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Materials of Construction-Building Stones 1
BUILDING STONES
Chapter 4
Wikipedia.org
Materials of Construction-Building Stones 2
What is Stone?
Stone is a concretion of mineral matter.
Used either as a;
Construction material,
Manufacture of other construction materials.
Stone has high strength, durability and nice
appearance.
Materials of Construction-Building Stones 3
Uses in Construction
Building walls, bridges, dams,
Road surfacing, (blocks or crushed rock)
Aggregate in concrete.
Materials of Construction-Building Stones 4
Stone / Rock
These are often used synonymously. However;
Rocks are made up of one or more minerals which have definite chemical compounds. These minerals usually have crystalline structures, but some consist of a natural non-crystalline structure.
Stone is used to define quarried or small pieces of rock for a specified function such as a building block, a paving block, etc.
Materials of Construction-Building Stones 5
Geological Classification of Rocks
• Igneous,
• Sedimentary,
•Metamorphic.
Materials of Construction-Building Stones 6
Igneous Rocks
Formed by cooling and solidification from a molten state
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Materials of Construction-Building Stones 7
Materials of Construction-Building Stones 8
Igneous Rocks
1. Intrusive Rocks: Slowly crystallized within the earth
2. Extrusive (volcanic) Rocks: Rapidly crystallized due to fast cooling on the surface of the earth
3. Pyroclastic Rocks: Formed after sudden eruption, include volcanic ash composed of fine amorphous particles.
Materials of Construction-Building Stones 9
Sedimentary Rocks
Sediments are transported, deposited and solidified through pressure exerted by overlying material or by the action of natural agents.
stloe.most.go.th
Materials of Construction-Building Stones 10
Metamorphic Rocks
Formed by gradual changes
in the structures of either
igneous or sedimentary
rocks caused by the action
of heat, pressure, water
etc.
stloe.most.go.th
Materials of Construction-Building Stones 11
Important Rock Types used as
Construction Material
Wikipedia.org
Materials of Construction-Building Stones 12
Granite
Coarsely crystalline intrusive rock.
Contains silica in the form of quartz, feldspar and mica
Red, pink, gray, brown
Strong, hard, non- porous
Used in flooring, interior or exterior wall facing, column facing, stair treads.
beg.utexas.edu
Materials of Construction-Building Stones 13
Basalt
Finely crystalline
extrusive rock which
occurs as lava sheets.
Dark colored,
Basalt is also a hard
and strong rock, but it
is likely to somewhat
porous and fractured.
beg.utexas.edu
Materials of Construction-Building Stones 14
Limestone
Sedimentary rock
composed mainly of CaCO3
Limestones containing
considerable amount of
magnesium carbonate are
dolomitic limestones.
Used as: concrete
aggregate, raw material in
cement production, flux in
the produciton of pig iron..
mii.org
Materials of Construction-Building Stones 15
Travertine
Sedimentary rock,
composed mainly of
calcium carbonate
Off-white, gray, light
to dark tan
Used as: interior
decorative stone,
due to its pleasing
texture
Materials of Construction-Building Stones 16
Sandstone
Sedimentary rock made of grains of sand cemented and compacted to form a solid rock.
SiO2 & Al2O3; cementing material may either be calcium carbonate or clayey matter.
Used as facing material
Alpinequarries.com
Wikipedia.org
Materials of Construction-Building Stones 17
Marble
Metamorphosed limestone, more
crystalline and harder than
limestone.
Great range of colors
Hard and strong rock which can
hold polish well.
May weather easily, used for
interior work such as wall,
column facing, flooring
Wikipedia.org
Materials of Construction-Building Stones 18
Slate
Metamorphosed clay
SiO2, Al2O3, Fe2O3, K2O, MgO
Black, green, gray, red and purple. .
Can be separated into thin sheets with smooth surfaces.
Tough, strong and non-absorptive.
Used for flooring, interior or exterior wall facing, window sills, and roofing.
Materials of Construction-Building Stones 19
Production of Building Stones
Quarrying: Overburden of soil or inferior stone is first removed from the surface. Large blocks of stone (1X1.5X3 m) are cut, loosened at the bottom by wedging and removed by cranes.
Shaping and finishing: Large blocks of stone are cut to desired shape and given whatever degree of finishing is desired.
Materials of Construction-Building Stones 20
Selection of Building Stones
Durability, appearance and cost are
important parameters.
Durability, temperature changes, average
humidity of the atmosphere, fire and
abrasion resistance (related to hardness)
are important.
Materials of Construction-Building Stones 21
Durability
The durability of a stone is its ability to resist weathering action, chemical attack, abrasion, frost, heat and other service conditions.
