Building Materials

Stone

Toughness is the energy absorption per unit volume while Proof resilience is the max. strain energy stored per unit volume without permanent set.

Igneous rock has crystalline, glossy or fused structure. Igneous rocks are granite, basalt, traps dolerite, diorite, pegmatite,

gabbro, syenite etc. Sedimentary rocks are limestone, sandstone, shale, Tripoli, kankar,

chalk,dolomite, gypsum, diatomite, conglomerate, magnesite etc. Metamorphic rocks are quartzite, marble, gneiss, slate, schist,

serpentine etc. Moorum ( metamorphic, hard) shall be used in dressing of metal

road while pumice (igneous) shall be used in light weight aggregate.

Limestone and sand stone shall no be used together. Mineral in powder form is streak and its shiny appearance is

lusture. Stratified rocks (Sedimentary rocks) spilts along distinct layer

while foliated rocks (Metamorphic except marble & quartzite) splits in a certain direction.

Foliation rock is also known as S-tectonite. Bedding plane can be distinguished on the basis of variation in

color, composition & grain size. It is the plane of weakness. Foliation plane represents the band of different minerals in

metamorphic rock. Hardness can be measured by Sclerometer.

(talc,gypsum,calcite,fluorite,apatite,orthoclasefeldspar,quartz,topaz,corrundum,diamond)

Stone when broken other than a cleavage shoundn’t give dull appearances.

Quarrying shall be done by excavating, wedging, blasting and heating. Eg. Gun Powder, guncotton, cordite, dynamite. Blasting tools are steel jumper (1.8-3m,40mmdia.), tamping needle, scraping spoon etc.

Dynamite & Guncotton shall be exploded by detonation while Cordite & Gunpowder can be ignited by means of fuse. Gunpowder shall not be used to blast under water.

For using dynamite, dia. Of drills and bore hole depth are:0.6-1.8m - 25mm dia. 1.8-3.5m -40mm dia.3.5-5m -50-60mm dia.

In stone masonry stone shall be kept such that pressure acting on them is perpendicular to their natural bedding plane.

The minimum crushing strength of building stone should be 100kg/cm2.

Strength of stone in wet condition is 30-40% less . Granite has specific gravity of 2.64 and compressive strength of

70-130 MN/m2. It is mainly composed of quartz, mica and feldspar. Feldspar is responsible for color which may be grey, brown, green or pink. A fine grained granite offers resistance to weathering, easily polished, exterior facing work. Feldspar is silicate of aluminium with varying potash, soda or lime.

Slate has Sp. Gravity of 2.8 and comp. strength of 60-70MN/m2.Its color is grey or dark blue.Suitable in cisters, roof covering.

Gneiss is composed of quartz and feldspar. Street pavings Sandstone is composed of quartz, lime and silica with Sp. Gravity

of 2.65-2.95 and comp. strength of 35-40MN/m2. Its color is white, grey brown of pink. Shall be used in ashlar work, mouldings, carvings.

Limestone has Sp. Gravity of 2.6. Used largely in blast furnace. Color may be brown ,yellow and dark grey . Also used as stone masonry for walls.

Marble has Sp. Gravity of 2.7 used for ornamental and carvings. Kankar is impure limestone with 30% impurities of alumina and

silica. Shall be used in foundation of buildings. Laterite has Sp. Gravity of 2-2.2 with high % of iron oxide with

porous and cellular structure. Shall be used as building stone while nodular laterite is handy for road metal.

Moorum is decomposed laterite. Lighter color of stone are preferred to dark color. Closed grained and uniform texture stone are good in compressive

strength. Sp. Gravity of good stone should lie between 2.4-2.8. Quartz expands at low temp. while argillaceous stone resist high

temperature. Stone with good dressing property is weak in strength and

hardness. Stone shall be seasoned for 6-12 months before use. Piers, abutment, light houses- Good quality granite Road pavements and railway ballast- Inferior quality granite Road metallic pavement- Basalt and trap Cement concrete- Basalt and trap Ornamental work in bldg- Basalt and trap Damp proofing, roof covering, flooring and sills –Slate Partition of urinals and bath rooms- slate Ornamental bldg, monuments, carved work- marble Buidling construction- Laterite Interior decoration in superior buildings- serpentine

Brick

Bricks are ceramic materials. Sun dried bricks are weaker and not used where they are exposed

to rain.` 1st class brick shall have min. comp. strength of 10.5N/mm2 and

water absorption in 24 hrs shall be limited to 15-20% only. They can be used in facing work with no plastering ,outer walls, reinforced brick slabs, flooring with rich cement mortar.

2nd class brick shall have min. comp. strength of 7N/mm2 and water absorption in 24 hrs shall be limited to 20-22% only. They may have distorted round edge, and slightly overburnt with rough surface. Used for internal walls, facing work with plastering, not used in reinforced brick work, laid in lime or mud mortar.

3rd class brick shall absorb water upto 25% in 24 hrs. Slightly over/under burnt, soft ,easily broke, moderate efflorescence, no ringing sound, difficulty in uniform construction. Used for inferior construction, or the place with less rainfall or presence of dampness.

Jhamma or overburnt bricks are irregular in shape,dark in lumps, overburnt, hard and strong. Dark bluish color. Used in foundations, road materials and flooring.

Composition: Silica/sand=50-60%, Alumina=20-30%, Lime=10%, Alkali=<10%, Iron oxide=<7%, Magnesia=1%

Alumina in excess causes warp and crack in drying ,makes clay plastic.

Silica in excess causes brittle and weak otherwise retains shape, imparts durability and prevents shrinkage, warping.

Lime in excess causes brick to melt and loose shape, acts as flux prevents shrinkage and causes silica to melt.

Alkali ,clay with pyrite and water with gypsum may cause efflorescence otherwise alkali causes brick to melt and quick setting.

Iron oxide imparts color to brick. Exess may convert to dark blue, shouldn’t contain iron pyrite.

Magnesia softens clay and reduces warping. Excess effect color and make yellow.

Iron pyrite if present oxidizes,crystallizes and split the brick. Pebbles make non homogenous brick. Organic matter makes brick porous. Carbonacoeus matter makes brick black. Sulphur discolors the brick. No brick shall have comp. strength lesser than 55kg/cm2. Rough

test shall be done by dropping from1m height. Clay shall be unsoiled from 20 cm depth free from pebbles and

shall be exposed to open atmosphere for few weeks called weathering to gain plasticity. Clay shall be mixed with water and other ingredients called kneading/blending and shall be tempered in pug mills. It is observed that 1.5-2cum of soil produces 1000 bricks. Brick shall be hand moulded or machine moulded. Natural drying shall be done for 1 or 2 days in sun and then raised in hack for free air circulation. Artificial drying can be done if bricks are required in large no. during short period. Hand made bricks are superior for facing purpose.

Brick shall be burnt in clamp or klin. Kiln shall be intermittent or continous. Tunnel and hoffmanns are continous while bulls trench is intermittent. Brick shall be burnt in kiln for 24 hrs at temp of 1000-1200 C and shall be cooled for 12 days.

The average outturn of 1st class brick in clamp is 60 & while in kiln is 80-90&.

20 tonnes coal can burn 100000 bricks. Sp. Gravity of brick is about 2. Dimension test shall be done for 20 bricks. Water absoption test shall be done at 27+_2 C Compressive strength test: 5 sets of brick immersed in water for 24

hrs shall be filled with 1:3 cement sand mortar on frog stored under damp jute for 24 hrs followed by immersion in water for 3 days and then load of 14N/mm2 shall be applied.

