Download - Stones
STONESa natural, hard substance formed from minerals and
earth material which are present in rocks.
Rock
the portion of the earth’s crust having no definite
shape and structure
IN CONSTRUCTION:
Rock –
An indefinite mixture of naturally occurring substances, mainly minerals.
Its
composition may vary in containment of minerals and organic
substances, and are never exact.
Stone –
Small piece of rock; may or may not refer to ornamental material.
To ease the understanding of this topic, Rock=Stone.
To qualify as a construction material, stone should have
the following qualities:
Strength
Hardness
Durability
Workability
Density
Appearance
Classification of Stones
1. Geological Classification
2. Physical Classification
3. Chemical Classification
1. Igneous Rocks – formed by cooling of magma
a. Plutonic Rocks – Granite
b. Hypabyssal Rocks – Dolerite
c. Volcanic Rocks - Basalt
2. Sedimentary Rocks – formed by deposition of material on
earth’s surface
a. Residual Deposits
b. Sedimentary Deposits
c. Chemical Depositsd. Organic Deposits
Gravel, Sandstone, Limestone, Gypsum, Lignite etc.
3. Metamorphic Rocks – formed by change in character of
pre-existing rocks.
a. Thermal Metamorphism
b. Cataclastic Metamorphism
c. Dynamo-thermal Metamorphism
d. Plutonic Metamorphism
GRANITE
Widely used Plutonic, Unstratified,
Silicious Ingeous rock.
Medium to coarse grained structure.
Hard and Tough
Density – 2.65 to 2.75g/cm3
Compressive Strength – 200 Mpa
Viscosity – 3-6.1019 Pa.s
Melting temperature – 1215 – 1260 0C
Uses
Flooring Tiles
Foundations
Supplants Marble due to acid rain
– used in monuments
Countertops/Platforms in Kitchen.
SANDSTONE
class of rock of cemented silica
grains with texture ranging from
very fine to very coarse. Colors
vary from buff, red and light
brown. Porous where as 30% of
volume composed of pores
LATERITE
Widely used Argillaceous Sedimentary Rock
Contains iron and aluminium oxides – rusty red in color.
Soft and easily broken into smaller pieces.
Brittle – Can be cut into brick-shaped blocks.
Formed in hot and wet tropical areas.
Firm and physically resistant.
Uses
Temples and Monuments.
Crushed Laterite used on road surfaces
QUARTZITE
Metamorphic Rock obtained by heating sandstone under pressure.
Contains various amounts of iron oxide (Fe2O3)
Resistant to Chemical weathering
Uses
Wall Covering
Roofing Tiles
Flooring Tiles
Stair steps
Crushed quartzite is used in road cnst.
MARBLE
Widely used Calcareous Metamorphic Rock
Physically, these are recrystallized, Hard, Compact, fine to very fine grained
metamorphosed rocks capable of taking shining polish.
Hardness - 3 to 4 on Moh's
ScaleDensity - 2.55 to 2.7 Kg/cm3
Compressive Strength - 70 to 140 N/mm2
Uses
Sculpture
Columns
Floors
Pavements
Certain Roofing Materials
SLATEFine grained, foliated, metamorphic
rock
Smooth Flats
Easily Stackable
Uses
Roofing
Floor tiles
Outdoor/Landscape tiles
Wall Cladding
FLAG STONESedimentary rocks split into layers. Consist of feldspar, quartz, arenaceous
Quarried from fissile bedding planes.
Uses
Paving slabs, Walkways, fencing,
Roofing
Used in memorial headstones, facades
Rubble/Aggregate
consists of rough fragments of broken stone that have atleast one good face for exposure in a wall.
Table 1 Common applications of selected stones.
Application Commonly used stones
Exterior wall cladding Granite, marble, limestone
Interior wall cladding Granite, marble, limestone
Interior flooring Granite, marble, slate
Stair treads and risers Granite
Kitchen counter top Granite
Bathroom counter top Granite, marble
Wall copings and balusters Granite, marble, limestone
Roofing Slate
QUARRYING
The process of taking out stones from natural rock bed.It is carried out at ground level in an exposed condition.
