Materials of Constructions in Civil

Materials of Constructions in Civil

1. Traditional Materials
The building materials such as stones, bricks and timber are called traditional building materials since these materials are used from the early ages of civilization. Cement, cement-mortar and cement-concrete are also grouped under traditional materials although they are of recent origin compared to stones and bricks. The properties and uses of some of the most commonly used traditional building materials have been discussed here.

a. Stones
Stones are obtained from rocks. A rock represents a definite portion of earth’s surface. Process of taking out stones from natural rock beds is known as quarrying. The term quarry is used to indicate the exposed surface of natural rocks. Stones, thus obtained, are used for various engineering purposes.

Properties: A good building stone should have the following qualities.

1. Crushing Strength: For a good structure stone, the crushing strength should be greater than 100 N/mm2.
2. Hardness: For a good building stone, the coefficient of hardness should be more than 17.
3. Fracture: For a good building stone, its fracture should be sharp, even and clear.
4. Percentage wear: The percentage wear should be equal to or less than 3%.
5. Resistance to fire: Minerals composing stone should be such that shape of stone is preserved when a fire occurs.
6. Water absorption: For a good stone, percentage absorption by weight after 24 hours should not exceed 0.6.
7. Specific gravity: A good building stone should have a specific gravity more than 2.7. Compact and less porous building stones will have higher specific gravity.
8. Durability: A good build stone possesses higher resistance against the action of weathering agents. Durability is affected by chemical composition, resistance to atmospheric agents, physical structure etc.
9. Appearance: Stones which are used for face work should be decent in appearance and they should be capable of preserving their colour uniformly for a long time.
10. Seasoning: Stones should be well seasoned before putting into use i.e., they should be free of moisture content (quarry sap). Stones should be dried or seasoned before they are used in structural work.

Uses of Stones:
1. Stones are used as a construction material for foundations, walls, columns and lintels.
2. Stones are used for face-work of buildings to give good appearance.
3. Thin stone slabs are used as roofing and flooring material.
4. Crushed stones are used for production of cement concrete.
5. Crushed stones are also used as ballast for railway track.
6. Aggregate of stone is used as a road metal.

b. Bricks: Bricks are obtained by moulding clay in the rectangular blocks of uniform size and then by drying and burning these blocks. Bricks are very popular as they are easily available, economical, strong, durable and reliable. They are also reasonably heat and sound proof. Thus, at places where stones are not easily available, but if there is plenty of clay, bricks replace stones.


Properties of bricks: Good bricks which are used as building material should possess the following qualities.
1. Bricks should be uniform in shape and should be of standard size.
2. Bricks should be table moulded, well burnt in kilns, copper coloured, free from cracks and with sharp and square edges.
3. Bricks should give clear ringing sound when struck with each other.
4. Bricks when broken should show homogeneous and compact structure.
5. A brick should not absorb more than 15% of its weight of water when kept immersed for 24 hours.
6. The crushing strength should not be less than 5.5 N/mm2.
7. Bricks should be sufficiently hard such that no impression is left when scratched with finger nails and they should be free of soluble salts.
8. A brick should not break when dropped from a height of about one metre.

Uses of Bricks:
1. Bricks are extensively used as a leading material of construction.
2. A fire brick (Refractory brick) is used for lining the interiors of ovens, chimneys and furnaces.
3. Broken bricks are used as a ballast material for railway tracks, and also as a road metal.
4. Bricks are extensively used for construction of load-bearing walls and partition-walls.
5. Bricks are also used for face-work when artistic effect is required.

c. Timber:
The word timber is derived from ‘Timbrian’ which means to build. Timber thus denotes wood which is suitable for building construction, carpenting or other engineering purposes. When it forms part of a living tree it is called ‘Standing timber’, when felled it is known as ‘Rough timber’ and when cut in to different forms such as planks, beams etc., it is known as ‘Converted timber’.

