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GYANMANJARI INSTITUTE OF TECHNOLOGY

CHAPTER 6 BUILDING MATERIALS

INTRODUCTIONSTONEBRICKLIMECEMENTTIMBERSANDAGGREGATESMORTARCONCRETEBITUMEN

STONE:-Stone is a natural engineering material.Stones are derived from rocks, which form the earths crust and have no definite shape and structure but it can be a mixture of two or more materials.

Requirements of StoneStructureAppearance & Color:-uniform color Texture:-arrangement of its constituent minerals.Specific gravity:- should have sp. Gravity in between 2.4 to 2.7.Water absorption:- Not more than 5%. Durability:- Depends upon chemical compositionStrength:- Crushing strength more than 100N/mm2.Hardness:-Better resistance against abrasion.Facility of Working and Dressing

Uses of Stone

They are used in hydraulic structures like dams and bridges.They are used in retaining wall masonry to retain soil.They are used as road metal in road construction.They are used as ballast for permanent way in railways.They are used to make concrete in the form of coarse aggregate.Properties of StoneSilicious rocks are hard and durable. They are not easily affected by weathering actions.Argillaceous rocks may be dense and compact or they may be soft.The Durability of calareous rocks will depend upon the constituents present in surrounding atmosphere.Marble and quartzite have compact crystalline structure.Igneous rocks contain many minerals. Various minerals having wide range of different distinctive characteristics. BrickRequirements of BricksThe colour of the brick should be red or copper and uniform.It should be well burnt in kilns.The surface should be even and free from cracks.The edges should be sharp.

Composition of Good brick earth (1)Alumina (Al2O3):It is the chief constituent of a good brick earth. A content of about 20% to 30% is necessary to form the brick earth of a good quality. It imparts plasticity to the earth so it helps in the moulding of the brick earth.(2)Silica (SiO2):It exists in the brick earth either free or combined. As free sand it is mechanically mixed with clay and in combined form it exists in chemical composition with alumina. A good brick earth should contain about 50% to 60% of silica. (3)Lime(CaCO3):A small quantity of lime not more than 5% is desirable in good brick earth. It should be present in very fine state, because even small particles of size of a pin-head can result in the flaking of the brick. (4)Oxide of Iron (Fe2O3):Iron oxide performs two functions, first it helps in fusing of the sand like lime and second it provides the red color to the bricks. It is kept below 5 to 6% because excess of it may result in the dark blue or black color of brick.(5)Magnesia: It is used to provide a yellow tint to the bricks. Its content is only about 1% or less.

Types of BricksConventional / Traditional bricks : Size 23 cm x 11.4 cm x 7.6 cmStandard / Modular : Size : 19 cm x 9 cm x 9 cmClassification of Bricks (1) First class bricks:These first class bricks are table moulded and of uniform shape and they are burnt in kilns. The surfaces and edges of the bricks are sharp, square, smooth and straight. They comply with all the qualities of good bricks. These bricks are used for important work of permanent nature.(2) Second class bricks:The second class bricks are ground moulded and they are burnt inkilns. The surface of the second class bricks is slightly rough and shape is also slightly regular. These bricks may have hair cracks and their edges may not be sharp and uniform. These bricks are commonly used at places where brickwork is to be provided with a coat of plaster.(3) Third class bricks: These bricks are ground-moulded and they are burnt in clamps. These bricks are not very hard and they have rough surfaces with irregular and blunt edges. These bricks give dull sound when they are struck together. They are used for unimportant works, temporary structures and at places where rainfall is not heavy.(4) Fourth class bricks:These are overburnt bricks with irregular shape and dark colour. These bricks are used as aggregate for concrete infoundations,brick floors,surkhi, roads, etc. because of the fact that the overburnt bricks have a compact structure and hence they are sometimes found to be stronger than even the first class bricks.

