically pressed to ensure resistance to weathering. The
bricks are then dried and slow fired at around 1000-1200oC. In more recent
times, recycled glass and other waste materials have been introduced into
this process.
These materials have been found to reduce firing times, temperatures and
toxic emissions, improve brick strength and durability, and reduce waste
going to landfill.
54
5.7 Brick Laying
Bricks are laid flat in rows called courses, exposing either their sides
(stretcher) or ends (header). The pattern of overlap created by the course is
called a bond. There are several different kinds of bonds, including stretcher
(most common), Herringbone, English, Basket and Flemish. With all bonds,
the vertical joints between each course of bricks must not line up or the
structure will be warkened.
Bricks are usually held together by mortar, though some bricks such as
CEBs can be dry stacked. Mortar consists of sand, a binding agent
(traditionally lime but these days more often cement) and water, which is
then mixed to a thick paste. It is applied to a brick, which is then placed onto
another brick and allowed to dry.
Pointing refers to the visible edge of the mortar between the bricks, which is
finished with a special trowel to provide a decorative look to the brickwork.
When building a structure, a bed of mortar is laid on top of the foundation,
and the structure’s ends are built up first. A string is then stretched between
these ends to ensure each row of bricks stays level. Two layers of brick are
used to create a stronger structure, with a gap left in between for insulation
55
purposes. A wide range of structures including arches can be built using
bricks.
Bricks as a Sustainable Building Material.
Bricks are a versatile and durable building and construction material, with
good load-bearing properties, high thermal mass and potential low energy
impact. In the case of simple earth bricks such as adobe and CEBs, they
measure high on the sustainability index, being made from locally available
(and abundant) materials, of clay, sand, and water, using low technology
compression equipment, solar energy or kilns. While modern methods of
bricks construction have a much lower sustainability index, the UK brick
industry has developed a strategy to minimize its environmental impact and
increase its energy efficiency and use of renewable energies.
Overall, bricks are a good example of a sustainable building practice and are
currently gaining in popularly around the world.
Moisture absorption
The amount of water a brick will absorb is a guide to its density and
therefore its strength in resisting crushing. The level of water absorption is
most critical for brick to be used. Absorption rates vary between 1% and
35%.
56
CHAPTER THREE
3.0 RESEARCH METHODOLOGY
3.1 This chapter of the project involves the processes engaged in carrying
out the practical/experiment and collection of result to provide solution to
research question.
3.2 POPULATION FOR THE SAMPLE
The population of the practical for this research concentrate on moisture
determination on construction material. These materials; fine aggregate
coarse aggregate, various types of wood and brick were used, for the project
for the purpose of construction work.
3.3 SAMPLES
The samples for this project were measured weight as stated.
20kg of fine aggregate and.
32kg of 10mm coarse aggregate taken to the laboratory wood.
200mm x 600mm Mariana (softwood)
200mm x 600mm Itara (hardwood)
200mm x 600mm Arere (softwood)
200mm x 600mm Parana (softwood)
57
200mm x 600mm Eku (Hard wood)
200mm x 600mm Balsa (Hard wood)
3.4 SAMPLE SELECTED
Sample selected for this test were obtained from more than one location. The
aggregate samples used are natural pit gravel, natural coarse aggregate and
crushed granite. Each sample were mixed together to distribute evenly for
the test.
Also test were conducted on different types of wood (Hard and soft wood).
The types of wood tested includes: Mariana (softwood), itara (hardwood),
Arere (softwood), Parana(softwood), Eku (hardwood), Balsa(Hardwood),
mahogany(hardwood). And also Brick/block.
3.5 MOISTURE CONTENT TEST
Drying method was used to determine the moisture content of all the
samples listed above, that is, the mass the ratio of the weight of water to the
weight of dry sample of the materials to be tested.
Moisture content (M.C) = Weight of water x 100.
Weight of sample
58
3.6 USED APPARATUS
Digital balance
Drying can
Scoop
Drying oven
3.7 DRYING METHOD
This method was adopted through out this project to determine the content
of the listed samples.
FOR AGGREGATE
The specimen for the test was kept in polythene bag to avoid equilibrium
moisture content in the laboratory. And the sample was weight after mixing
the material to distribute the moisture evenly. The sample was oven dried for
59
2hours (start time: 3:55 p.m, stop time 5:55 p.m) with constant temperature
of 105*C, after which the weight of the dried sample was obtained. The
method of calculation used is thus:
Moisture loss= (container + wet sample) - (container + dry sample)
Dry sample= (container + dry sample) – (container empty)
Wood test was performed. Thee initial weight of the woods were measured
and recorded, after it was oven dried and also measured to determine the
moisture content.
The method of calculation used is thus:
Moisture content = Weight when cut – Oven dry weight x 100
Oven dry weight
The same was done on brick.
3.8 METHOD DATA ANALYSIS
The data collected from laboratory practical work will be represented in
tabular form.
60
CHAPTER FOUR
4.0 ANALYSIS OF DATA AND DISCUSSION OF RESULTS
4.1 MOISTURE CONTENT TEST
The result of moisture content using drying method only.
4.2 DRYING METHOD
The result of the moisture content for all the samples used are shown in the
table below.