Site for quarry
1. Availability of tools, power, materials and labor.2. Availability of site – Avoiding health hazards.3. Distance of site from transportation facilities.4. Drainage of quarry pit.5. Availability of clean water.6. Economy.7. Absence of permanent structures nearby
incase of quarrying by blasting.8. Geological conditions.9. Quality of stone.10. Quantity of stone likely to be obtained.11. Structural stability.12. Check for cracks and fissures.
Methods of Quarrying
1. Quarrying with hand tools
2. Quarrying with channeling machine
3. Quarrying by blasting
Quarrying with hand tools
1. Digging or Excavating
Instruments like pick-axes, hammers, shovels, chisels, etc are used.
Useful in case of soft stones.
2. Heating
Heating the top surface by placing wood or adding fuel
Useful in taking out blocks of more or less regular shapes.
3. WedgingSteel wedges are driven through
cracks and fissures.
Adopted for costly stratified rocks
like laterite, limestone, sandstone.
Quarrying with channeling machineMachines driven by steam, compressed air and electricity.
Channels are cut around the stone block which is to be removed from rock.
The horizontal holes are drilled beneath the block
Wedges are driven into the holes and the block is then broken loose
Adopted for Marble, Limestone and soft sandstone.
Quarrying by blastingUse of explosives.
To obtain small pieces of rock.
Adopted for quarrying hard stones which have no cracks and fissures.
Tools used are; Dipper, Jumper, Priming Needle, Scraping spoon, Tamping bar.
Detonators, Explosives, and Fuses are the materials.
Saves time and labor.
Precautions to be taken seriously.
Dressing of StonesStones are cut in suitable sizes with suitable surfaces are quarrying.
- To get the desired appearance.
- To make transportation easy and economic.
- To suit building requirements.
Some of the variety of finishes are;
1. Axed finish – Dressed by axe. Ex; granite.
2. Boasted finish – Boaster chisel used to make non continuous parallel marks.
3. Dragged finish – Drag is a piece of steel with a number of teeth, rubbed on
the surface in all directions.
4. Furrowed finish – borderline of 20mm is sunk on the edges. A number of
vertical groves are projected out.
5. Hammer-dressed finish – Uneven surfaces and corners.
6. Polished finish – marble, granite.
7. Reticulated finish – net like appearance.
8. Tooled finish – parallel continuous marks are made with a chisel.
Preservations of StonesTo prevent the penetration of moisture to the stone surface.
To avoid develop objectionable color.
To retain the hardness.
1. Coal tar – creates color and spoils the beauty of stone.
2. Linseed oil – Needs to be renewed frequently. Lasts for a longer time.
3. Paint – Changes the color
4. Paraffin
5. Solution of alum and soap.
6. Solution of Barium Hydroxide or Baryta Ba(OH)2
Panelingthin slabs of stone cut to dimension and thickness to cover back
up walls and provide finished exterior
Running Bond - a masonry
bond formed when all units
are laid in stretcher position,
with a half-unit overlap
Stack Bond - a masonry bond
formed when there is no
overlapping of all units and all
horizontal & vertical joints are
aligned
Ashlarswork requires the use of cut stone that includes broken ashlars,
regularly / irregularly coursed.
Coursed Ashlar - Ashlar masonry
laid out in courses of equal
height; blocks of various sizes
may be combined to make up
the height of the course
Random Ashlar - Ashlar masonry
laid without regular courses but
with an overall effect of
horizontal orientation
Rubbleworkrandom & no attempt to produced an orderly course either
horizontal or vertical.. Small spaces are filled with smaller stones.
Coursed Rubble - Fieldstone or
roughly dressed stone, with or
without mortar, assembled to
give a effect of courses
Fieldstone - Stone found on the
ground (i.e., not quarried) that is
a suitable size and shape for use
as drywall or rubble masonry