Properties of timber
1. Strength: A good timber should have high strength in bending, shear and direct effects so that it can be used as a structural member such as beam or column.
2. Appearance: A good timber possesses fine and even texture, close grains and shining dark appearance.
3. Durability: A good timber should be durable and capable of resisting the actions of fungi, insects, chemicals and physical agencies.
4. Hardness and Toughness: A good timber will be hard and capable of resisting shock loads.
5. Seasoning: Seasoning is the process of removal of water from the freshly cut timber when is present in the form of sap and moisture. A good timber is to be well seasoned before using it for any engineering purposes.
6. Resistance to fire and thermal expansion: A good timber should have high resistance to fire. Timber has very low coefficient of thermal expansion parallel to grains and is a bad conductor of heat.
7. Workability: A good timber should be easily workable and should not clog the saw and can be planed easily.
8. Defects: A good timber should be free from serious defects like knots, flaws, shakes etc.

Uses of Timber:
1. For making doors, windows and ventilators.
2. Used as flooring and roofing material.
3. Used for making furniture.
4. Used in making agricultural implements.
5. Used in the manufacture of sport goods, musical instruments etc.
6. Used in making railway coaches, wagons, buses, boats etc.
7. Used in making sleepers for railways, fencing poles, electric poles, footways, bridge floors, temporary bridges etc.
8. Soft wood is used for manufacture of paper, card-boards, walls paper etc.

d. Mortar:
The term mortar is used to indicate a paste prepared by adding required quantity of water to a mixture of binding material and sand. The most common binding material used in the preparation of mortar is cement. Such a mortar is called cement-mortar.

Properties of mortar
1. Strength: The compressive strength of cement-mortar varies from 1 N/mm2 to 10 N/mm2 depending upon mix proportion of cement and sand and water added to it.
2. Durability: Good cement-mortar can effectively withstand the adverse effects of weathering agents such as rain, wind and sun light.
3. Impermeability: Mortars should be impervious and act as a water-tight layer.
4. Shrinkage: Mortar exhibits tendency to shrink during setting process and likely to develop hair-line cracks. Mortars with rich cement mix are prone to high shrinkage.
5. Binding strength: When water is added to the dry mix of cement and sand, the hydration process of cement starts and cement binds the sand particles and the surrounding surfaces of masonry and concrete. A good mortar possesses high binding strength.

Uses of mortar
1. Mortar is used as a binding material for brick and stone masonry constructions.
2. Mortar is used to carry out pointing and plastering work on exposed surfaces of masonry.
3. Mortar is used to provide fine finish to concrete works.
4. Mortar is used for decorative finish to masonry walls and roof slabs.
5. Mortar is used as a filler material in ferro-cement works.

e. Cement concrete
Cement concrete is an artificial product obtained by hardening of the mixture of cement, sand, gravel and water in pre-determined proportions. The hardening of cement-concrete is due to chemical reaction between cement and water and the process is also called ‘setting’.

Properties of cement-concrete
Properties of concrete are different when it is in plastic stage (green concrete) and hardened stage.

Properties of Green Concrete:
1. Workability: The workability of a freshly prepared concrete is the ease with which it can be mixed, placed, compacted and finished without affecting homogeneity.
2. Segregation: A good concrete is a homogeneous mixture of cement, sand, coarse aggregates and water. Segregation during mixing, placing and compacting affects strength, durability and water tightness.
3. Bleeding: Bleeding is the separation of water cement slurry from coarse and fine aggregates either due to excessive quantity of water in fresh concrete or due to excessive vibration during compaction process. Bleeding of concrete causes formation of pores and reduces compressive strength.
4. Harshness: Harshness of concrete is due to use of poorly graded aggregates in concrete mix. A harsh concrete is porous and difficult to get smooth surface finish.

Properties of hardened Concrete
1. Strength: Hardened concrete should have high compressive strength. Compressive strength is the most important parameter considered in the design of concrete structures.
2. Durability: Concrete should be capable of withstanding the adverse effects of weathering agents such as wind and water. In addition, it should resist temperature variation, moisture variation, freezing and thawing.
3. Impermeability: Hardened concrete should be impermeable or water-tight. This property of concrete is considered in the construction of water tanks and bins.
4. Resistance to wear and tear: Hardened concrete should be capable of with standing abrasive action during its usage. When concrete is used as a flooring material, or for construction of cement concrete roads, it should withstand abrasive action.

