Stones

Question 1

DIFERENT KIND OF STONES

Answer 1

Artificial stones
The qualities required can be
controlled by the selection of
raw materials

• Defined properties
• Definition of the properties

Natural stones

• Natural stones are extracted from stone quarries.
• Varying mechanical and physical properties
• Requires precise selection.

Question 2

Dry stone walls

Answer 2

building method by which structures are constructed from stones without any mortar to bind them together.
It works by carefully-selected interlocking stones

Question 3

Ashler

Answer 3

Ashlar is prepared stone work of any type of stone.
Ashlar blocks were used in the construction of normally very old buildings like castles.

Generally the external face is smooth or polished.

Question 4

Jointed brick

Answer 4

Joint bricks masonry is a structure of individual units laid in and bound together by mortar.

• Masonry is very heat resistant good fire protection.
• Masonry walls are better resistant to hurricanes or tornadoes

Question 5

Rubble stone.

Answer 5

• Rubble masonry is rough and not laid in regular courses
• The stones can be bonded with mortar
• This stone the scrap left over from processing.

Question 6

Stone finishes

Answer 6

1. Polished finish - a glossy surface
2. Hone finish - a satin smooth surface finish
3. Thermal finish - intense heat flaming.
4. Diamond sawed
5. Rough sawn
6. Bush-hammered

Question 7

Fields of application

Answer 7

1. Masonry
2. Façade lining
3. Roof covering
4. Road construction
5. Concrete production

Question 8

Methods of manufacture

Answer 8

Bricks may be made from:

• clay, shale,
• soft slate,
• calcium silicate,
• concrete

Three processes :

• soft mud,
• dry press, or
• extruded.

Question 9

Burned Bricks

Answer 9

basic materials are clay and loam

Production:

• Grinding and mixing of raw materials
• Forming of the bricks
• Drying of the formed bricks
• Burning of the bricks in tunnel kiln at 900°C – 1500°C for 1-3 days

Question 10

Bricks classification

Answer 10

• Compressive Strength
• Density
• Dimensions

Question 11

Bricks important qualities

Answer 11

• Compressive strength
• Heat insulating value and heat storage capacity
• Water-absorption and water-permeability
• Vapor permeability
• Resistance against weather, chemicals and fire

Question 12

Mud bricks

Answer 12

• raw clay + 25-30% sand to reduce shrinkage.
• The clay is first ground and mixed with water
• The clay is then pressed into steel moulds
• The shaped clay is fired (“burned”) at 900-1000 °C to achieve strength.

Question 13

Dry pressed bricks

Answer 13

• start with a much thicker clay mix, so it forms more accurate, sharper-edged bricks.
• The greater force in pressing and the longer burn make this method more expensive.

Question 14

Extruded bricks

Answer 14

• clay is mixed with 10-15% water
• drying for between 20 and 40 hours at 50-150 °C

Question 15

Calcium silicate bricks

raw materials

Answer 15

• lime mixed with quartz,
• crushed flint or crushed siliceous
• mineral colourants.

Question 16

Calcium silicate bricks

advantages

Answer 16

• The finished bricks are very accurate and uniform
• The bricks can be made in a variety of colours

Question 17

Mechanical and Physical Properties of Burned Bricks

Answer 17

• Water absorptive capacity:

up to 15% by weight (control of interior climate)

• Heat insulation intermediate but good heat storage capacity
• Light weight bricks half density by same strength
• High-strength bricks and clinkers:

Density > 1.4 kg/dm3

• Resistance to frost:

T > 1100°C, density > 1.9 kg /dm3 and compressive strength > 35 MPa are frost resistant

Question 18

Lime Sand Stones

Answer 18

Basic materials are silica, hydrated lime and water

Question 19

Lime Sand Stones Production

Answer 19

1. mixing of sand, hydrated lime and water
2. Forming of bricks by pressing material in to shape
3. Curing in an atmosphere of steam (175 – 210°C) at
   pressure of 0.9 – 1.7 MPa. Duration 4 to 8 hours.