Uses of brickBricks are used in wall masonry construction of buildingUsed in brick lintel constructionBats of brick are used in concrete in foundation work Properties of bricksThey are durable.They are low cost material.They possess good strength.They are easily available.Brick are light in compared to stones.Lime Requirement of limeit should set easily.it should have low shrinkage.it should not contain impurities.It should be moisture resistantIt should slake easily with water.Types of lime (1) Fat Lime/Pure Lime:- Fat lime is also known as pure lime, white lime or rich lime, this is manufactured using the purest form of the limestone. It is popular with its name as fat lime since its volume is increased to about 2 to 2.5 times its originally volume after getting slaked. (2) Hydraulic Lime:This lime has the hydraulic property, means it can set under the water also. It contains clay and some amount of ferrous oxide also. This is also known as water lime. Depending upon the amount of clay hydraulic lime is classified into further three categories: (a) Feebly hydraulic lime (b) Moderately hydraulic lime (c) Eminently hydraulic limeIncrease in the percentage of clay makes the slaking difficult and thus increases the hydraulic property of lime. With about 30 per cent of clay lime resembles the color of cement. The color of fat lime is not white therefore fat lime looks more sanitary than the hydraulic lime.(3) Poor Lime:Poor lime contains more than 30 percent of clay therefore it is also known as impure lime. It slakes very slowly and also does not dissolve into water. It has poor binding property and its color is muddy white.This lime forms very poor mortar and so such lime can be used for inferior types of work or at places where good lime is not available.

Uses of lime Lime is uses in the treatment of water and waste water.It is used in the manufacture of glass, refractory, sand lime bricks and paints.It is used as lime mortar for masonry work of buildings.It is used for plastering and white washing of buildings.It is used as lime concrete to make water proof structure.

Properties of limeIt has good workability.It stiftens quickly.It has low shrinkage.It has good resistant to moisture.Lime possesses good plasticity.

Cement Requirements of cementCement should Cement should not possess of alumina which may reduce strength. not contain alumina in excess as it weakens the cement.A very small amount of sulphur is added in cement to make sound cement.It should found cool when touch by hand. it should be in fine powder form while checking with first finger and thumb.

Functions of Cement Ingredients:Lime (CaO):This is the important ingredient of cement and I s proportion is to be carefully maintained. The lime in excess makes the cement unsound and causes the cement to expand and disintegrate. On the other hand, if lime is in deficiency, the strength of cement decreases and it causes cement to set quickly.Silica (Si02):This is also an important ingredient of cement and it gives or imparts strength to the cement due to the formation of dicalcium and tri calcium silicates. If silica is present in excess quantity, the strength of cement increases but at the same time.Alumina (AI203):This ingredient imparts quick setting property to the cement. It acts as a flux and it lowers the clinkering temperature. However the high temperature is essential for the formation of a suitable type of cement and hence the alumina should not be present in excess amount as it weakens the cement.Calcium sulphate (CaS04):This ingredient is in the form of gypsum and its function is to increase the initial setting time of cement.Iron oxide (Fe203):This ingredient imparts color, hardness and strength to the cement.Magnesia (MgO):This ingredient, if present in small amount, imparts hardness and color to the cement. A high content of magnesia makes the cement unsound.Sulphur (S):A very small amount of sulphur is useful in making sound cement. If it is in excess, it causes cement to become unsound.Alkalis:The most of the alkalis present in raw materials are carried away by the flue gases during heating.

Types of cementOrdinary portland cement(opc)Rapid hardening portland cementQuick setting cementPozzuolana portland cementLow heat cementBlast furnace cementWhite cementSulphate resisting cementColoured cement

Uses of cementIt is used in making joints for drains ,pipes.It is used to prepare RCC structures of building by using reinforcement with cement concrete. it is used in construction of buildings, bridges, tanks, domes, flyovers, dockyard etc.It is used to prepare cement mortar for building construction works like masonry, plaster, painting, flooring etc.It is used to prepare cement concrete for various construction works.Properties of cementPhysical properties of cementMechanical properties of cementChemical compositionFinenessSoundnessSetting of cement

Timber Requirements of timberIt should be dense.It should have uniform texture.It should have dark uniform color.It should be workable, good machinability.The medullary rays should be compact.Types of TimberNatural timber babul, oak, pine, mango, sal, teak, neem, palms, chir.Industrial timber veneers, plywoods, fiberboards, impreg timber, compreg timber. UsesRailway sleepers, bridges, pipes.Furniture, decorative pieces, doors.Packing material, piles, cart wheels.Poles, pen, rafter.Roofs, partition walls, boats etc. Properties of timberIt has low heat conductivity.It has small bulk density.It is relatively high strength.It is susceptible to decay.It is susceptible to flame.SandRequirements of sandIt should be clean.It should be well graded.Maximum permissible clay content is 3 to 4% in sand.It should contain sharp, angular grains.It should not contain salts which attract moisture from the atmosphere.Types of sandNatural natural sand is obtained from pits, river beds and sea beds.Artificial artificial sand is formed by decomposition of sandstone due to various weathering effects.