Uses of Cement Concrete
1. It is used for making Reinforced Cement Concrete (R.C.C.) and Prestressed Cement Concrete (P.S.C.).
2. It is used for mass concrete works such as dams and bridges.
3. It is used for making electric poles, railway sleepers and high rise towers.
4. It is used for the construction of silos and bunkers.
5. It is used for the construction of water tanks and under water construction.
6. It is used for the construction of road pavements and air port pavements.
7. It is used for construction of arches and ornamental structures.
8. It is one of the best universally accepted construction material and used in various civil Engineering works.

Reinforced Cement Concrete (R.C.C.)

Plain concrete can withstand very high compressive loads. But it is very weak in resisting tensile loads. Steel, on the other hand can resist very high tensile force. Hence, steel is embedded in concrete whenever tensile stresses are expected in concrete. Such a concrete is called ‘Reinforced Cement Concrete’.

Properties of R.C.C.
1. R.C.C. is highly economical when compared to other engineering materials.
2. R.C.C. is durable and can effectively resist moisture variation and temperature variation.
3. R.C.C. is a fire resistant construction material.
4. Water-tight structures such as water tanks can be constructed of R.C.C.
5. R.C.C. can be moulded to any shape and size before setting and hardening of concrete.

Uses
1. R.C.C. is used for construction of structural elements such as beams, columns and slabs.
2. R.C.C. is used for the construction of water tanks, storage bins, bunkers, tall chimneys, towers etc.,
3. R.C.C. is used in making raft foundations and pile foundations.
4. R.C.C. is used in the construction of bridges, marine structures, aqueducts, high rise buildings and many other civil engineering works.

• Stones, bricks, timber and concrete are grouped under traditional building materials
• Stones are characterised by high crushing strength, high hardness and very high durability. Stones are used as a construction materials for foundations, walls, columns, roofing & flooring material and as aggregate in production of concrete
• Bricks are produced by moulding clay in the rectangular blocks. They are economical and reliable building material. Bricks are extensively used as a leading material of construction and at places where stones are not easily available, bricks replace stones.
• Timber denotes wood which is suitable for building construction. A good timber is characterised by high strength in bending and shear and capable of resisting shock loads. It is extensively used for making door and window frames, trusses and furniture. It is also used as a material for temporary structures such as scaffolding and temporary bridges.
• Mortar is prepared by adding water to mixture of cement and sand. A good mortar possesses high binding strength. It is used as a binding material for masonry constructions.
• Concrete is produced by mixing cement, sand gravel and water in definite proportions. It is characterised by high compressive strength and resistance to wear and tear. It is used for mass concrete works in dams and bridges, for making Reinforced Cement Concrete and Prestressed Cement Concrete and other Civil engineering works.
• Steel is embedded in concrete whenever tensile stresses are expected in concrete. Such a concrete is called reinforced cement concrete. R.C.C. is used for construction of structural elements such as footings, columns, beams and slabs.

Materials of Constructions

Materials of Constructions

Several materials are required for construction. The materials used in the construction of Engineering Structures such as buildings, bridges and roads are called Engineering Materials or Building Materials. They include Bricks, Timber, Cement, Steel and Plastics.
The materials used in Civil Engineering constructions can be studied under the following headings.
1. Traditional materials
2. Alternate building materials
3. Composite materials
4. Smart materials
It is necessary for an engineer to be conversant with the properties of engineering materials. Right selection of materials can be made for a construction activity only when material properties are fully understood.

Some of the most important properties of building materials are grouped as follows.

Definitions
Density: It is defined as mass per unit volume. It is expressed as kg/m3.

Specific gravity: It is the ratio of density of a material to density of water.

Porosity: The term porosity is used to indicate the degree by which the volume of a material is occupied by pores. It is expressed as a ratio of volume of pores to that of the specimen.

Strength: Strength of a material has been defined as its ability to resist the action of an external force without breaking.

Elasticity: It is the property of a material which enables it to regain its original shape and size after the removal of external load.

