Stone –Stones can be obtained from Various Rocks.
Rocks classification.
Geological
Chemical
Physical
>>Geological classification of rocks
1.Igneous rocks – These are formed By cooling of magma.
These rocks further classified as
2. Sedimentary Rocks - Disintegrated rocks Material, can be carried by transportation and deposited anywhere.Examples- Sand stones, Mud stones, Limestone.
3. Metamorphic Rocks – These are formed due to alteration of, original structure due to heat and excessive pressure. These rocks are foliated structures. Examples-
Granite become Gneiss,
Basalt to schist and laterite,
Limestones changes to marble,
Mudstones changes to slate.
>>Chemical classification of rocks.
>>Physical Classification of rocks
1) Stratified Rocks –
These types of rocks possess plane of stratification & they can easily be split up along these planes.
Eg. Sedimentary rocks
2) Un-stratified Rocks –
These types of rocks does not possess plane of stratification & they crystalline granular or compact granular.
Eg. Ingenious rocks
3) Foliated Rocks –
These types of rocks have a tendency to split up in definite direction only&having foliated structure.
Eg.Metamorphic rocks
Requirements of good building stone:-
1) Crushing – A good building stone should have better crushing strength i.e. greater than 100 N/mm2
2) Hardness - A good building stone should have sufficient hardness.
3) Durability - A good building stones must be durable long lasting nature.
4) Fire resistance - They should have good fire resistance properties.
5) Seasoning/weathering - They also have good weathering resistance properties.
6) Water resistance - They should have less water absorption properties.
7) Economy - They should be economical & easily available.
8) Attrition – A good building stone should have less wear & tear, abrasion & erosion properties.
9) Facing & dressing – A good building stones should be easily molded, craved & dressed.
10) Specific gravity - A good building stone should have higher specific gravity i.e. more than 2.7.
11) Texture – The structure of the good building stone should be compact fine crystalline. They don’t have any cracks, cavities & patches.
12) Toughness - A good building stone should have strong&tough.
Characteristics of stone:-
1) Appearance – Stones should have fine, compact texture & uniform colour.
2) Structure – the structure of stones should be uniform without cracks, fractures, cavities etc.
3) Strength - stone should have better crushing strength i.e. greater than 100 N/mm2
4) Weight – The weight of stones should be considerable & suitable for various construction sites.
Eg. For dam & retaining walls – heavy stones are used
For domes, arches – light stones are used
5) Hardness - stones should have sufficient hardness
6) Toughness - stone should have strong&tough
7) Specific gravity - stone should have higher specific gravity i.e. in between 2.3 to 2.5.
8) Seasoning – stones should be well seasoned
9) Work-ability – Stones should be workable for cutting, dressing with required shapes.
10) Chemical resistance – Stones should resist alkalies, acids, corrosive gases etc
11) Durability - stones should be durable long lasting nature
12) Water resistance - stones should have less water absorption properties
Quarrying and dressing of stone
Quarrying of stones: The method of removal of stones from their natural bed by using different operations is called quarrying.
Methods of Quarrying –
a) Digging – This method is used when the quarry consists of small & soft pieces of stones.
b) Heating – This method is used when the natural rock bed is horizontal & small in thickness.
c) Wedging –This method is used when the hard rock consists of natural fissure. When natural fissures are absent then artificial fissures are prepared by drilling holes.
Wedging required tools –
i) Steel wedge
ii) Conical steel pin or plug
iii) Flat steel wedge
iv) Wooden plug
v) Pneumatic drill
d) Blasting – It is the process of removal of stones with the help of controlled explosives is filled in the holes of the stones. Line of least resistance plays very important role in the blasting process.
Following steps are used in the blasting process:
1) Drilling holes – Blast holes are drilled by using drilling machines.
2) Charging – Explosive powders are fed into the cleaned & dried blast holes.
3) Tamping – The remaining portion of the blast holes are filled by clay, ash, fuse & wirings.
4) Firing –The fuses of blasting holes are fired by using electrical power supply or match sticks.
Dressing of stones:-
1) Rough dressing quarry - It is the process of stone dressing which gives the broken stones in to the suitable pieces the shapes & sizes.
2) Pitched face dressing - It is the process of stone dressing which gives the same plane & square of the surface
3) Hammer dressing - It is the process of stone dressing which gives the sharp less irregular corners of the surface distance by using hammer. It is suitable for mensory work.
4) Rock face dressing - It is the process of stone dressing which gives the four edges having 2.5 cm surface distance by using chisels.
5) Rough tooling - It is the process of stone dressing which gives more or less paralle , hori onta , vertica at ang e of the surface.
6) Punched dressing - It is the process of stone dressing which gives the parallel ridges with required gaps between the surfaces.
7) Fine tooling – It is the process of stone dressing which gives the fine &smooth surface of the stones
Stone dressing tools:-
1) Mason’s hammer
2) Spacing hammer
3) Scabbing hammer
4) Club hammer
5) Soft stone chisel
6) Claw chisel
7) Punching chisel
8) Point chisel
9) Drafting chisel
10) Pitching tool
Seasoning and preservation of stones-The process of removing the sap.
Dry the stones for a period of 6 to 12 months in a shed.The following preservatives are used.
Linsed oil, Solution of alum and soap, Solution of barium hydroxide, Coal tar, paint and Paraffin.
Test on stones – Field tests
Test on stones – Laboratory tests.
Rocks classification.
Geological
Chemical
Physical
>>Geological classification of rocks
1.Igneous rocks – These are formed By cooling of magma.
These rocks further classified as
- Volcanic rocks – Cooling of magma at earth surface, examples-Basalt and Trap.
