1. Cement :
- It is prepared by heating lime (CaO), Clay (Al2O3.SiO2) and gypsum (CaSO4.2H2O)
- Functions of different constituents
a. Lime: it makes cement strong.
b. Clay : It provides strength and quick setting property to cement.
c. Gypsum : It regulates hardening time of cement.
- Cement contains (⅔)rd lime stone and (⅓)rd clay.
- When water is added to grinded mixture of lime and it is called slurry.
- Cement clinker is mixture of calcium aluminates and calcium silicates. It is hard grayish particle.
- A thick paste of cement and water is called mortar.
- Strength of cement is measured in its compressive strength which is expressed in mega pascal (MPa).
- Most commonly used cement is Ordinary portland cement (OPC).
- Cement is binding material in concrete.
- Clinker is formed around at 1500°C.
- Volume of 1 bag cement is 0.035 m³.
- In cement mortar 1 : 4 indicates the ratio of cement and sand.
- Normal bag of cement has weight of 50 kg.
2. Aggregate :
- Gravels crushed stone and other materials that are mixed with cement and water to make concrete is called aggregate.
- Durability and cleanness is essential requirements of aggregate.
a. Fine aggregate : Which passes through 5 mm B.S. sieve. e.g. natural sand.
b. Coarse aggregate : Which are completely retained on 4.75 mm sieve. e.g. crushed rock.
- Sand is fine aggregate.
- Initial increase in volume with increase in moisture content of sand is called bulking of sand.
- Bulking is more in finer sands than in coarser ones.
3. Concrete :
- Mixture of cement, sand, gravel and water is called concrete.
- W/C indicates water to cement ratio. Increase in W/C ratio decrease the strength and durability of hardened concrete.
- On increase A : B : C indicates ratio of cement, fine aggregate (sand) and coarse aggregate.
- Hydration is responsible for strength of cement particles.
- Water curing is done to reduce the heat generation during hydration in concrete.
- Comprehensive strength of concrete is determined after 28 days of curing.
- Concrete contain rod is called Reinforced Cement Concrete (RCC).
4. Building Stone :
- Generally rocks in the crust of earth are processed to give the building stones.
- The porosity of good building stone should be less than 5%.
- Classification of Rocks :
i. Geological Classification :
a. Igneous Rocks : Rocks formed by cooling and solidification of magma (hot viscous liquid within earth crust) are igneous rocks. e.g. granite, dolomite, basalt, etc.
b. Sedimentary Rocks : Rocks formed by deposition of existing rocks because of weathering action of water, wind, frost, etc. are sedimentary rocks. eg. gravel, sandstone, limestone, etc.
c. Metamorphic Rocks : When igneous rocks and sedimentary rocks undergoes into changes in their constitution is called metamorphic rocks. eg. gnesis, slates, etc.
ii. Physical Classification :
a. Stratified rocks : Rocks with layered structure in their natural form. eg. sandstone, limestone, slate, etc.
b. Unstratified rocks : They donot contain strata or layer in them. Eg. granite, marble, trap, etc.
iii. Chemical Classification :
a. Silicious Rocks : Rocks containing silica as their main component. Eg. sandstone, trap, granite.
b. Argillaceous Rocks : Rocks containing clay or alumina as their main components. Eg. slates, laterite, etc.
c. Calcareous Rocks : Rocks containing calcium carbonate as their main component. Eg. marble, limestone, etc.
5. Bricks:
- Bricks are clay products.
- They are derived by disintegration of igneous rocks.
- Al2O3.2H2O is commonly known as kaoline.
- Brick composition
i. Clay : 20-30% by weight.
ii. Silt : 20-35% by weight.
iii. Sand : 35-50% by weight.
- Red colour of brick is due to oxide of iron.
- Clay or Alumina makes brick hard.
- Silica or sand in brick prevents shrinkage and cracking of bricks.
- Pebbles of stones and Gravel, Alkaline salts, Limestone & kankar and vegetation and organic matter are harmful ingredients of brick.
- Standard size of common building bricks is 230mm × 110 mm × 55 mm.
- Strength of brick is measured in N/mm² or MPa.
- First class bricks has compressive strength not less than 10.5 MPa.
- Efflorescence is due to sulphates of sodium and potassium present in brick.
- The weight of common bricks was varies from 1600-1920 kg/m³.
- The number of bricks required per cubic meter of brick masonary is around 500.
- Clay is burnt at 1000-1200°C at kiln to prepare bricks.
- Black cotton soil is very good for making bricks.
6. Traffic Sign :
- It is prepared by heating lime (CaO), Clay (Al2O3.SiO2) and gypsum (CaSO4.2H2O)
- Functions of different constituents
a. Lime: it makes cement strong.
b. Clay : It provides strength and quick setting property to cement.
c. Gypsum : It regulates hardening time of cement.
- Cement contains (⅔)rd lime stone and (⅓)rd clay.
- When water is added to grinded mixture of lime and it is called slurry.
- Cement clinker is mixture of calcium aluminates and calcium silicates. It is hard grayish particle.
- A thick paste of cement and water is called mortar.
- Strength of cement is measured in its compressive strength which is expressed in mega pascal (MPa).
- Most commonly used cement is Ordinary portland cement (OPC).
- Cement is binding material in concrete.
- Clinker is formed around at 1500°C.
- Volume of 1 bag cement is 0.035 m³.
- In cement mortar 1 : 4 indicates the ratio of cement and sand.
- Normal bag of cement has weight of 50 kg.
2. Aggregate :
- Gravels crushed stone and other materials that are mixed with cement and water to make concrete is called aggregate.
