Characteristic of good building Stone
Following are the characteristic
of good building stone.
1 Appearance.
This property of stone is very impotent for face work of building
For architectural point of view color of the
stone should well and matching with surrounding.
The lighter
color stone should be preferred to dark
ones.
Because dark
color stone are less durable than the lighter due to the presence of oxide of iron.
Due to the presence of oxide of iron there are chances to disfigure the stone
with rust stain and to disintegrate it.
2 General Structure. When stone broken in
a direction should not give dull in appearance. It should show uniform of
texture, crystalline homogenous, close and fine grained. It must be either free
from cavity, crack, or pitches of soft are lose material. All the
stratification should not be visible with the naked eye except difference in
color.
3 Heaviness.
Heavier varieties of Stone are very important. It means the stone are more
compact, less porous and greater specific gravity. Heaver varieties of stone
use in water like Dam, barrages, weirs, docks, harbors, and retaining walls. The stones used for roof
coverings should be heavier one. A stone should have specific gravity between
2.4 - 2.8.
4 Strength. Generally compressive
strength is needed. Igneous rock stones are stronger than those of sedimentary
rock stone. Usually in construction the stone are use quite strong to stand
against the force likely to counter yet. The stone that use in Construction
where heavy load and pressure likely to come should tested for its strength.
5 Hardness.
Hardness is the Resistance of stone to abrasive force caused by much wear and
friction as in pavement, floor, and aprons of bridges and weir, abutment in river.
6 Toughness.
Toughness is the resistance of stone to stand
against vibration. This type of stone used at places subject to vibrations,
moving and dead loads should be tough.
7 Easy
of working. The stone used
in making statues (cut, dressed, molded, and carved) like structure should be
good enough to be converted into certain shape. Marble is one of the examples
but it should be noted that this quality is opposed to strength, hardness and durability.
8 Porosity and absorption Exposed surface
absorbs rain water which forms acids causing crumbling action. Porous
stones are unsuitable for the construction works less porous stones
absorb less fluid hence are more durable. In cold climatic regions water may ingress into the pores and
freeze in this way the volume of freeze water increase and the result is
disintegrate of stone.
9 Seasoning.
All freshly quarried stone have certain amount of moisture known is quarry sap,
which is make them soft and easier to work upon them such is dressing, carving
and molding. All these work should
be done early after quarrying. After querying when has been done upon stone,
they should be left for seasoning a period of 6-12 month under the shed having
no wall with free circulation of air.
Suitability Stones for Various types of Construction.
S.N.
|
Type of structure
|
Type of stone
|
1
|
Piers, bridge abutments, light houses, and wires.
|
Good quality granite, good or stratified granite.
|
2
|
Road Pavements and railway
ballast
|
Inferior quality of granite
and Gneiss.
|
3
|
Road metalling, Paving
|
Basalt and Trap.
|
4
|
Cement concrete
|
Basalt and Trap.
|
5
|
Ornamental work in building
|
Red and yellow types of basalt and trap.
|
6
|
Roof Covering and Flooring
|
Slate
|
7
|
Damp proofing and sills of windows
|
Slate
|
8
|
Partitions in urinals and
bath rooms
|
Slate
|
9
|
Monuments, Statues and carved work
|
Marble
|
10
|
Building Construction
|
Laterite
|
11
|
Interior decoration in superior buildings
|
Serpentine
|
Cursing Strength (Kg/cm) and Specific Gravity of various types of
stones
Stones
|
Specific gravity
|
Crushing strength
(kg/cm2)
|
Granite
|
2.63-2.65
|
1000-1400
|
Basalt
|
3.00
|
700-850
|
Sandstone
|
2.3-2.6
|
400-650
|
Limestone
|
2.3-2.4
|
400-650
|
Marble
|
2.72
|
500-600
|
Slate
|
2.89
|
750-2100
|
Quartz
|
2.65
|
750
|