Efflorescence test: Immersion of brick upto 1inch depth in water and let to evaporate. Process is continued for second time as well. If 10% deposites:Slight, 10-50% deposites: Moderate, >50% deposites: Heavy, Powder over exposed surface: Serious.

Overburning of bricks causes brick to loose their shape. Underburning of bricks causes high degree of water absorption and

less compressive strength. Bloating is the spongy swollen mass over bricks due to excess

carbonaceous matter and sulphur. Black core is the defect if brick clay contains bituminous matter or

carbon. Chuff is the deformation or crack on the surface of brick when rain

water drops on hot bricks. Cracks or checks are defects due to lumps of lime or excess of

water. Lamination is defect due to entrapped air in clay that forms thin

layer over brick surface making brick weak. Spots is the defect due to the presence of iron sulphide in the clay

that make brick appearance ugly in external face. NS standard brick shall be 224*108*57mm. Size of brick mould shall be slightly larger than that of brick. The metal plate to open or clos flue of kiln is damper.

Machine moulded bricks are stronger then hand moulded. No. of machine moulded bricks=530 and hand moulded=560 Refractory bricks are used in furnaces and chimneys to resist high

temp. and low coefficient of expansion and contraction. On external faces they serve to confine heat and prevents excessive loss to the atmosphere.Alumina content is increased in such bricks.

English bond: Stongest bond in which header and stretcher are placed in alternate courses. After first header, quoin closer shall be placed to stagger the vertical joint. Suitable for all wall thickness.

Stretcher bond requires less cutting of bricks and called half brick walls as well

Header is full brick wall. Flemish bond: Good looking appearance .Alternate header and

stretcher courses. Single Flemish bond consist of backing and filling of English

bond. Double Flemish bond consist of facing and backing of Flemish

bond and filling may be header or stretcher. Facing bond: If one header comes after several stretcher course.

Structurally not so good. English Garden wall bond: If a header comes after 3-5 stretchers

and and each header followed by quoin closer and middle course of stretcher with a header.

Flemish garden wall bond: If ¾ bat laid after quoin header in every alternate courses.

Raking bond: If the brick bonding are laid other than 0 or 90 degrees, called raking bond. Generally provided in stretcher course of wall. Types of raking bond:

Diagonal bond:Bricks laid diagonally, angle so selected that min. breaking of bricks is ensured.

Herringbone bond: Bricks are laid at an angle 45 from center in both the direction.

Zig zag bond: Similar to herring bond but laid in zigzag fashion. Dutch bond: Similar to English bond. It consist of 3 quarter bat in

quoin of stretcher course followed by header in each stretcher course.

Squint Brick: If the edges of brick wall are acute or obtuse. Round bricks: In circular pillar Perforated and hollow bricks: In partition or panel of multistoried

bldgs. Refractory bricks: Acidic brick (Fire bricks and silica bricks),

Basic bricks (Magnesite, dolomite and bauxite bricks), Neutral bricks (Chrome, chrome magnesite and spinel bricks)

Tiles

Thin ceramics slabs made by burning brick earth in kilns or by using concrete.

Brick earth used in tiles are purer then in brick. Pan tiles are similar to pot tiles but less curved and comparatively

heavier, stronger and durable than curved tiles. Terracota comprises of fine clay(60), powdered pottery(20), white

sand(14) and powdered glass(6), suitable alternative for stones on the ornamental parts of the buildings.

Tiles shall be used in flooring. Some of them are: Brick flooring: Godowns, stores, warehouses. Cement concrete :Common in residential, public and industrial

bldg. Granolithic flooring: If granite, basalt and quartzite is used as

coarse aggregate of 13mm down.

Terrazo flooring: Marble chips with white or coloured cement in the ratio of 1:2. Size of marble chips may be 3-6mm.

Timber flooring shall be provided in dancing halls and sanitoriums.

Rubber and cork flooring makes room noiseless and used in public offices, theatres, galleries, broadcasting stations etc.

Mosaic flooring: Broken tiles of china glazed or mable in different pattern. Pumice stone is used to rub.

Tiled flooring: Alternative to terrazzo flooring Marble flooring: where extra ordinary cleaning is required. Asphalt flooring: In swimming pools for non slippery action. Linoleum flooring: Rolls and laid directly on concrete or wooden

flooring., not recommended in bathroom, kitchens. The rolls are available in 2-4 m widths and 2-6mm thickness.

Glass flooring is done when lighting is to be transferred from upper floor to lower floor.

PVC flooring: widely used glued with concrete base. Flagstone flooring: laminated stone of rectangular or square shape

are laid over concrete bases.

Lime

It is obtained by heating limestone, kankar about 800. Used in plastering interior surface, preparing concrete for

foundation, timber, soil stabilization , white washing and flooring. Types of lime: Quick lime: Obtained by calcinations of pure limestone. Also

called white lime, fat lime, rich lime. It contains CaO content upto 95% and 5% impurity. It can set and hard only in the presence of C02 from atmosphere.Slakes upto 2-3 times. Long time to acquire strength. Used in whitewashing, plastering.

Slaked or Hydrated lime: Absorption of water by quick lime. Process of chemical combination of quick lime with water is slaking. Forms dry powder.

Hydraulic lime: The lime formed by chemical combination of silica, alumina and iron oxide with CaO( Kankar) is called hydraulic lime. It can set under water even in the absence of CO2.

Hydraulic lime on the basis of clayey impurities can be classified in 3 types: Feebly hydraulic lime:<10%, Moderately hydraulic lime:10-25%, Eminently hydraulic lime: 25-30%.

Feebly hydraulic lime: Slaking time:5-15min, Settting time:21 days

Moderately hydraulic lime: Slaking time:1-2 hrs, Setting time: 7 days

Eminently hydraulic lime: Slaking time:2-5 hrs, Setting time: 2-48 hrs.

Poor or lean lime contain more than 30% of impurities.So used for inferior type of work.

When quick lime is mixed with water, lumps are broken heat is generated and it swells in its volume giving fat lime.

Quick lime obtained form kiln is called lump lime. A thin pourable suspension of slaked lime in water is called milk

of lime. The process of adding water in quick lime to form calcium

hydroxide is called slaking. When the slaked lime is required in the form of paste or putty,

tank slaking is adopted otherwise platform slaking is done. Hydraulicity is the property due to which lime sets in damp

places. Lime putty: It is the thick creamy paste of hydrated lime in water.

Coarse stuff: If the sand is mixed with hydrated lime and mix water, such is called coarse stuff.

Milk lime: Thin pourable suspension of slaked lime in water. Ball test can be carried to know the expansion and disintegration

of lime ball after 6 hrs. Lime plaster: Lime:Sand 1st coat:1:2,2nd coat:2:1, 3rd coat:4:1

Cement

Calcerous and argillaceous stones are burnt in rotary kiln at a temperature of 1500 to form balls called clinker. The clinker is then cooled and ground to fine powder with some gypsum added, called Portland cement.

Constituent of cement are: Lime-63%, Silica-22%, Alumina-6%, Iron Oxide-3%, Magnesium oxide-2.5%, Sulphur trioxide-1.5%, Loss of ignition-1.5%, Alkalies-0.5%

Lime, silica and iron oxide impart strength, alumina gives setting ,alkali causes efflorescences and magnesium oxide & Suplur are undesirable in excess.

Lime makes cement strong and sound. Excess lime makes cement to expand and disintegrate.

