LESSON 3

• PHYSICAL PROPERTIES - These are the properties required to estimate the quality and condition of the material without any external force.
• PHYSICAL PROPERTIES OF ENGINEERING MATERIALS

  ➢ Bulk density

  ➢ Porosity

  ➢ Durability

  ➢ Specific gravity

  ➢ Fire resistance

  ➢ Weathering resistance

  ➢ Water absorption

  ➢ Water permeability
• Bulk Density - is the ratio of mass to the volume of the material in its natural state that is including voids and pores.
• Bulk Density - It is expressed in kg/m3.
• Bulk Density - influences the mechanical properties of materials like strength, heat and conductivity etc.
• Porosity - gives the volume of the material occupied by pores.
• Porosity - It is the ratio of volume of pores to the volume of material.
• Porosity - influences many properties like thermal conductivity, strength, bulk density, durability etc.
• Durability - The property of a material to withstand against the combined action of atmospheric and other factors.
• Durability - If the material is more durable, it will be useful for longer life.
• Maintenance cost of material is dependent of durability.
• Specific Gravity - (Relative Density) is the ratio of mass of given substance to the mass of water at 4°C for the equal volumes.
• Fire Resistance - The ability to withstand against fire without changing its shape and other properties.
• Fire resistance of a material is tested by the combined actions of water and fire.
• Fire Resistance - Fireproof materials should provide more safety in case of fire.
• Weathering Resistance - The property of a material to withstand against all atmospheric actions without losing its strength and shape.
• Weathering Resistance - Weathering effects the durability of material.
• Weathering effects the durability of material.
• Weathering Resistance - For example corrosion occurs in iron due to

  weathering. To resist this, paint layer is provided.
• For example corrosion occurs in iron due to weathering. To resist this, paint layer is provided.
• Water Absorption - The capacity of a material to absorb and retain water in it.
• Water Absorption - It is expressed in % of weight of dry material.
• Water Absorption - It depends up on the size, shape and number of pores of material
• Water Permeability - The ability of a material to permit water through it.
• Dense materials like glass metals etc. are called impervious materials which cannot allow water

  through it.
• Mechanical properties of the materials are found out by applying external forces on them.
• MECHANICAL PROPERTIES - These are very important properties which are responsible for behavior of a material in its job.
• MECHANICAL PROPERTIES

  ➢ Strength

  ➢ Hardness

  ➢ Elasticity

  ➢ Plasticity

  ➢ Brittleness

  ➢ Fatigue

  ➢ Impact Strength

  ➢ Abrasion Resistance

  ➢ Creep
• Strength - The capacity of a material to resist failure caused by loads acting on it.
• Strength - The load may be compressive, tensile or bending.
• In strength, the load may be compressive, tensile or bending.
• Strength - It is determined by dividing the ultimate

  load taken by the material with its cross sectional area.
• Strength is an important property for any construction materials.
• So, to provide maximum safety in strength, factor of safety is provided for materials and it is selected depending on nature of work, quality of material,

  economic conditions etc.
• Hardness - The property of a materials to resist scratching by a harder body.
• MOHS scale is used to determine the hardness of a materials.
• Hardness is most important to decide the usage of

  particular aggregate.
• Hardness - It also influences the workability.
• Elasticity - The capacity of a material to regain its initial shape and size after removal of load.
• The capacity of a material to regain its initial shape and size after removal of load is known as

  elasticity and the material is called as elastic material.