Basic Civil and Mechanical Engineering Unit I Construction Materials Presentation

Unit 1

Construction materials

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Bricks Stones Cement Mortar Sand Cement Concrete Bars Wood Plastics Download this material from :

Manufacture of bricks Preparation of brick earth.  Moulding of bricks  Drying of bricks  Burning of bricks 


Preparation of brick earth Loose soil which contains impurities, is removed for about 20 cm depth. Earth is then dug out from the ground, spread and weathering is done for a week time. The clay is then mixed with suitable ingredients by tilting the clay and ingredients up and down ina kiln. Water is added to clay to make the whole mass of clay homogeneous and plastic. •

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Moulding Mouldi ng of bricks bricks Hand Hand moul mouldi ding ng:: It is done in a rectangular box with open at top and bottom. Box is made up of wood or steel. Hand Ha nd mo moul uldi ding ng fu furt rthe herr cl clas assi sifi fied ed in into to,, (a) Table moulding (b) Ground moulding Table Tab le mou mouldi lding ng (a) Done by the experienced supervisor Bricks are moulded on the table and sent to next stage. (b) Ground Gro und Mou Mouldi lding ng Small portion is cleaned and leveled. Find sand is sprinkled over it. Mould is dipped in water and kept on the ground and the clay is pressed by hand Download this material from : •

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Machine Machin e mou mouldi lding: ng: Used Used in ma mass ss prod produc ucti tion on of bricks (huge quantity) Thes Thesee ma mach chin ines es cont contai ain n a rectangular rectangular opening of size equal to length and breadth of the brick. The tempered clay is placed in the machine. The The temp temper ered ed clay clay come comess out as through the opening under pressure, hence it is cut to the required shape. •

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Drying of bricks Bricks are staked in the yard with 8 to 10 bricks in a row. Bricks are dried for a period of 5 to 12 days. Some times bricks are dried by hot gases from kiln. But But arti artifi ficcia iall dryi drying ng pro produce ducess wa warp rpss on th thee bricks •

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Burning of bricks It imparts hardness and strength to bricks and makes them dense and durable. Burning should be uniform, because unburnt bricks remain soft and hence cannot carry loads. Overbur burnt bric ricks become brittle and break easily. Burning of bricks done in clamp or kilns. •

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Qualities of good bricks Well burnt, Sharp edges, copper coloured, free  from cracks Should give a good ringing sound  Bricks should not break when dropped from a  height of 1m Bricks should have a low thermal conductivity  The minimum crushing strength should be  3.5 N/mm2 Average weight of bricks should be 3 – 3.5 kg.  Download this material from :













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Building stones are obtained from rocks Rocks are classified into igneous rocks, sedimentary rocks and metamorphic rocks. Igne Igneou ouss rock rockss are formed by cool coolin ing g of th thee mo molt lten en ma mate terria ials ls beneath the earth’s surface. Stones from igneous rocks are harder.. harder Granite which is widely used in construction of building is a good example. Download this material from :

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Sedimentary rocks are formed by deposition of weat athe heri rin ng products on existing rocks. Deposits in laye ayers an and d when hen the load is applied along the layers these rocks easily split. Metamorphic rocks are formed in the change in character of the pre existing rocks. These rocks will also be hard, if the basic rock is igneous rock. Download this material from :

Quarry Quarrying ing of ston stones es  It is the process of extract ractiing stone blo loccks from existing rocks.  In general, it is done some depth bel below the the top surface of rock, where the effects of weathering are not found. Quarrying is done by digging, heating or wedging. wedging .  In soft rocks, like lime stone and marble stones are  obtained by digging, heating or wedging by hand tools. In hard and dense rocks, stones are obtained by  blasting using explosives. Download this material from :

Dressing of stones : Stones have irregular shape after quarrying  The process of cutting the stones to a regular  shape and size and the required surface finish is called dressing of stones.


Testing of stones : 

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Hardness test : Stone is tested by a pen knife which will not be able to produce a scratch on a hard stone. Acid Ac id te test st : Stone is kept in sulphuric acid and hydrochloric acid for a week time. The corners of the stones with high alkaline content turn roundish and loose particles will get deposited on its surface. Such stones are not suitable for smoky atmosphere.