Silica provides strength to cement due to the formation of dicalcium and tricalcium silicate.Excess may cause slow setting .

Alumina provides quick setting property and lowers clinker temperature.

Iron oxide provides strength , hardness and color. Also adds to the fusion of raw materials.

Magnesium oxide provides hardness and color to the cement. Excess makes cement unsound.

Sulphur trioxide in excess makes cement unsound. Alkalies in excess cause efflorescence.

Bogue compound forming clinker in cement are alite,belite,celite and felite.

Alite(45-65%) hydrates rapidly with huge heat of hydration,gives high early strength and less resistance to sulphate attack.

Belite(20-35%) hydrates slowly with less heat of hydration gives high ultimate strength and more resistance to sulphate attack.

Celite(5-15%) reacts with the water and generates huge heat of hydration,causes initial setting of cement.

Felite(8-18%) has poor cementing value,reacts slowly and generates less heat of hydration.

Higher the alite more better will be the cement. The setting and hardening of cement is mainly due to the hydration

and hydrolysis of these compounds. Gypsum shall be added 1-3%. Aluminate is responsible for max. heat and undesirable property in

concrete. So lesser the aluminate,low initial strength and high ultimate strength.

Mixing shall be done in ball mill, burning in rotary kiln and grinding in tube mill.

When 1gm of cement is heated at 900-1000, loss on ignition should not exceed 4% for good cement and insoluble residue should not be more than 1.5%.

Fineness test of cement shall be done by 2 methods: sieve and air permeability method .

In latter one, specific surface of OPC(2250cm2/gm),PPC(3000), LHPC(3200),RHPC(3250),SRPC(4000),Portland slag cement ( 2250).

The residue retained in No.9 IS sieve shall not exceed 10% by weight for OPC but 5% for RHPC.

The physical test shall be conducted at 25-29.

Consistency test to find the water content required to be added to cement is done in Vicat Apparatus. The penetration betn 33-35mm shall indicate normal consistency. It helps to determine IST & FST. Dia. Of mould is 100mm, plunger 10mm and height 40-50mm.

In order to make a cement paste of normal consistency, water shall be added 25-35%.

For IST test, water shall be added at the rate of 0.85P. For soundness test, water shall be added at the rate of 0.72P. For compressive test, water shall be added at the rate (P/4+3%). IST & FST of OPC and RHPC is same. Normal consistency of Portland cement is 25%. IST is the time in which crack that appear in the concrete do not

reunite. FST is the time in which concrete attains full strength and

hardness. Flash set is the property of cement in which upper surface

becomed hard without setting inner portion. Density of cement is 1440kg/m3. Gypsum shall be added at the time of grinding of cement. Soundness test shall be done by means of Le chatelier apparatus.

For OPC shouldn’t exceed 10mm. Compressive strength test: Standard cubes of 7.06cm are filled

with 1:3 cement sand mortar . Avg value of strength of 3 cubes for 3 and 7 days shall be 11.5 and 17.5 N/mm2.

Tensile strength test: Briquette test shall be done of 1:3 cement sand mortar. The avg. tensile strength shall be 2 and 2.5N/mm2 after 3 and 7 days. 6 briquette are tested

The rate of hydration and hydrolysis depends upon fineness of cement.

IST of LHPC is 60 min and Super sulphate cement is 4hr, QST is 5 min while other all same as 30 min. FST of super sulphate cement is 4hr 30 min and QST is 30 min, other all same as 10hr.

PPC contains 20-30% pozzolona materials. They are not cementitious material but react with calcium hydroxide in the presence of water to form cemetitious compound.

PPC need formwork for longer time but has high ultimate strength. Sp. Gravity of cement is 3.15. The chemical reaction between cement and water is called cement

hydration . The process in which plastic cement changes into solid mass is

called setting of cement. The process in which cement paste set and develop strength is

called hardening of cement. The tricalcium silicate hydrates more rapidly and develops strength

in cement in first 7 days. OPC has resistance to dry shrinkage and cracking but less

resistance to chemical attack. So not used for construction work exposed to sulphates in the soil.

RHC is lighter than OPC. Develops strength very early so that curing time is reduced and is economical. So used where high early strength is required such as road pavements, cold weather concreting. Not desired in massive concrete structures.

LHPC has less tricalcium silicate and more dicalcium silicate. Lesser compressive strength than of OPC,lesser lime content as well. Used for retaining walls but not for thin structures.

Sulphate resisting Portland cement consists of tricalcium aluminate content of 5% so that it becomes good sulphate resistant. Commonly used in canals, culvets.

High alumina cement:It contains 35% alumina. It sets quickly and develops ultimate strength at short period. So used in structure subjected to action of sea water, chemical plant and furnaces.

Blast furnace slag cement: OPC+granulated blast furnace slag. Develops low heat of hydration and less early strength. Used in dams,bridge abutments,and retaining walls.

Coloured cement: 5-15% of pigment added before grounding. Commercial name called colocrete. Finishing floors, walls

Pozzolona cement: pozzolona contains 80% of clay. Used in dams, weirs etc.

For good cement, it shall be greenish grey, cool when touched, floats when thrown in bucket and feels smooth when rub in fingers.

Mortar is the mixture of cement, sand and water or lime,sand and water or lime surkhi and water.

Sand and surkhi in mortar prevents shrinkage,cracks and gives strength .

The mortar used in concrete is called matrix. Mortar of coarse aggregate is stronger than that of fine aggregate. Concrete is the mixture of cement,sand, brick and water. Workability and durability of concrete depends upon quantity of

cement. Max. water content for durable concrete is 0.8. Shrinkage is directly propotional to cement content. Shrinkage of concrete is 0.3-0.6mm/m. Coefficient of linear expansion of concrete is almost same as that

of steel.

Steel

Ores for steel manufacture are: Magnesite:70-75%, Haematite:70%, Iron pyrite:47%, Siderite:40%

The crudest form of iron is pig iron and purest one is wrought iron.

Pig iron is obtained by removing impurities mixing iron with carbon and limestone.

Pig iron can be classified as Bessemer pig, Foundry/grey pig, Forge/white pig and mottled pig.

It contains of 3-4% of carbon and manufactured in blast furnace. Bessemer pig is obtained from haematite ore free form

sulphur,phosphorous and copper. Foundry pig is obtained from the furnace provided with fuel at

large temperature. Forge pig is obtained from the furnace provided without fuel at

low temperature. Mottled lies between foundry and forge. Cast iron is obtained by melting pig iron with limestone and coke

in cupola furnace. It contains 2-4.5% of carbon. Wrought iron is obtained by removing the impurities present in

the cast iron. It contains carbon less than 0.25%. In mild steel, carbon content is between 0.15-0.3%. In high cabon steel, 0.55-1.5% In high tension steel, <0.15%. As carbon content increases, steel becomes harder and tougher. Alloys are the ferrous and non ferrous alloys. Ferrous alloys are stainless steel, nickel steel, vanadium steel and

tungsten steel. Non ferrous alloys are brass, bronze, tin, lead, brazing solder,

german silver,duralumin Stainless steel:18% chromium, 8% nickel

Nickel steel: 0.5-1% carbon, 3.5% nickel Vanadium steel: 0.1-2% vanadium. Tungsten steel: 14-20% tungsten, 3-8% chromium. Brass:Cu (60-70%),Zn(60-40%) Bronze: Cu(90),Tn(10) Solder:Lead:Tin(1:2) Invar:Steel:Nickel(64:36) Monel metal:Cu:Nickel(60:40) German Silver:Cu:Zn:Ni Brazing solder:Cu:Zn:Tin:4:3:1 Duralumin:Al:Cu:Mg(94%:4%:2%)

Timber

Wood used for engineering purpose is called timber. When it forms the part of living tree , called standing timber. The main purpose of seasoning is to remove the moisture. By seasoning moisture shall be controlled to 10-12%. Other purposes of seasoning are making timber fire resistant,water

proof,light,strong and stable,prevent warping,shrinkage and cracking,resistant to decay by fungi and electricity.