Both durability and the strength of a stone are affected by the texture, mineral composition, chemical and physical characteristics.
Materials of Construction-Building Stones 22
Strength
(a) the mineral composition
(b) the rate of cooling (grain size) of the igneous rocks
(c) the manner of formation and the size of the component crystals of sedimentary rocks
(d) the type and degree of metamorphism of metamorphic rocks.
Therefore, the strengths of stones show great variations. (from low values up to 3500 kgf/cm2)
Materials of Construction-Building Stones 23
Materials of Construction-Building Stones 24
Strength
The compressive strength of stone is important to support foundations or in stone masonry. However, the compressive strength of most stones is sufficiently high to be used in structures.
The strength of stone masonry is much less than the strength of stone itself, the exact strength depending on the width of the joint and the type of mortar used.
The tensile and the flexural strength of stone are much lower than its compressive strength.
Materials of Construction-Building Stones 25
Porosity & Water Absorption
The water absorption capacity of stone is related to its
porosity (amount of permeable pores)
The presence of permeable pores also affects the frost
resistance of stones. When water gets in the pores and
freezes, the ice exerts some internal pressure. Alternate
freezing and thawing processes cause cracking of stones.
total
poresof
V
VPorosity
100%, xstoneofweightDry
absorbedwaterofWeightAbsorption
Materials of Construction-Building Stones 26
Strength vs Absorption of Stone
Materials of Construction-Building Stones 27
Coefficient of Expansion
Stones expand upon being heated.
However, unlike most materials, they do not
return to their original volume when cooled
after heating. They show a small amount (0.02
to 0.04%) of permanent swelling.
The coefficient of expansion of a stone affects its
expansion upon being heated, and contraction
when cooled.
Materials of Construction-Building Stones 28
Physical Properties of Dry
Building Stones
Ultimate
Compressive
Str. (MPa)
Weight
(g/cm3)
Porosity
(%)
Coeff. Of
Expansion
(10-6/OC)
Granite 100-210 2.50-2.83 0-1 5.58-7.56
Marble 70-180 2.56-2.72 0.2-0.6 3.6-10.08
Limestone 30-140 2.23-2.69 0.3-2.0 1.8-8.46
Sandstone 50-140 2.13-2.56 5-28 0.4-4.5
Slate 50-210 2.75-2.83 0.1-0.7 12.6-18
Materials of Construction-Building Stones 29
Fire Resistance
The cause of damage in stone under high temperatures is the disintegration that occurs because of the internal stresses due to unequal expansion of unequally heated portions of the stone.
Limestone suffers little until a temperature of somewhat above 700°C is reached, at this point it decomposes (CO2 is driving off).
Sandstones suffer least from fire if they are dense and non-porous
Granites and marbles suffer great from fire.
Materials of Construction-Building Stones 30
Cast or artificial stone is a masonry product made of concrete. The surface may include granite, quartz, marble, etc. The textures may be smooth, polished, colored or uncolored.
Synthetic stone is made from minerals and a polyester plastic binder. For example, synthetic granite is produced using approximately 50% fine grained granite, 30% fine silica sand and 20% polyester resin. Synthetic marble is produced by combining approximately 80% fine silica sand, 2-3% pigment and 17-18% polyester resin (no marble!).
Caststone.org
Materials of Construction-Building Stones 31
Example
Two rock samples A and B have the following characteristics
Calculate the capillary porosity, permeable and impermeable pore percentages of the two rocks. Which rock is more permeable?
For Rock A
V=875/2.5=350 cm3
a) capillary porosity=12 cm3/350=0.0344=3.44%
b) permeable porosity=41/350=0.117=11.7%
c) total porosity=1-(2.5 g/cm3/2.9x1 g/cm3)=0.14=14%
Since total porosity=permeable porosity+impermeable porosity
d) impermeable porosity=0.14-0.117=0.023 (2.3%)
For Rock B
V=800/2.3=348 cm3
a) capillary porosity=10 cm3/348=0.0286
b) permeable porosity=35/348=0.100=10%
c) total porosity=1-(2.3/2.85)=0.2=20%
d) impermeable porosity=0.2-0.1=0.1 (10%)
Permeabilty of rock is controlled by its permeable porosity since A rock has a higher permeable porosity, it is expected that it will have higher permeability.
Dry weight of
sample (g)
Water absorption
by capillarity (g)
Absorption
capacity (g)
Unit weight
(g/cm3)
Specific
gravity
Rock A 875 12 41 2.5 2.9
Rock B 800 10 35 2.3 2.85