Qualities of good stones 

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The crushing strength of stone should be greater than 100 N/mm2 Stones must be uniform in colour. Light coloured stones resist weathering action in a better way. When the stones are used for roads, it must be hard enough to resist wear and tear. A good building stone must have specific gravity greater than 2.2


Manufacturing of cement Cement is obtained by burning the mixture of  calcareous and argillaceous materials at a very high temperature. The calcined product is known as clinker  A small quantity of gypsum is added to the  clinker and is pulverised into very fine powder known as cement.  On setting, cement resembles a variety of sand stone in found portland in England and is therefore called Portland cement. Download this material from :



Types of cement Rapid Hardening cement   

It is similar to port land cement. It develops strength rapidly This cement is used where high strength is required at initial stages.

Quick setting cement  

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This cement sets very quickly. It is due to reduction of gypsu psum content in no norm rmaal portland cement. It is used for underwater construction. Download this material from :

Types of cement Coloured cement 

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It contains 5 to 10 percent of pigment with normal portland cement for colouring. This is used for aesthetic purposes

White cement   

The colour of cement is white It has the same properties of portland cement It is used for architectural purposes and manufacturing coloured concrete, flooring tiles etc., Download this material from :

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Types of cement Masonry cement It ha hass grea greatt pla lassti ticcit ity y, workabi kabili lity ty an and d wat ater er  retentivity It is used for masonry constructions in making  mortars and plasters.


Qualities of a good cement The colour should be uniform  Cement should be cool when felt with hand.  If a small quantity of cement is thrown in to a  bucket of water, it should sink. Cement should be free from lumps.  The initial setting setting time should not be less than 30  minutes an and d the fina nall setting time should be around 10 hours. Download this material from :

Mortar is the term used to indicate a paste prepared by adding water to a mixture of binding material (cement or lime) and the fine aggregate.

Classification of mortar : Bricklaying mortar:  It is used for brickwork and walls. Depending upon the working conditions and the type of  construction , the binding materials for the mortar is decided. Finish Fin ishing ing mor mortar tar : Thes Thesee mo mort rtar arss in incl clud udee comm common on plas plaste teri ring ng wo work rk an and d  ornamental ornamental effects. eff ects. Cement or lime is use used as the bindi nding material rial for  ordinary plastering mortar. Download this material from :

Special mortars Fire Fir e resist resistant ant mor mortar tar : It is prepared by adding aluminous cement to the finely  crushed powder of fire bricks. The usual proportion is one part aluminous cement to  two parts fire brick powders. Light weight mortar: It is prepared by adding materials such as saw dust,  wood powder, etc.,  Other materials could be asbestos, fibres, coir etc., Thi hiss morta rtar is sued sued fo forr soun sound d proo roof an and d hea heat proo roof  construction. Download this material from :

Uses of mortar 

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To bind the building units such as bricks, stones, etc., into a solid mass. To carryout plastering work on the exposed surfaces of masonry. To form even and soft bedding layer for building layer. To fill up the cracks detected in the structure during maintenance process etc.,


Classification of sand (i) Natural sand (ii) Artificial sand Natu Na tura rall sa sand nd  It is the sand carried away by river water and quarried from river bed. Artif Ar tific icia iall sa sand nd  Produced by crushing and breaking stones into different sizes of stone in a crushing plant.


Qualities Qualiti es of good good sand sand Sand should be clean, hard, durable and dry.  Free from mica, chemical salts, organic and inorganic  impurities and other foreign matters. Uses of sand : It is used for making mortar and concrete  It is used as filling in the basement of buildings.  Used as the binding material on the top of bituminuous  road.


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DEFINI DEFI NITI TION ON : It is a mixture of cement, sand, crushed rock and water which when placed in the skel keleton forrms an fo and d al allo low wed to cur cure beco ecomes hard like a stone.

Uses Us es of con concre crete: te: 

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It is used for the construction of Reinfo Reinforce rced d Cemen Cementt Co Concr ncrete ete fla flatt roof roof slabs. Coloured concrete is used for ornamental finishes in buildings, pack lanes, separating lines of road surfaces. Light weight concrete is used in multi storey constructions. Download this material from :

Rein Re info forc rced ed Ce Ceme ment nt Co Conc ncre rete te (R (RCC CC): ):  Plain concrete is very weak in tension and cannot be used in cons constr truc ucti tion on of roof roof sla slabs, bs, bea beams etc.,  Because the bottom fibres of them are subjected to tensile stresses.  A combination of concrete and steel is known as Reinforced Cement Concrete and widely used.