Seasoning shall be done air and kiln. Former one is economical and slow while latter one is costly and quick.

Timber shall be made fire resistant by soaking it in ammonium phosphate,chloride,sulphate,sodium arsenate,boric acid etc.

Timber shall be applied to tree with not less than 0.6m in girth. Endogenous tree grows by the addition of new cells at top only so

that no lateral growth possible. Eg. Palm, bamboo, cane, coconut etc.

Exogenous tree grows laterally also. Eg. Deodar, kail, shisham,teak,walnut, oak etc.

Exogenous is further divided to soft and hard wood. Generally soft wood are conifers with pointed leaves. Eg.Deodar,

chir,kail,walnut. Hardwood are deciduous with broad leaves. Eg. Shisham, teak,

oak, Babul etc. Annual rings of soft wood are distinguished while less distinct in

hard wood. Medullary rays of hard one is distinct. Hard wood are darker. Soft wood are resinous. Heart and sap wood of soft wood cant be distinguished. Sawing of hard wood is difficult. Pith is the innermost central portion. Heartwood/duramen consist of inner annular rings between pith

and sapwood. Annular rings are concentric rings around pith. Sapwood consist of outer annular rings between heartwood and

cambium layer. Cambium layer lies between inner bark and sapwood yet to convert

into sapwood. Medullary rays are radial fibres extending from pith to cambium

layer. Bark/cortex Freshly felled tree contain moisture about 100-200% of its dry

weight. Air seasoning takes 60-90 days while 4-5 days in kiln seasoning. Defects of timber are: Heart shake: Due to overmaturity and shrinkage of heart wood. Star shake: Due to severe frost and severe heat of sun confined to

sapwood.

Cupshake or Ring shake:Due to wind that sway the tree or excessive frost which affect moisture present in tree when it is still young.

Knot:Defect due to roots of small brances of tree embedded in the stem with the formation of circular rings.

Foxiness: Due to overmaturity of tree and unventilated storage of wood.

Honeycombing: Imperfect seasoning of wood Dry rot: Due to fungus Wet rot: Alternate drying and wetting Rind galls: Curved swelling formed in the branches of tree due to

overgrowth. Checks: Cracks along longitudinal . Rupture/Upsets: injured fibers due to crushing. Some of the preservatives are: Charring is the process in which lower part of post upto15cm is

charred and quenched in water to prevent it from dry rots and worms.

Tarring Painting Creosoting: Creosote oil is dark brown thick liquid which is

applied in seasoned wood which is air dried for 24 hrs under pressure of 9kg/cm2 at 50 degree temp. It makes timber resistant against white ant and rots. Eg. Piles, transmission poles and railway sleepers.

Wolman salt: mixture of creosote oil and sodium fluoride which is extremey fire resistant and free from fungi attack.

Ascu also resist white ants. Sawing shall be done by four methods: Flat,Tangential,Radial and quarter sawing.

The most economical sawing is flat sawing. The process of removal of moisture under controlled condition at a

uniform rate is seasoning. Air seasoning gives strong wood than kiln seasoning. Air seasoning can reduce moisture content upto 18%. A board formed by gluing 3 or more usually odd numbers of

veneers is called plywood. In order to get more strength middle and face plies are used of different kinds of timbers.

3 ply-3-6mm,5 ply-6-9mm,7 ply-9-15mm, 9 ply-13-19mm Size of plywood varies fro 90*90 cm to 240*120 cm. It has uniform tensile strength in all directions. Temp. of 100-130 and pressure of 100-150 N/cm2. Grain are kept s.t one layer is perpendicular to other. Veneers are made up of teak wood and rose wood.

Ashphatltic materials

Bitumen is solid, semi solid black,sticky ductile substance obtained from the distillation of crude petroleum.

Bitumen is petroleum in fluid state, mineral tar in semi solid state and ashphalt in solid state.

Bitumen whose viscocity is reduced due to volatile solvents is called bitumen cutback. It is used in road construction and soil stabilization.

Bitumen suspended in finely divided condition in aqueous medium is called bitumen emulsion. It is used in soil stabilization.

Bitumen formed by blowing air throught it under high pressure and tempreture is called blow bitumen.

Bitumen distilled to definite viscocity of penetration without further treatment is called rut bitumen.

Viscocity & Ductility are inverserly related with temp. while softening point is directly related.

Asphalt are bitumen associated with inert mineral matter. They are formed by partial evaporation of petroleum oils.

Asphalt cutback:Prepre bituminous paints, roofing repair Mastic asphalt: Damp proofing and water proofing Asphaltic cement: water proofing and filler in expansion joint in

concrete. Asphalt comprises of 12% bitumen, 87% mineral and 1% organic

matter. Tar is the black solid mass obtained during the destructive

distillation of coal, wood or other organic agent. Tar can be categorized as coal,mineral and wood tar. Coal tar can be refined and distilled to get road tar. RT1 in extremely cold weather surface painting. RT2 in normal weather surface painting. RT3 in surface painting, renewal coats, premix top courses. RT4 in premix top macadam RT5 in grouting. Sheet asphalt is dense sand bitumen premix of compacted

thickness of 25mm used as a wearing course.

Paint

Oil paint is commonly used for engineering purposes. Bases used in paints are zinc white, red lead, white lead, titanium

white, lithophone, iron oxide. To hide the painted surface. Vehicle used are linseed oil, tung oil,latex emulsion, varnishes,

nut oil and poppy oil, acts as a binder for base and pigment. Pigment include carbon black, iron blue and chrome yellow. Maximum % of pigment in paint is 10%.

Thinner/ solvent are turpentine, naptha, petroleum,tolul, xylol, methylated naphthalene, spirit and alcohol added to the paint to modify the consistency of the paint and make its application smooth and easy.

Drier are red lead,litharge, lead acetate, manganese sulphate ,manganese dioxide,netheates, resonates and octates enables paint to dry quickly.

Drier shouldnt be more than 8% in weight. The inert filler powdered chalk, silica, gypsum,charcoal are used

to make paint economical ,reduce weight and durability and of desired quality.

Barium sulphate is widely used as adulterant because of its cheapness and property of not reacting with paint.

Types of paint: Oil paint: Ordinary paint, cheap and easy to apply, automobile Asbestos paint : Fire proof paint, applied on surfaces exposed to

acidic gases and steam Bronze paint: Radiator Cellulose: airplanes and other costly things,automobile also called

duco paint. Enamel paint: painting door and window frames and protecting

timber products. Emulsion paint: painting steel work and wood work built in

masonry. Cement paint: lasting finish on outer surface of wall. Defect of paint: Blistering: The swelling of paint film resulting in the loss of

adhesion between 2 coats due to the presence of moisture .If swelling is due to oil or grease called blistering ,if by moisture called peeling.