UsesSand is useful in various construction activities like masonry work, plaster work, flooring and concrete work.Sand is used in cement mortar, plan cement concrete , reinforced cement concrete and prestressed concrete as key ingradient in building construction. Properties of sandIt is naturally available materialIt is durableIt mix with binding material easilyIt has shiny lusterIt is of whitish brown color. AggregatesRequirements of AggregatesAggregates should be sufficiently strong.Aggregate surface should be rough and free form cracks.Aggregate should have good soundness.Aggregate should have good adhering with binding material.

TypesFine aggregates Size of aggregate is 4.75 mm or less is termed as fine aggregates.Coarse aggregates Size of aggregates 80mm to 4.75 mm is known as course.UsesFine aggregates are used to prepare cement mortar, lime mortar and cement concrete. Course aggregates are used to prepare cement concrete bituminous pavement, rigid pavement etc.They are used in construction of beams, columns, slab, lintel etc.Properties of aggregatesThey are insoluble in water.They are of moderate weight.They are strong and durable.They have resistance to scratches.They have resistance to corrosion and decay.Mortar Requirements of mortarIt should have good adhesion with bricks, stones.It should resist penetration of rain water.It should be cheap, durable, and workable.It should be set quickly.The joints formed by mortar should not develop cracks.TypesAs per type of binding material. like cement, lime, gauged, gypsum, surkhi.As per nature of application.As per density of the mortar.Special mortar.Uses To bind the bricks or stones firmly in wall construction work.They are used in plaster work as finishing material to provide weather resistance joints of masonry work are covered by plaster work. White wash and color are applied on plastered surface easily.Properties of mortarMobility.Place ability.Water retention

ConcreteConcrete is a mixture of cement/lime, sand, crushed stone, water.TYPES OF CONCRETE 1. Plain cement concrete 2. Reinforced cement concrete 3. Precast concrete 4. Prestressed concrete Properties of concreteWorkabilityStrengthDurabilityDimensional stabilityBitumenBitumen is an essential component of any pavement and is used widely throughout the world. It can be termed as the building block of the pavements without which all the pavement materials would behave independently and thus will be deemed useless.Almost ninety percent of bitumen is used in road construction. It is usually available in dark colors ranging from brown to black.CLASSIFICATION OF BITUMENCutback Bitumen: Cut-back bitumen are those which are prepared with the addition of a volatile to reduce the thickness of the binder.Fluxed Bitumen: Fluxed bitumen are those bitumen which are prepared by the addition of relatively non volatile oils to reduce the viscosity of the binder.Modified Bitumen: Modified bituminous binder are those whose properties such as cohesive strength, adhesive property, elasticity or viscosity have been modified by the use of one or combined chemical agents.Asphalt: Asphalt is a mixture of aggregates both fine (sand and filler) and coarse (stone) and a bituminous binder. It typically contains approximately 4-7% of bitumen. Asphalt is primarily used in road construction and its properties depend upon the type, size and amount of aggregate used in the mixture, all of which can be adjusted to provide the required properties for the desired application.

Properties of Bitumen materials1. Adhesive:Binds together all the components without bringing about any positive or negative changes in their properties.2. Water proof:Bitumen is insoluble in water and can serve as an effective sealant3. Strong:Though the coarse aggregates are the main load bearing component in a pavement, bitumen or asphalt also play a vital role in distributing the traffic loads to the layers beneath.4. Durable:Bitumen lives up to twenty years if maintained properly throughout the pavement life.5. Versatile:Bitumen is a relatively easy to use material because of its thermoplastic property. It can be spread easily along the underlying pavement layers as it liquefies when heated making the job easier and hardens in a solid mass when cooled.6. Economical:It is available in cheaper rates almost all over the world