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BUILDING MATERIAL

&CONSTRUCTION-

 Gypsum is a mechanically formed sedimentary

rock.

 Quartzite is a silicious rock.

 Slate is formed by metamorphic action on shale.

 Heavy stone is suitable for retaining wall.

 Hard stone is suitable for rubble masonry.

 Soft stones is suitable for ornamental work.

 Quartzite has most weather resisting

characteristics.

 A good building stone should not absorb water

more than 5%.

 Compact sand stone has more fire resisting

characteristics.

 Weight test is conducted on a stone used in

docks and harbours.

 Granite stone is best suited for construction of

piers and abutments.

 Crushing strength of good building stone

should be more than 100mpa.

 Specific gravity of most of the building stone

lies between 2.5 to 3.

 Pith-annular rings-heartwood-sapwood-

cambium layer-inner and outer bark.

 Shisham is hard wood and offer maximum

resistance to the white ants.

 Star shakes-the radial splits which are wider on

the outside of the log and narrow towards the

pith.

 Chir and deodar yields soft wood.

 Mulberry tree used for making of sports goods.

 Dry rot caused due to lack of ventilation.

 Foxiness caused due to over maturity.

 Honey combing caused due to-seasoning.

 Strength of the timber is maximum in the

parallel direction.

 10% to 12% is the moisture content of well

seasoned timber.

 The age of the tree can be known by annular

rings.

 1st class timber has an average life of more than

10 years.

 1st class brick should not absorb water more

than 20% when immersed in water for about 24

hours, 22% for 2nd class bricks and 25% for 3rd

class bricks.

 Crushing strength of 1st class bricks not less

than 10.5N/mm^2, 7.5N/mm^2 for 2nd class

bricks.

 The main function of alumina in brick earth is

to impart plasticity.

 The percentage of alumina in good brick earth

is 20 to 30%.

 Excess of alumina in brick earth cause crack

and warp on drying.

 Excess of silica cause brittleness.

 20*10*10 cm is the nominal size of the brick.

 19*9*9cm is the standard size of brick.

 50 to 60 % silica in good brick earth.

 Silica makes the brick to retain the shape.

 Kneading –the process of mixing the clay water

and other ingredients called.

 60 to 70% turn over in clamp burning where as

80 to 90% turn over in kiln burning.

 Pug mill used for preparation of clay.

 Refractory bricks used in combustion

chambers.

 The frog of the brick generally kept on the top

face of masonry.

 500 bricks required for one cubic metre of brick

masonry.

 Quick lime is calcium oxide.

 Hydraulic lime is obtained from burning of

kankar.

 Lime and silica are the main ingredients of the

Portland cement.

 C3A is responsible for all undesirable

properties of cement.

 Le chate lier apparatus is used for testing the

soundness of cement.

 Vicat apparatus used for testing setting time of

cement.

 C3A is responsible for intial setting time of

cement.

 The intial setting time for ordinary Portland

cement not less than 30minute.

 The final setting time should be 10 hour.

 The normal consistency of ordinary Portland

cement is 30%.

 Early attainment of strength of cement in

rapid hardening of cement is due to finer

grinding.

 After storage the strength of the cement is

decreases.

 Addition of pozzolana to ordinary Portland

cement cause shrinkage.

 Gypsum consists of caso4 and H2O.

 25mm to 50mm is the slump recommended for

mass concrete.

 Low heat cement is used in massive concrete

structures.

 Calcium chloride is the common admixture to

accelerate the intial setting time.

 The basic purpose of retarder in concrete is to

increase the intial setting time of concrete.

 Gypsum is most commonly used retarder.

 Carbon influences the maximum properties in

steel.

 Wrought iron is the purest form of iron.

 The ultimate tensile strength of steel is

420N/mm^2.

 0.25% of carbon in mild steel.

 Yield stress is used for identifying the quality of

structural steel.

 Flemish bond –alternate courses of header and

stretcher.

 English bond-alternate header and stretcher.

 The pressure acting on the stones in stone

masonry should be perpendicular to the direction

of bedding planes.

 Queen closer-the brick is cut into 2 equal parts

in length wise.

 English bond is provided in masonry for

carrying heavy loads.

 Slenderness ratio-effective length to least

radius of gyration, for masonry walls not more

than 20.

 The differential settlement in case of sandy soil

not more than 25mm.

 In case of foundation on black cotton soil the

most suitable method is to replace the poor soil.

 Grillage foundation is the most economical

foundation to transmit the heavy load.

 Batter pile is used to resist the horizontal and

vertical forces.

 0.9m is the minimum depth of the foundation on

clay soil.

 The bearing capacity of a water logged soil can

be improved by draining the soil.

 Depth or height of arch-is the perpendicular

distance between the intrados and extrados.

 Flat roof is constructed where the rainfall is less

and temperature is high.

 Pitched and sloping roofs are suitable for

coastal region.

 The maximum number of steps generally

restricted is 12.

 Sum of tread and rise must between 400 to

450mm.

 Minimum width of landing should be equal to

width of stairs.

 In any good stair case the maximum and

minimum pitch is 40’ and 25’.

 Doglegged stairs are half turn stairs.

 Horizontal projection at head and sill called

horns.

 Revolving door is suitable for entrance in an air

conditioned building.

 Attrition test determines the rate of wear of

stones.

 Efflorescence-formation of white patches on the

brick surface due to presence of alkalies.

 Vanadium steel used in the manufacture of

axles and springs.

 Neoprene is suitable for bearing of bridges.

 To produce low heat cement it is necessary to

reduce the C3A.

 Timber can be made more fire resistant by sir

abel’s process.

 Creosote is derived from wood or coal.

 Excess of sulphur in steel results in red

shortness.

 Distemper is used to coat interior surface not

exposed to weather.

 Putty is made up of powdered chalk and raw

linseed oil.

 The limit of proportionality is applied more in

the case of mild steel.

 The compacting factor test determines the

workability.

 The split tensile strength is 10% to 15%.

 The approximate ratio between the strength of

cement concrete 7 to that of 28 days is 2/3.

 The moisture content of timber is 12%.

 0.85P times amount of water is used ofr intial

setting time, 0.72P for soundness cement.

 Lime mortar is generally made with hydraulic

lime.

 The texture of sand stone is granular

crystalline.

 Seasoning of timber is required to remove sap

from timber.

 The ratio of youngs modulus of high tensile

steel to that of mild steel is about 1.

 Poly vinyl chloride is thermoplastic material.

 King closer is related to brick masonry.

 High alumina cement is produced by limestone

and bauxite.

 The optimum number of revolutions required

for concrete mix is 20.

 Manganese steel used in the manufacture of

rails.

 Gauged mortar is obtained by adding sand and

lime.

 1300’to 1500’ is the temperature range of

cement in kiln.

 Before testing setting time of cement one

should be test for consistency.

 The super plasticizer in a cement paste is

disperse the particles, remove air bubbles and to

retard setting.

 Surkhi is added to lime mortar to impart

hydraulicity.

 Increase in fineness of cement results in

increase in development of strength and leads to

higher shrinkage.

 The purpose of frog is to form key joint

between brick and mortar.

 Bricks are burnt at a temperature of 900-1200

degree Celsius.