Checking: Formation of crack in the surface of paint. Crazing: Crack around small area Crocodiling/checking:If crack is around larger area. Cracking:If crack arises throughout the thickness of paint. Flaking: Detachment of paint film from surface. Aligatoring: When one paint slide over the other. Chalking: Paint converted into powder due to insufficient oil in

primer. Scaling: Improper seasoning of wood, excessive use of drier or

too many coats of paint results in cracks extending throughout the thickness of paint called scaling.

Bloom: Dull patches formed in the polished surface due to defect in paint of bad ventilation.

Crawling or sagging: Due to application of too thick paint. Fading: gradual loss of color of paint due to sunlight effect. Flashing:Formation of glossy patches in painted surface resulting

from bad workmanship. Grinning: Final coat not having sufficient opacity so that

background can be seen clearly. Running: Due to smooth surface, paint often runs back. Sponification:Formation of soap patches on painted surface due

to chemical action of alkali. Pigment volume concentration: It is the ratio of volume of

pigment to the total volume of non volatile constituents of the paint.

As PVC increases, gloss, washability ,adhesion and durablility of paint decreases.

Extenders are used to increase PVC without any change in other quality.So if pigment is costly and its covering power is high, a portion of pigment can be replaced by extenders without any

change in covering power of pigment. Eg. Gypsum,Talc,Silica etc.

Varnish is the homogenous mixture of resin, drier and solvent or thinner applied primarily in wood work. Its finish is generally glossy and is used in the paintings that are not to be framed in order to prevent entry of dirt or pollution from surrounding.

Resin are copal, amber, gum, lac or shellac and mastic Solvent is boiled linseed oil,methylated spirit or alcohol and

turpentine. Drier is litharge, white copper and lead acetate. Types of varnishes are: Oil varnish: External finish in houses. Turpentine varnish: Internal finish Spirit varnish: Formed by dissolving resin (shellac) in volatile

solvent (methanolated spirit). It is also called French polish. Used in furniture.

Water varnish: Internal work, covering of wall paper. Lacquer: Nitrocellulose, resin, solvents. Varnish are generally used in painted surface to increase

brilliance or to the unpainted wood surface to brighten the ornamental appearances of the grains of wood.

Distempers are also called water paint. It is made by mixing chalk with water as thinner with some colouring pigments and glue added.

It is extensively used as treatment of masonry walls and in plastered surface not exposed to weather.

Miscellanous materials

Plastics

They are organic material of high molecular weight which can be moulded to any shape subjected to heat and pressure in the presence of a catalyst.

They are natural or synthetic resins. Plastics are thermo plastic and thermo setting plastic. Thermoplastic are polyethene, polyvinyl chloride etc. Thermosetting are silicones, polyester, phenolics etc. Rubbers are also called elastomer. The unstretched rubber

molecular is amorphous. Rubber are made from latex obtained from sap of various plants. Rubber formed by coagulating rubber in retarder called sodium

bisulphite is called crepe rubber. Rubber formed by pouring latex in tanks having sides with

vertical grooves is called stroked rubber. Polymerization is the process of combination of 2 smaller

molecules of similar or different types with or without elimination of water forming new c-c linkage bond.

Depolymerization is the process of degradation of polymer by disrupting intermolecular bond within molecules of plastic formed under high temperature.

Addition polymerization is the reaction that yields a product with exact multiple of the original monomeric molecule. It contains one or more bond. Eg. Ethylene, polyethylene. Under application of heat, light, pressure.

Copolymerizatoin is the type of addition polymerization where simultaneous polymerization of 2 or more chemically different monomers takes place resulting in the formation of polymer containing monomers linked in one chain.eg.Butadiene + styrene=Styrene-butadiene polymer

Condensation polymerization is the reaction between monomers leader to the formation of polymer with elimination of some molecule of water, HCL etc. eg. Hexamethylene to nylon, Bakelite etc.

Thermoplastic are formed by addition polymerization and are soft on heating and hard on cooling.

Thermosetting undergo chemical change on remoulding so that they are chemically changed as well. They cant be reused any more. They are strong, brittle,hard and fairly string.

Constituent of plastics are: Resin act as an binder. Plasticizer neutralizes the intermolecular force of attraction

between resins. Fille increases hardness, strength, bond, opacity etc. Lubricant helps in easier moulding. Catalyst helps to accelerate polymerization. Blawing agent make porous product. Glasses are amorphous solid material, brittle and optically

transparent. Most commonly used glass is sodalime glass in windows and drinking vessels.

Silica is the fundamental unit of glass. Glass is formed by the fusion of silica, potash or soda at the

temperature of above 1000. It has been extensively used in building construction in glazing doors and windows.

There are glasses of 3 types: Soda lime glass, lead glass and borosilicate glass

Soda lime glass is used for glazing purpose and ordinary glassware.

Lead glass is used for electrical purpose and optical glasses. Also called flint glass.

Borosilicate glass withstands high temperature and used for making lab equipment and cooking utensils.

When one face of glass is made rough by grinding is called ground glass and used in bathrooms and kitchens.

When glass is reinforced with wire mesh is called wired glass and used for glazing north light trusses.

Lead or flint glases are brilliant due to increase refractive index and optical dispersion.

Barium also increases refractive index. Thorium gives high refractive index but less dispersion so it is

replaced by lanthanium oxide for high quality lens. Iron can be added to glass to absorb infrared rays. Lacquers are solution made of nitrocellulose, resins and

plasticizer in a solvent with or without pigments. Nitrocellulose imparts toughness and resistance to abrasion. Resins increase adhesion and hardness Plasticizer (castor oil) improve elasticity and plasticity. Solvent is the mixture of ketone, alcohol and hydrocarbon.

Soil Mechanics

Soil is non homogenous ,porous earthern mix of inorganic material formed by the disintegration and decomposition of rocks.

Soil mechanics is the application of hydraulics and mechanics to engineering problems related to sediments and other unconsolidated accumulation of solid particles.

Alluvial soil is transported from its place of disintegration by flowing water and deposited along the stream.

Marine soil is transported by water and deposited at the mouth of stream where it meets the sea.

Lacustrine soil are deposited at the bottom of lakes.

Loess or aoline soil is windblown yellowish dust particles consisting of silt and fine sand particles.

Dune sand is low hill of sand in sandy shores of sea, rivers and lakes.

Colluvial soil or talus are soil transported by gravitational force. Glacial drift are due to glaciers. Soil formed by decay of vegetables is called peat. The soil that remain in the parent rock is called residual soil. Classification of soil: Clay:<0.002mm,Silt:0.002mm-0.06mm;Sand:0.06mm-

4.75mm;Gravel:4.75mm-60mm;Pebbles:4.75-60mm;Cobbles:80-200mm;Boulder:>200mm

The capacity of soil to resist shearing stress is called cohesion. The phenomenon of strength gain and loss without any change in

volume and water content is called thixotropy. Loess is yellow coloured soil cohesive in nature. Hardpan is soil strata that becomes hard when gets wet. Bentonite is the volcanic ash that contains montmorillorite. Mooram is the mixture of iron, stone, gravel and red clay. Laterite are perforated and cellular in structure. Varved clay are alternate deposition of silt and clay. Loam is mix of sand and clay. Determination of grain size shall be done by sieve analysis or

sedimentation analysis. Former one is useful for coarse grained soil and latter one for fine grained soils by means of hydrometer and pipette.

Phase diagram represents components of soil. The diagram for fully saturated or fully dried is 2 phase while partially saturated is 3 phase diagram.

Fully compacted or consolidated soil are single phase system.