- Durability and cleanness is essential requirements of aggregate.
a. Fine aggregate : Which passes through 5 mm B.S. sieve. e.g. natural sand.
b. Coarse aggregate : Which are completely retained on 4.75 mm sieve. e.g. crushed rock.
- Sand is fine aggregate.
- Initial increase in volume with increase in moisture content of sand is called bulking of sand.
- Bulking is more in finer sands than in coarser ones.
3. Concrete :
- Mixture of cement, sand, gravel and water is called concrete.
- W/C indicates water to cement ratio. Increase in W/C ratio decrease the strength and durability of hardened concrete.
- On increase A : B : C indicates ratio of cement, fine aggregate (sand) and coarse aggregate.
- Hydration is responsible for strength of cement particles.
- Water curing is done to reduce the heat generation during hydration in concrete.
- Comprehensive strength of concrete is determined after 28 days of curing.
- Concrete contain rod is called Reinforced Cement Concrete (RCC).
4. Building Stone :
- Generally rocks in the crust of earth are processed to give the building stones.
- The porosity of good building stone should be less than 5%.
- Classification of Rocks :
i. Geological Classification :
a. Igneous Rocks : Rocks formed by cooling and solidification of magma (hot viscous liquid within earth crust) are igneous rocks. e.g. granite, dolomite, basalt, etc.
b. Sedimentary Rocks : Rocks formed by deposition of existing rocks because of weathering action of water, wind, frost, etc. are sedimentary rocks. eg. gravel, sandstone, limestone, etc.
c. Metamorphic Rocks : When igneous rocks and sedimentary rocks undergoes into changes in their constitution is called metamorphic rocks. eg. gnesis, slates, etc.
ii. Physical Classification :
a. Stratified rocks : Rocks with layered structure in their natural form. eg. sandstone, limestone, slate, etc.
b. Unstratified rocks : They donot contain strata or layer in them. Eg. granite, marble, trap, etc.
iii. Chemical Classification :
a. Silicious Rocks : Rocks containing silica as their main component. Eg. sandstone, trap, granite.
b. Argillaceous Rocks : Rocks containing clay or alumina as their main components. Eg. slates, laterite, etc.
c. Calcareous Rocks : Rocks containing calcium carbonate as their main component. Eg. marble, limestone, etc.
5. Bricks:
- Bricks are clay products.
- They are derived by disintegration of igneous rocks.
- Al2O3.2H2O is commonly known as kaoline.
- Brick composition
i. Clay : 20-30% by weight.
ii. Silt : 20-35% by weight.
iii. Sand : 35-50% by weight.
- Red colour of brick is due to oxide of iron.
- Clay or Alumina makes brick hard.
- Silica or sand in brick prevents shrinkage and cracking of bricks.
- Pebbles of stones and Gravel, Alkaline salts, Limestone & kankar and vegetation and organic matter are harmful ingredients of brick.
- Standard size of common building bricks is 230mm × 110 mm × 55 mm.
- Strength of brick is measured in N/mm² or MPa.
- First class bricks has compressive strength not less than 10.5 MPa.
- Efflorescence is due to sulphates of sodium and potassium present in brick.
- The weight of common bricks was varies from 1600-1920 kg/m³.
- The number of bricks required per cubic meter of brick masonary is around 500.
- Clay is burnt at 1000-1200°C at kiln to prepare bricks.
- Black cotton soil is very good for making bricks.
6. Traffic Sign :
=> The main function of traffic sign is to regulate, warn and inform.
1. Red signal – To stop the traffic : Bring your vehicle to a complete halt behind the stop line or crass walk. Wait until the light turns green.
2. Amber/Yellow signal – caution : If you have entered the intersection and the light turns to amber/yellow, move on carefully. If you see the light before entering the crossing, stop the vehicle behind the stop line or cross walk.
3. Green signal – Go on : Go through the the crossing carefully. You can turn in the direction of the arrow by giving indicator.
• There are three groups of traffic signals.
i. Regulatory signs/Mandatory-order & Regulation sign :
- They are prohibitory (what drivers must not do) and mandatory (what drivers must do) types of signs.
- Most of them are in form of circular disc.
ii. Warning signs (Dangerous and warning signs):
- They warn drivers of some danger or difficulty on the road ahead.
- They are in form of an equivalateral triangle.
iii. Information signs :
- They give information to drivers to find their way to their destination.
- They are in form of either square or rectangular in shape.
iv. Pedestrian signals :
These signals help pedstrains to cross intersections safely.
• Steady Red human figure → Donot enter the road.
• Flashing signal → Cross the road quickly.
• Steady Green human figure → walk cautiously.
1. Red signal – To stop the traffic : Bring your vehicle to a complete halt behind the stop line or crass walk. Wait until the light turns green.
2. Amber/Yellow signal – caution : If you have entered the intersection and the light turns to amber/yellow, move on carefully. If you see the light before entering the crossing, stop the vehicle behind the stop line or cross walk.
3. Green signal – Go on : Go through the the crossing carefully. You can turn in the direction of the arrow by giving indicator.
• There are three groups of traffic signals.
i. Regulatory signs/Mandatory-order & Regulation sign :
- They are prohibitory (what drivers must not do) and mandatory (what drivers must do) types of signs.
- Most of them are in form of circular disc.
ii. Warning signs (Dangerous and warning signs):
- They warn drivers of some danger or difficulty on the road ahead.
- They are in form of an equivalateral triangle.
iii. Information signs :
- They give information to drivers to find their way to their destination.
- They are in form of either square or rectangular in shape.
iv. Pedestrian signals :
These signals help pedstrains to cross intersections safely.
• Steady Red human figure → Donot enter the road.
• Flashing signal → Cross the road quickly.
• Steady Green human figure → walk cautiously.
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