Plasticity: It is the property of the material which enables the formation of permanent deformation.

Hardness: It is the property of the material which enables it to resist abrasion, indentation, machining and scratching.

Ductility: It is the property of a material which enables it to be drawn out or elongated to an appreciable extent before rupture occurs.

Brittleness: It is the property of a material, which is opposite to ductility. Material, having very little property of deformation, either elastic or plastic is called Brittle.

Creep: It is the property of the material which enables it under constant load to deform slowly but progressively over a certain period.

Stiffness: It is the property of a material which enables it to resist deformation.

Fatigue: The term fatigue is generally referred to the effect of cyclically repeated stress. A material has a tendency to fail at lesser stress level when subjected to repeated loading.

Impact strength: The impact strength of a material is the quantity of work required to cause its failure per its unit volume. It thus indicates the toughness of a material.

Toughness: It is the property of a material which enables it to be twisted, bent or stretched under a high stress before rupture.

Thermal Conductivity: It is the property of a material which allows conduction of heat through its body. It is defined as the amount of heat in kilocalories that will flow through unit area of the material with unit thickness in unit time when difference of temperature on its faces is also unity.

Corrosion Resistance: It is the property of a material to withstand the action of acids, alkalis gases etc., which tend to corrode (or oxidize).

• Brick, stone, timber, cement, steel and plastics are the common materials used in constructions.
• The most common properties of building materials are grouped into physical properties, mechanical properties, thermal properties, chemical properties, optical properties, acoustical properties, and physio-chemical properties

Construction Management

Construction Management

Management is the science and art of planning, organising, leading and controlling the work of organisation members and of using all available organisation resources to reach stated organizational goals.

Construction management deals with economical consumption of the resources available in the least possible time for successful completion of construction project. ‘Men’, ‘materials’, ‘machinery’ and ‘money’ are termed as resources in construction Management.

Objectives of Construction Management :
The main objectives of construction management are,
• Completing the work with in estimated budget and specified time.
• Maintaining a reputation for high quality workmanship
• Taking sound decisions and delegation of authority
• Developing an orgnisation that works as a team.

Functions of Construction Management
The functions of construction Management are
(a) Planning
(b) Scheduling
(c) Organising
(d) Staffing
(e) Directing
(f) Controlling
(g) Coordinating

(a) Planning:
It is the process of selecting a particular method and the order of work to be adopted for a project from all the possible ways and sequences in which it could be done. It essentially covers the aspects of ‘What to do’ and ‘How to do it’.

Importance of planning :
• Planning helps to minimize the cost by optimum utilization of available resources.
• Planning reduces irrational approaches, duplication of works and inter departmental conflicts.
• Planning encourages innovation and creativity among the construction managers.
• Planning imparts competitive strength to the enterprise.


b) Scheduling : Scheduling is the fitting of the final work plan to a time − scale. It shows the duration and order of various construction activities. It deals with the aspect of ‘when to do it’.

Importance of scheduling : Scheduling of the programming, planning and construction process is a vital tool in both the daily management and reporting of the project progress.

c) Organising : Organising is concerned with decision of the total construction work into manageable departments/sections and systematically managing various operations by delegating specific tasks to individuals.

d) Staffing : Staffing is the provision of right people to each section / department created for successful completion of a construction project.

e) Directing : It is concerned with training sub ordinates to carryout assigned tasks, supervising their work and guiding their efforts. It also involves motivating staff to achieve desired results.

f) Controlling : It involves a constant review of the work plan to check on actual achievements and to discover and rectify deviation through appropriate corrective measures.

g) Coordinating : It involves bringing together and coordinating the work of various departments and sections so as to have good communication. It is necessary for each section to aware of its role and the assistance to be expected from others.

Importance of Construction Management :

1. Proper management practices invariably lead to “maximum production at least cost”. A good construction management, results in completion of a construction project with in the stipulated budget.
2. Construction management provides importance for optimum utilization of resources. In other words, it results in completion of a construction project with judicious use of available resources.
3. Construction management provides necessary leadership, motivates employees to complete the difficult tasks well in time and extracts potential talents of its employees.
4. Construction management is beneficial to society as the effective and efficient management of construction projects will avoid, escalation of costs, time overrun, wastage of resources, unlawful exploitation of labour and pollution of environment.