Void ratio is the ratio of volume of void and volume of solid. Porosity is the ration of volume of voil and total volume. Degree of saturation is the ration of volume of water to volume of

voids. For fully saturated,Sr=1 and perfectly dry,Sr=0 Water content is the ration of weight of water to that of solid where

weight of water means lost water when heated to about 105-110 degree for 24 hours.

Bulk or Mass unit weight is the ration of soil mass to total volume. Unit weight of solid is the ration of weight of soil solids to volume

of solids. Unit weight of water is the ratio of weight of water to its volume. Dry unit weight is the ration of weight of soil solid to volume of

soil mass. Submerged unit weight is the ration of weight of submerged mass

to total volume. Specific gravity is the ration of unit weight of soil to that of water

at 4 degree. Air content is the ratio of vol. of air to vol. of void. For formula refer books. Density index or relative density is the ration of difference between

void ratio in the loosest and densest state. Void ration shall be less equal or more than one. Porosity shall be less than one. For loose sand , compacted sand and silt clay porosity ranges 40-

50,30-40,20-30 % respectively. Adsorbed water: The film of water surrounding soil grain in the

film due to attractive forces between the particle and it. It has different density, freezing point than that of original water. It is also called hygroscopic or bound water.

Water outside the pore water which determine physical property of soil is called pore pressure.

Free water is water surrounding pore water that fills the void of soil mass.

Gravitational water is the water that enters the ground to form ground water.

Effective stress: pressure transmitted from grain to grain through point of contact. Also called intergranular stress.

Pore water pressure is pressure due to fluid present in pores. Also called neutral pressure.

Activity no. is the ratio of toughness index to percentage finer than 2 micron.If An<0.75,inactive:An=0.5-1.4,normal,An>1.4, active.

Sensitivity is the ration of compressive strength of undisturbed soil to that of disturbed soil.

Thixotropy means Sr>1. Relative density of 0-15,very loose:15-35, loose:35-65,medium:65-

85, dense:85-100,very dense. Properties of soil Water content shall be determined accurately by means of oven

drying method where,w=(m2-m3)/(m3-m1);m1=weight of container;m2=weight of container with wet soil;m3=weight of container with dry soil.

Sand bath method shall be used in field where the facility of oven drying is not available.

Calcium carbide method is the quickest method of determination of water content.eg. in embankment compaction

Pycnometer method is used to determine water content whose sp. Gravity is known. Suitable for CGS only.

Determination of specific gravity shall be done by 2 methods: density bottle method and pycnometer method.

Density bottle method shall be used in all types of soil and is accurate method while pycnometer shall be used only in CGS.

Determination of particle size distribution shall be done by 2 methods: sieve analysis and sedimentation analysis.

Sieve analysis is done for particle finer than 75 micron. Smallest sieve size in IS is 45 micron. The sieves are designated by

the size of aperture in mm. s.t 2 mm sieve means aperture size is square of 2mm.

Sedimentation analysis also called stokes law shall be applied for particles below 75 micron.

The size of particle from sedimentation analysis gives effective diameter. Upper and lower validity of stokes law is 0.2mm and 0.0002mm.

The hydrometer method is performed at temperature of 27 degree.Correction shall be done for temperature(+or-), meniscus(+) and dispersing agent(-).

The pipette method is used in laboratory as well in which certain dispersing agent is mixed. That is 7 gm sodium carbonate,33 gm sodium meta hexaphosphate and 1 litre distilled water.

For CGS, d10,d30 and d60 are important. D10 means 10% particles are finer than this size and also called effective diameter. The uniformity of coefficient, a measure of particle size range is the ration of d60 and d10. For uniformly grades soil, it is unity but for well graded soil,its value is more than 10.

Coefficient of curvature is ration of sq. of d30 divided by d60 and d10 product.

Cu for well graded gravel and well graded sand is >4 and >6. Cc for well graded gravel and well graded sand is 1-3.

Consistency of soil may be defined as degree of firmness of soil. Generally soil can pass through 4 stages:solid,semi solid, plastic and liquid state.

Liquid limit is the min. water content at which soil is still solid and just offers shear strength against flowing.

Plastic limit is the water content at which soil can be rolled into 3mm diameter thread.Shear strength is higher than of liquid limit.

Shrinkage limit is the max. water content of a saturated soil at which decrease in moisture doesnot affect the volume of soil mass. Water content beyond this limit gives solid.

Plasticity index is the difference of liquid limit and plastic limit. Shrinkage index is the difference of liquid limit and shrinkage

index. Relative consistency is the ratio of difference of liquid limit and

natural water content divided by plasticity index. Ic=0,liquid limit;Ic=1,plastic limit and >1 gives semi solid. Liquidity index is the ration of difference of natural water content

and plastic limit divided by plasticity index. Il=1,liquid limit;Il=0 plastic limit; Flow index is the variation in shear strength with water content. Ration of plasticity index to flow index is toughness index. Sensitivity of most of clay is 1-8 while that of normal clay is 2-4 The unconfined compressive strength of very soft clay is 10-

25Kn/m2 while that of hard clay is above 400Kn/m2. Soil structure can be described as: Single grained structure: arrangement composed of individual

particle. Eg. CGS Honeycombed structure: arrangement of particle with

comparatively loose, stable structure. Fine grained soils

Flocculent structure: Structure composed of flocs of particle instead of individual particle. Particles of soil are oriented edge to edge or edge to face. Fine grained soils

Dispersed structure: face to face orientation of soil. Fine grained soils.

Coarse grained skeleton structure: coarse grained skeleton partly filled with fine grained soils. Composite soils

Cohesive matrix: particle particle contact of coarse fraction not possible . composite soils

Permeability of soil is the property of soil mass which permits the seepage of water through its interconnecting voids.

As per darcy law, for saturated soil with laminar flow,discharge per unit time is propotional to hydraulic gradient.

Velocity of flow through total xsectional area under unit hydraulic gradient is called coefficient of permeability. m/s

Permeability shall be defined as constant head and falling head. Value of permeability depends upon direction of flow of water

through soil mass. Permeability of soil is directly propotional to square of avg. size

and inversely propotional to the viscocity. Quantity of seepage depends upon coefficient of permeability. Coefficient of permeability of silt is lesser than that of clay. Seepage pressure is the pressure exerted by water in soil thorugh

which it percolates. When flow occurs in upward direction, effective pressure

decreases . When seepage pressure equals submerged wt. of soil, effective pressure becomed zero, called quick sand condition. In this case, cohesionless soil loses all of its shear strength and soil have a tendency to move in up in direction of flow.

The hydraulic gradient at which quick sand condition occurs is critical hydraulic gradient. Ic=G-1/(1+e)

Ic value is generally equal to unity, increases with G and decreases with void ration.

Flow lines and equipotential lines intersect at 90 degree to each other.

The flow portion between 2 flow lines is flow channel while area enclosed between flow lines and equipotential lines is called field.

Exit gradient is the hydraulic gradient at downstream of dam. Also called tail water gradient or downstream gradient.

Max. permissible exit gradient is critical gradient divided by FOS. Dialatancy is the expansion of soil due to shear under constant

pressure. The total stress in soil are neutral or pore water pressure and

effective /intergranular pressure. Decrease in effective stress is accompanied by increase in neutral

stress. Effective stress is increased when water is flowing from upward

while neutral stress is decreased when water is flowing from downward.

Fine sands in saturated condition under sudden loading undergoes reduction in volume causes pore water pressure to develop causing decrese in effective pressure so that soil loses its shear strength and behaves likes liquid, called liquefaction.

Soil has zero tensile strength. Under compressive strength soil fails in shear. So shear strength is critical in case of soils.

