MECHANICS OF SOLIDS

PROPERTIES OF MATERIALS 

1. STRENGTH : Ability to withstand mechanical load.

2. HARDNESS: Ability to resist scratching, abrasion, cutting or penetrations.

3. DUCTILITY: Ability to deform like wires under tensile strength.

4. TOUGHNESS: Ability to absorb energy upto fracture.

5. ELASTICITY: Ability to return to its original position after deformation.

6. DENSITY: Ratio of mass of the material to its volume in homogeneous state.

7. MALIABILITY: Ability to form thin sheet without failure.

8. PLASTICITY: Ability to deform permanently without rupture.

9. BRITTLENESS: Ability to suddenly break into small pieces without deformation.

10. STIFFNESS: Ability to resist mechanical deformation.

11. CORROSION: Ability to resist environmental attack and decay.

12. CONDUCTIVITY: Ability to conduct electricity and heat.

13. DIELECTRIC: Ability to withstand at high voltage.

14. DIAMAGNETISM: Ability to repelled from the magnet.

Stress = Resistive Force/Area

Unit=N/mm2 or Pascal

1N/mm2 = 10^6 N/m2 = 1MPa

Strain = Change in dimension / Original Dimension

Unit=No unit

BRICKS

COMPOSITION OF BRICK

1. SILICA -50 to 60% 

• Prevents shrinking, cracking and warping
• Impart uniform shape
• Makes the brick durable and heat resistant
• Excess silica results in making the brick brittle and weak

 2. ALUMINA -20 to 30%

• Chief ingredient
• Impart plasticity for easy molding
• Excess alumina results in making the brick shrink and wrap during drying and molding

3. LIME - up to 5%

• Prevents shrinkage of row brick
• Excess lime results in making the brick to melt and distort

4. IRON OXIDE - 5 to 6%

• Imparts red color to bricks
• Excess iron oxide results in making the brick blue or blackish
• Less iron oxide results in making the brick yellowish in color

5. MAGNESIA - small quantity

• Imparts yellow color to bricks
• Decrease shrinkage
• Excess magnesia results in decaying of brick

HARMFUL INGREDIENTS

1. ALKALIES

• It absorb moisture from air and form white crystalline substance called efflorescence

2. IRON PYRITES

3. PEBBLES

4. VEGETATION AND ORGANIC MATTER

STONES

CLASSIFICATION OF STONES

A. GEOLOGICAL CLASSIFICATION

B. PHYSICAL CLASSIFICATION

C. CHEMICAL CLASSIFICATION 

TEST OF STONES

1. ACID TEST

• To check weather resistance
• Dipping the specimen in hydrochloric acid for three days
• If a white specimen formed in the specimen, indicates the presence of calcium carbonate which showing that the stone have poor weathering capacity

2. ATTRITION TEST

• To check wear stones used in road construction
• Carried out in Deval's attrition test machine

3. CRUSHING TEST

• It is the maximum area at which its samples crushes or fails divided by the area of the bearing face of the specimen
• Specimen Size = 4cm x 4cm x 4cm
• Number of specimen = 3