Planning, Scheduling and Construction Management in civil

Planning, Scheduling and Construction Management in civil
The construction industry plays a significant role in the development of national economy. Almost half of the total outlay in any Five year plan is utilized for construction activities which constitute an integral part of all development projects. During the last four decades, the construction industry in India has undergone large scale mechanization with rapid changes and advancement in construction practices as well as in the management of construction works. The term ‘Construction’ is no longer limited only to the physical activities involving men, materials and machinery but covers the entire gamut of activities from conception to realization of a construction project.

Impact of Infrastructural developments on the economy of the country

Impact of Infrastructural developments on the economy of the country

The term infrastructure is used to denote the conditions which are available for economic development of a region. In other words infrastructure can be defined as the facilities to be provided by the state or central government or local administration for overall development of a region. The facilities include power generation, transportation, health, education, water and sanitation and other public utilities.
The investments made on infrastructural developments have a profound impact on the economy of the country. Some of the effects of investment made on infrastructure is given below.

• Investment on infrastructral facilities result in increased job opportunities for both skilled and unskilled and literate and illiterate people. Eg: Construction of new roads, bridges & canals provide employment to large number of poor people.
• The creation of better infrastructure in a region motivate entrepreneurs to establish their own industries, service centers, commercial establishments etc. This will open up job opportunities to a number of unemployed people in the region. The improvements in job opportunities will have positive effect on economy.

Scope of Civil Engineering

Scope of Civil Engineering

Civil Engineering is the oldest branch of Engineering next to Military Engineering. It involves planning, design, construction and maintenance of structures such as bridges, roads, canals, dams, tunnels and multi-storeyed buildings.
Shelter is the basic need of civilization. The huts built with bamboos and leaves can be taken as the early civil Engineering Constructions carried out to satisfy the needs for shelter. Over the years there has been a tremendous growth in the field of civil Engineering to provide quality houses which are safe, functional, aesthetic and economical.

Flats and apartments are constructed in urban areas to provide shelter to large number of people. Multi storeyed buildings and sky−scrapers are planned and constructed to provide office space, shopping−malls, cyber centers, hotels and restaurants etc.

Irrigation is defined as the artificial application of water to land for the purpose of raising crops. Civil Engineering gives vast scope for irrigation by constructing barrages, dams, canals and distributaries. Vast areas of dry land have been successfully irrigated and green revolution has become a reality in India.

Providing better transportation facilities is also a part of civil Engineering. Good network of roads, highways & expressways are necessary for movement of men and materials. Railways, Airways and Waterways are needed for overall development of any country.


Water is an important need for all living beings. Potable water supply to the towns and cities is a thrust area in Civil Engineering. Natural water available in lakes and rivers is not suitable for drinking without proper treatment. Hence big water treatment plants have been constructed and operated to supply potable water to the public. In addition, waste water generated in the city has to be taken out and disposed after providing suitable treatment.

Flood control and environmental protection are other areas where in Civil Engineering has an important role to play. Dams and levees are constructed to mitigate floods. Waste Water Treatment plants are constructed to prevent pollution of surface and ground water sources.

Role of Civil Engineers

Role of Civil Engineers

A Civil Engineer is one who deals with the planning, designing, construction and maintenance of different types of Civil Engineering works. He should be competent in various fields such as surveying, analyzing, estimating, construction scheduling and construction management.
A Civil Engineer will involve in various Engineering activities such as

• Surveying and preparation of estimates.
• Planning and designing and construction of houses, apartments, office − buildings, commercial establishments and factory building.
• Planning and design of transportation facilities such as highways and Railways.
• Construction of ports and harbours, Railway stations, bus and truck terminals, airports and helipads.
• Construction of dams and canals for irrigation, drinking water supply for flood control purposes.
• Planning, design and construction of pollution control facilities such as sewage treatment plants.