Angle of internal friction of loose sand is 25-30 while that of dense sand is 32-37 degree.

As per couloumb law, shearing strength is cohesion plus normal stress *angle of internal friction.

Shear strength shall be determined by direct shear test, unconfined compression test, triaxial compression test, vane shear test.

Backfill above horizontal plane of top of retaining wall is called surcharge.

Lateral earth pressure exerted by soil when retaining wall has no movement relative to backfill, is called earth pressure at rest.

Lateral earth pressure exerted by soil when retaining wall moves away from the backfill is active.

While if retaining wall move towards the backfill is called passive earth pressure.

Value of active is minimal, and passive is maximum. Compressibility and consolidation: Compaction is the process of expulsion of air . Consolidation is the process of expulsion of water. For CGS with high permeability and low plasticity, 95% of

consolidation can be obtained under 1 minute time. Coefficient of compressibility is the ratio of decrease in void ratio

to the increase in pressure. Av=e0-e/dp As pressure increases, coefficient of compressibility decreases. Unit of coefficient of compressibility is inverse of pressure. Change in the volume per unit original volume due to increase in

pressure is called coefficient of volume change/volume compressibility. Mv=av/(1+e0)

Mv is directly propotional to av in inverse to e0. Coefficient of consolidation indicates combined effect of

permeability and compressibility of soil. Cv=k/(mv*yw) Degree of consolidation is the ration of settlement of fully

thickness of clay to the final settlement of clay when the process of consolidation is complete . denoted by U.

It is the function of time factor; tv=cv*t/d^2.

Coefficient of earth pressure is the ratio horizontal and vertical stresses. Ka=cot^2(45+phi/2)=1/(tan^2(45+phi/2))

Coefficient of earth pressure at rest,k0=u/(1-u) K0 for loose sand=0.4, hard clay=0.5, soft clay and dense sand=0.6

,sand compacted in layers and for stiff clay=0.8 Bearing capacity of soil: It depends upon grain size of soil, shape and size of footing. Ultimate bearing capacity: Min. gross pressure intensity at base of

foundation at which soil fails in shear. Net ultimate bearing capacity: Min. net pressure intensity at the

base of foundation at which soil fails in shear. Net safe bearing capacity: Net ultimate/ FOS Safe bearing capacity: Max. pressure soil can carry without failure

in shear. Allowable bearing capacity: Net loading intensity at which neither

soil fails in shear nor in excessive settlement.Objectives:

The rocks which are formed due to cooling of magma at considerable depth from earths surface is called plutonic rock while rock formed due to cooling at shallow depth from earth surface is called hypabyassal rock.

A good stone absorbs water not more than 5 % while stone is rejected if it absorbs water more than 10%.

The presence of sand in brick earth prevents cracking of bricks. The main ingredient of good quality earth brick is silica/ alumina . Clay and silt content in good brick earth must be at least 50%. The portion of brick without triangular portion equal to half the

width and half the length is called king closer. The lime which contains mainly calcium oxide and slack with

water is called quick lime.

The initial setting time of hydraulic lime is 120 minutes. Strength of concrete primarily depends upon water cement ratio. A piece of timber with thickness and width are 5cm and 10cm( or

less than) respectively is called strip. If both dimension less than 5cm, called batten. If thickness less than 5 cm and width greater than 10 cm, board. A short log 1.25m or less is called bolt. The timber having maximum resistance against white ant is

obtained from shisam/teak wood. The most commonly used solvent in oil paints is called petroleum. Turpentine oil is used in the paints as solvent/drier. Bituminous felts are used for covering AC sheets. Oil varnish consists of resin,oil and turpentine. The process of decarbonising the pig iron completely and adding

proper percentage of carbon for manufacturing steels is called cementation process.

Steel contain carbon approx. 0.01-1.5%. Lime stone comes under the category of aqueous, stratified and

sedimentary rock. The stone which exhibit highest compressive strength is gneiss. Sp gravity in descending order is lead, tin, zinc and aluminium. In heat treatment of steel, steel is heated to red hot and then dipped

in cold water is called hardening. The process involved in the manufacte of wrought iron from pig

iron are refining, pudding and rolling. Marble contains lime and silica. The max. percentage of fine sand, silt and clay in making good

tiles are 40,30,30. Sand is mixed with lime mortar to improve strength. Advantage of adding pozzolona to lime is to impart strength.

Fat limes are used in distempers. As compared to fat lime, hydraulic lime sets very slowly. Gypsum is added to cement before burning. While preparing lime mortar, inert material used is brick powder. Portland cement is formed by burning in a kiln, limestone and clay. Workability of concrete is most influenced by its water content. Cement paints minimizes seepage. Enamel paint consist fo white lead or zinc white, petroleum spirit

and varnish. Polish dries quickly out of paint, varnish and enamel. Color of ashphalt is black brownish. For window or glass panes of 60 x60 cm opening, thickness of

sheet glass is 2.5mm. In air conditioned office, glass used is foam glass. Mica has least affinity for moisture among copper, paper and

asbestos. Plywood are preferred to planks due to good strength and

dimensional stability in both directions. Quick sand condition is the case in which cohesionless soil loses

its strength due to upward movement of water in soil. The height of capillary rise is maximum in case of colloids. The capillary rise of water depends upon the force responsible. The angle of internal friction of clay is 5-20 degree. The compression resulting from long term static load and

consequent escape of consolidation. The shearing strength of cohesionless soil depends upon the

confining pressure and normal stress. The property of soil of great importance in final settlement of

strucuture is called consolidation.

Coarse grained soil contains materials half of which is larger than 75 micron.

Liquid and plastic limit exists in clay. The earth pressure in the retaining wall depends upon the angle of

internal friction of soil. Total lateral earth pressure is propotional to the square of depth. The most suitable method for increasing the bearing capacity of

black cotton soil is replacing black cotton soil by sand. As void ration increases, it is more pervious. The consolidation settlement is directly propotional to the

compression index. The range of optimum water content for the standard proctor test

for clayey soil is 14-20%. 80/100 in bitumen is penetration grade. Sand, silt and clay nearly in equal proportion is called loam. The good clay for making bricks is weatherd clay. The process at which steel is passed through a small hole to make

cylindrical rods and wires is called drawing. The size of machine made bricks in Nepal is 240*120*60mm. Stone that exhibits least crushing strength is sandstone. Spalling hammer is used for rough dressing of stones. Tool used for quarrying stones is jumper out of priming

needle,dipper and spalling hammer. The soil good for making bricks is clay soil out of alluvial, silt and

sand & silt. The temperature at which bricks are burnt varies from( low melting

clay) is 700-1000 degree. Fire bricks should be laid in a fire clay mortar. In case of clamp burning, brick shall be laid at 15 degree. The main component of lime responsible for hydraulicity is clay.

As compared to fat lime, hydraulic lime set faster. Constituent responsible for setting of hydraulic lime under water is

silica. The calcinations of pure lime gives quick lime. Dormant period is related to hydration of cement. Steel used for manufacture of rails is Bessemer steel. Defect of wood due to hardening is called burls. Time require for seasoning of timber in air is about 4-6 months. Timer with width dimension excedd 5cm in one direction and 20

cm in other is called bauk. Vehicle used in case of enamel paint is linseed oil. Commonly used thinner in oil paint is naptha or turpentine. Behavour of silt is governed by mass and surface energy. Concreting shall be stopped if temperature fall below 15 degree. A limestone found in seams of great thickness in non crystalline

texture with earthy appearance is called compact limestone. The compressive strength of sandstone is 65MN/m2. The railway ballast stone shalle be hard, tough,dense, durable and

easily workable. Quarrying of stone by wedging is successfully carried out in

marble, sandstone and limestone. The compressive strength of perforated brick is not less than

7MN/m2. Compressive strength of paving brick not less than 40MN/m2. The length of curved tile varies from 15-20 cm. Fuel used for burning limestone is coal,charcoal and firewood. During the burning of limestone, clay form certain compound

which give hydraulic lime,give power of quick setting, doesnot allow to be dissolved in the outside water when used in damp condition.