- Hypahyssal rocks – cooling of magma at shallow depth, examples-quartz, dole rite and Gneiss.
- Plutonic rocks – cooling of magma At considerable depth, examples-Granite and Dolomite.
2. Sedimentary Rocks - Disintegrated rocks Material, can be carried by transportation and deposited anywhere.Examples- Sand stones, Mud stones, Limestone.
3. Metamorphic Rocks – These are formed due to alteration of, original structure due to heat and excessive pressure. These rocks are foliated structures. Examples-
Granite become Gneiss,
Basalt to schist and laterite,
Limestones changes to marble,
Mudstones changes to slate.
>>Chemical classification of rocks.
- Siliceous Rocks- main constituent is silica, examples, Granite, Trap and sandstones.
- Argillaceous Rocks- main constituent is clay, examples, Slate and laterite.
- Calcareous Rocks- main constituent is calcium, examples Limestone and marbles.
>>Physical Classification of rocks
1) Stratified Rocks –
These types of rocks possess plane of stratification & they can easily be split up along these planes.
Eg. Sedimentary rocks
2) Un-stratified Rocks –
These types of rocks does not possess plane of stratification & they crystalline granular or compact granular.
Eg. Ingenious rocks
3) Foliated Rocks –
These types of rocks have a tendency to split up in definite direction only&having foliated structure.
Eg.Metamorphic rocks
Requirements of good building stone:-
1) Crushing – A good building stone should have better crushing strength i.e. greater than 100 N/mm2
2) Hardness - A good building stone should have sufficient hardness.
3) Durability - A good building stones must be durable long lasting nature.
4) Fire resistance - They should have good fire resistance properties.
5) Seasoning/weathering - They also have good weathering resistance properties.
6) Water resistance - They should have less water absorption properties.
7) Economy - They should be economical & easily available.
8) Attrition – A good building stone should have less wear & tear, abrasion & erosion properties.
9) Facing & dressing – A good building stones should be easily molded, craved & dressed.
10) Specific gravity - A good building stone should have higher specific gravity i.e. more than 2.7.
11) Texture – The structure of the good building stone should be compact fine crystalline. They don’t have any cracks, cavities & patches.
12) Toughness - A good building stone should have strong&tough.
Characteristics of stone:-
1) Appearance – Stones should have fine, compact texture & uniform colour.
2) Structure – the structure of stones should be uniform without cracks, fractures, cavities etc.
3) Strength - stone should have better crushing strength i.e. greater than 100 N/mm2
4) Weight – The weight of stones should be considerable & suitable for various construction sites.
Eg. For dam & retaining walls – heavy stones are used
For domes, arches – light stones are used
5) Hardness - stones should have sufficient hardness
6) Toughness - stone should have strong&tough
7) Specific gravity - stone should have higher specific gravity i.e. in between 2.3 to 2.5.
8) Seasoning – stones should be well seasoned
9) Work-ability – Stones should be workable for cutting, dressing with required shapes.
10) Chemical resistance – Stones should resist alkalies, acids, corrosive gases etc
11) Durability - stones should be durable long lasting nature
12) Water resistance - stones should have less water absorption properties
Quarrying and dressing of stone
Quarrying of stones: The method of removal of stones from their natural bed by using different operations is called quarrying.
Methods of Quarrying –
a) Digging – This method is used when the quarry consists of small & soft pieces of stones.
b) Heating – This method is used when the natural rock bed is horizontal & small in thickness.
c) Wedging –This method is used when the hard rock consists of natural fissure. When natural fissures are absent then artificial fissures are prepared by drilling holes.
Wedging required tools –
i) Steel wedge
ii) Conical steel pin or plug
iii) Flat steel wedge
iv) Wooden plug
v) Pneumatic drill
d) Blasting – It is the process of removal of stones with the help of controlled explosives is filled in the holes of the stones. Line of least resistance plays very important role in the blasting process.
Following steps are used in the blasting process:
1) Drilling holes – Blast holes are drilled by using drilling machines.
2) Charging – Explosive powders are fed into the cleaned & dried blast holes.
3) Tamping – The remaining portion of the blast holes are filled by clay, ash, fuse & wirings.
4) Firing –The fuses of blasting holes are fired by using electrical power supply or match sticks.
Dressing of stones:-
Stone dressing tools:-
1) Mason’s hammer
2) Spacing hammer
3) Scabbing hammer
4) Club hammer
5) Soft stone chisel
6) Claw chisel
7) Punching chisel
8) Point chisel
9) Drafting chisel
10) Pitching tool
Seasoning and preservation of stones-The process of removing the sap.
Dry the stones for a period of 6 to 12 months in a shed.The following preservatives are used.
Linsed oil, Solution of alum and soap, Solution of barium hydroxide, Coal tar, paint and Paraffin.
Test on stones – Field tests
- Smith test – It is to check the stones contains muddy substance.
- Toughness test – Stone is hit with hammer and Metallic sound is indication of strong.
- Hardness test – Mohr's hardness is found by scratching the stone by knife.
Test on stones – Laboratory tests.
- Crushing strength test-40x40x40mm cubes are used. Load applied In compression testing machine and the load is 14 Newton / square millimeter. per minute. A stone having 100 Newton/Square Millimeter. is considered as good building stones.
- The water absorption test-A stone is immersed in water for a period of 24 hrs.The water absorption is should not be exceed 0.60
- Attrition test- Los Angeles abrasion test is conducted to find resistance of stones. Los Angeles value for bitumen is 30%. Los Angeles value for base course is 50%.
- Impact test- Recommended values for impact test. For wearing coat – not greater that 30%. For bituminous macadam – not greater than 30%. For water bound macadam – not greater than 40%.
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