Advantages of Reinforced Cement Concrete : It is versatile building material can be used for  casting members of any shape. It has good fire resistance and weathering  actions. Easy to construct  RCC is tough and durable 


Steel contains carbon upto a maximum of 1.5 percent. Based on the carbon content, steel are classified into,  Low carbon steel (Mild steel) with carbon content 0.25 percent.  Medi Medium um carb carbon on or medium hard steel with carbon content between 0.25 – 0.70 percent  High carbon steel or hard steel having carbon content 0.70 – 1.5 percent.


Uses of Low carbon steel (Mild steel): Low carbon or mild steel is used in structural works such  as trusses, angles and plates. It is also used in RCC works as plain or twisted rods.  Uses of Medium hard steel: It is used in the manufacture of rails, chisels, hammers,  boiler plates etc. Uses of hard steel : It is used in earth moving or mining equipments.  Used for manufacturing cutting steel 


Torsteel rods : Torsteel rods are twisted or  torsioned deformed rods. Ordinary steel rods are  round plain bars made of mild steel. Both plain bars and tor steel  rods are used in RCC roof slabs, beams, columns.




Wood rendered suitable for use as structural materials by sawing and cutting is called as a timber. Season Sea soning ing of timb timber: er: It is the process of reducing the moisture in the timber.  Seasoning of the timber reduces timber getting  decomposed or decayed. It is done by air seasoning , boiling water seasoning or  kiln seasoning. Def efec ects ts in ti timb mber er : Timber used in construction should be free from cracks,  knots, worm holes, upsets etc. Download this material from :

Advantages of timber in cons co nstr truc uctio tion n: Timber is light, strong and  durable. It takes shocks and impacts  without rupturing. It offers a good electrical  resistance. It has good sound absorption and  thermal insulation characteristics.


Uses Us es of tim timbe berr Timbers are used for manufacturing  structural members such as beams, lintels and joints. It is used used fo forr ma manu nufa fact ctur urin ing g doo oorr an and d  window frames and panels. It is used for flooring also in auditorium  It is used for making partitions, paneling  etc. Used for interior decoration 


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Plywood is obtained by gluing three more mo re vene veneer ers. s. Veneers are thin sheets of wood. The The vene veneer erss are are obt obtai aine ned d as slice licess from different woods. The are placed in different layers in any odd number, the grains succ su cces essi sive ve ve venee neers rs being at right angles The layers thus arranged are pressed to form a plywood


Advantage Advant agess of plywoo plywood d: Plywood are light and strong  Available in different sizes.  Not affected by moisture and temperature. Hence less  shrinkage or expansion. Elegant appearance.  Uses of plywood : Used in manufacturing the partitions.   Sliding doors and cabinet doors. Ward robes and cup boards   False construction Download this material from :

Substances which becomes plastic on the application of heat and pressure are called plastics. Thermo plastics : Thermo plastics become soft on heating and hard on cooling.  It can be melted and solidified a number of times without much change in their properties. Eg : Polyvinyl chloride, polythene, perpex Thermosetting plastics : Thremosetting plastics are moulded under heat and pressure  to form objects. The product obtained possesses totally different appearance,  different chemical and physical properties. Resistant to further application of heat.  Eg : phenol formaldehyde, urea formaldehyde Download this material from :

Uses of plastics as a building material : Used for manufacturing door and window  frames. Used for preparing insulating materials.  Used for manufacturing lighting fixtures.  They are used for making wall covering, floor  covering. Foamed plastics are used as right slabs. 


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K.V. Natarajan, Dr. M. Kantha basu, N. Venkatesan, N. Vasudevan, Basic Civil and Mechanical Engineering, Dhanalakshmi Publications, 2011. G. Shanmugam, M.S. Palanichamy, Basic Civil and Mechanical Engineering, Tata McGraw Hill publishers, 2010.


Prepared by A.R. Pradeep Kumar Associate Professor / Mechanical Mechanical

Email : [email protected] Website : www.arpradeep.tk


Basic Civil and Mechanical Engineering Unit I Construction Materials Presentation

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