Quick lime on reaction with water gives slaked lime,not hydrated lime.

Constituent in lime retarding slaking action and increasing rapidity of setting is silica.

The dry process of mixing is usually employed in the manufacture of Portland cement when the raw material is blast furnace slag.

Gypsum is added in the manufacture of Portland cement at the end of grinding the clinker into powder.

Cementing property of lime is mainly due to lime. Percentage of slag component of Portland slag cement varies from

40-70%. Rapid hardening cement has high heat of hydration and high

shrinkage coefficient. Sand is added to lime mortar to reduce shrinkage and cracking. Consolidation of concrete should proceed immediately after

placing. Workability of concrete shall be improved by adding quantity of

cement. Moisture content in timber for framework shall not exceed 15%. Thickness of lamin boards is 12-25mm. Wood used in railway sleepers is kail. Chief ingredient of paint among drier, oil and pigment is pigment. Liquid medium in oil paints is turpentine/ linseed oil. Vehicle used in bronze paint is nitrocellulose laquer. Spirit varnish consists of spirit and shellac. Stucco paints consist polyvinyl acetate. Engineer is mainly concerned with top 10-15 m soil for medium

sized project. Black cotton soil are inorganic soil with high percentage of clay

content,exhibits compressibility and is an inorganic soil.

Compressibility and consolidation deals with change in the volume of pores in a soil under load.

Unit weight of soil at zero air void depends upon water content, sp. Gravity, and unit wt. of water.

Degree of saturaton of moist soil is 50-75%. For clay particle force of gravity on each particle is negligible as

comapared to electric surface charges. Sp. Gravity of sandy soil is 2.7 Density of saturated>wet>dry>submerged. As per stoke law, velocity at which grains settle out of suspension,

all other factors being equal is depended upon weight, shape and size of grain.

Soil of nearly same size is called uniform soil not well graded soil. Unconfined compressive strength of soft clay is 10-25 and that of

hard clay is >400. Sensitivity of normal clay is 2-4 while that of most clays is 1-8. Water content reduced beyond shrinkage limit gives solid. Plastic and liquid limit exists in clay. Clay containing high activity contains montmorillonite and high

plasticity index. Gravel is practically impermeable. Sample of clay and sand having same void ration and specific

gravity, their permeability differ due to different size range of their void.

If direction of flow of water is parallel to the planes of stratification, permeability is 2-30 times more than in plane perpendicular.

Permeability of soil is directly propotional to square of grain size. Flow net is used to determine seepage flow, pressure and exit

gradient.

Seepage pressure is independent of coefficient of permeability. Permissible exit gradient for safety against piping which endanger

the stability of hydraulic structure should be 0.2 Effective stress is due to weight of soil particles and external load

acting on soil. Time factor for clay layer is directly propotional to permeability. Compression index of soil increases with the increase in liquid

limit. Ultimate settlement of soil is propotional to compression index,

increases with decrease in void ratio, and depth of compressible soil mass.

Strength of soil is identified by ultimate shear stress. Shear stress on dense sand causes the volume to increase. Density index is used to determine the angle of internal friction of

sandy soil. Frictional resistance of clay soil is less than that of sandy soil. Frictional resistance of sand is sliding, rolling or due to

interlocking. Useful method for finding shear strength of very plastic cohesive

soils is vane shear test. Line showing dry density as a function of water content of soil

containing no air voids is called saturation line. Effect of cohesion of soil is to reduce active and increase passive

earth pressure. Earth pressure at rest is calculated by using theory of elasticity. Lateral earth pressure is propotional to the square of the depth of

soil. Unit bearing capacity of footing in sand increases with depth and

width of footing.

As per IS code, total settlement of isolated footing for cohesive soil shall be 65mm.

In footing design in sand, general shear failure are used for angle of friction 36 degree.

When water table is close to ground surface, bearing capacity of soil reduces to half.

When water table is below footing at depth equal to half of width of footing, bearing capacity reduces to threefourth.

If the dry or moist soil is present below footing,then confining pressure shall be double of the case water is upto base of footing.

Incase of sand footing ,max soil pressure is double if load distribution is triangular.

Settlement of flexible footing in cohesionless soil is more at edges than at center while uniform throughout for rigid footing.

For cohesive soils , settlement of flexible footing is more at center. Contact pressure of flexible footing in cohesionless soil is more in

center than at edges. Contact pressure of rigid footing on cohesive soils is less at center

than at edges. High density of fill is ensured to increase shear resistance,reduce

settlement and percolation. Critical height for soil is max. height at which sloped bank of soil

is stable. Inorder to protect beam from corrosion, min. cover of 100mm shall

be provided on outer surface. In made up ground having low bearing power, heavy concentrated

structural loads are generally supported by raft foundation other than combined or strap footing.

Coefficient of friction between concrete and soil is 0.3-0.35 Water jet pressure for driving pile is 0.7-1.75N/mm2.

c/c distance of reinf. In precast concrete piles shall not exceed half the least width of pile.

Quality of concrete recommended for precast concrete piles is M150-M200 and thickness covering main bars shall be 40mm.

Cover for reinf. In sea water is 55 mm. For depth 4-6m, cofferdam reqd. is single walled cofferdam. Water tight structure for excavation of foundation for bridges is

caisson. For stability, lowermost course of wall footing shall be twice of

wall width. Mostly used material for damp proofing is bitumen. In case of building without basement, best position of DPC lies at

plinth level. Commonly adopted material for DPC at plinth level is cement

concrete. Semi rigid material forming excellent impervious layer is mastic

asphalt. Bituminous sheeting are flexible one to be used in DPC. Nogging pieces are housed at a vertical distance of 600-900mm. Width of jamb is 76-114mm while depth is 56-76mm. Louvered doors maintain free ventilation and privacy as well. Slump for concrete in road works is 20-28mm while in column is

75-175mm. Commonly used pointing in BW and SW is flush pointing in which

joitns raked are first filled and finished off flush with edges of bricks/stones.

While in tuck pointing finished off flush with face of bricks/stones. Process of filling nail holes,cracks with putty is stopping. Single grained strucuture are CGS, silts are honecombed, clays are

flocculent and clay remoulded are dispersed.

Void ration may go between 0.5 and 1.5 Soil refers to a particulate medium. Water content of soil may be greater than100%. Density index refers relative compactness. Soil sample for hydrometer anlaysis is pretreated with oxidizing

agent. Peroxide in hydrometer is to remove organic matter. Asbestos content in asbestos cement sheets is roughly about 15%. Dolomite contains carbonate of magnesia upto 45%. Slaking is affected by affecting lime in water. IST of hydraulic lime is 120 minutes while that of lime-pozzolona

is 90 minutes. Curing period of lime mortar is 7 days. Slump for lime is 50-75mm. Flexural strength is 0.2N/mm2. Compressive strength in 90 and 26 days are 1.5&1.2 N/mm2.