TABLE 1: AGGREGATE MOISTURE CONTENT DETERMINATION
MOISTURE CONTENT IN AGGREGATE
DETERMINATION
SIMPLE
FINE
AGGREGATE
NATURAL
GRANITE
CRUSHED
GRANITE
Container + wet sand 56.1 55.0g 50g
Container + dry sand 52.1 50.0 45.0
Empty container 16.1 5.0 5.0
Dry sand 36.0 45g 40g
Moisture loss 4.0 5.0 5.0
Moisture content 11.1% 11.1% 12.5%
61
TABLE 2: MOISTURE CONTENT IN WOOD (TIMBER)
WOOD TYPES MOISTURE
INITIAL
WEIGHT
DRY
WEIGHT
MOISTURE
LOSS
MOISTURE
CONTENT
Maniana soft
wood
40g 35.0 5.0 14.3%
Itara-hard wood 30.0 28.0 2.0 6.7%
Arere soft wood 20.0 18.0 2.0 10.0%
Paranan wood 20.0 16.0 4.0 20%
Eku Hard wood 40.0 35.0 5.0 12.0%
Balsa(Hardwood), 45.0 40.0 5.0 11.1%
Mahogamy hard
wood
35.0 30.0 5.0 14.3%
TABLE 3: MOISTURE CONTENT IN BRICK
DETERMINATION SIMPLE READINGS
Brick + moisture (initial weight) 365g
Dry brick 355
Moisture loss 10.0
Moisture content 2.8%
62
4.3. FINDINGS/RESULTS
From table 1, the result shows that the moisture content of natural pit sand,
natural granite to be 11.1%, 11.1% and 12.5 respectively.
From table 2, mariana (softwood), Itara (hardwood), Arere (softwood),
parana (softwood), eku (hardwood), Balsa (hardwood), mahogany
(hardwood) to be 14.3%, 6.7%, 10.0%, 20.0%, 12.0%, 11.1% and 14.3%.
From table 3, Brick shows moisture content of 2.8%
4.4 DISCUSSION OF RESULTS
From the result or data obtained it can be deducted from the tables
The method of drying which must have ensured an accurate dry
weight
The quantity of aggregate used which was 0.5kg since adequate
balance was used for the weighting of the sample tested.
It was discovered from table 1 that granite has different moisture
content, for instance natural pit granite and crushed granite.
It was of observed that moisture content varies in wood in respective
to the type of the wood.
63
CHAPTER FIVE
5.0 CONCLUSION AND RECOMMENDATION
5.1 CONCLUSION
To conclude this research work various methods was carried out for
determination of moisture content of aggregates, wood and bricks used on
construction sites.
The purpose of measuring the moisture content of aggregate is to enable an
estimate to be made of the quantity of water contained within so that the
water added to concrete can be adjusted. Considering the determination of
moisture in wood, this is done in order to increase the quality of article made
from it. From research it was gotten that moisture in wood should be higher
then range of 20% or 25% for dense hardwood and 15% or 20% for
softwood and low density hardwood. Minimum moisture content of
thoroughly dried is 10% to 15%.
5.2. RECOMMENDATION
Since the significance of this study is to reveal to users and students the
procedure of measurement and control of moisture of aggregates to produce
good quality concrete. The followings are recommended:
64
Freshly delivery aggregate, especially fine aggregate during raining season
should be left unused after 24hours of delivery before use so that some of
the water it contained may be drained off before use.
The moisture content of aggregate delivered to the site for construction
purpose must be determined before it is used for any construction work to
regulate water content. It is best to put down a 100mm minimum thick layer
of concrete over the areas where the aggregate will be stored so that risen of
moisture from the soil could be avoided and to protect aggregate from
intermingling and contamination by other materials
Wood should be installed at moisture content levels as close as possible to
the average moisture it will experience in service. This minimizes the
seasonal variation in moisture content and dimension after installation,
avoiding problems such as floor bucking or cracks in furniture.
Brick must be adequately dried to the required or standard level of moisture
that is required to be present before construction proper.
Brick should be stored appropriately after casting under regular weather
condition.
65
5.4 SUGGESTION FOR FURTHER STUDIES
Based on findings, moisture, content can also be further study using other
method of determination /measurement. I suggest that the following methods
should be also examined.
i. Sipon-can method.
ii. Speedy method.
iii. Pycnometer method.
66
REFERENCES
BLACKLEDGE, G.F (1990) concrete practice. Britain: British Cement
Association.
BROOK, K.M & MURDOCK, L.J (1978): Concrete material and practice
London: Edward Arnold (publisher)
BROOK, J.J & NEVILLE, A.M (1994): Concrete Technology London:
Singapore: Longman Singapore publisher Limited
DERNCHER, K.N & HEINS, C.P (1981): Materials for Civil and Highway
Engineers U.S.A: Prentice Hall, inc. England clifts.
NEVILLE, A.M (1981): Properties of concrete (3rd Edition) London: Pitman
Publishing Limited.
ORCHARD, D.F (1990): Concrete Technology (vol 3) P [properties and
Testing of Aggregates. London: Applied Science Publisher
Limited.
SMITH, B.J (1978): Construction Science (volume 2). New York: Longman
Inc.
TAYLOR, J.B (1990): Plastering fifth Edition. England: Addison Wesley
Longman Limited.
TAYLOR, G.D (1994): Material in construction (2nd Edition). London
Longman Singapore Publisher (pte) limited.
67
WILSON, F. (1984): Building Material Evaluation Handbook. NEW York:
van nostrand Renhold Company Inc.
68
APPENDIX
Natural pit sand sample
Natural pit sand sample
69
Coarse aggregate sample
70
Parana(softwood)
Itare (Hardwood)
71
Arere(softwood
Eku( Hardwood)
72
Balsa (hardwood)
Mahogany (hard wood)
73
Mariana (softwood)
Brick Sample.
74