Lec-9
👉What is Workability Of Concrete?
➡️Workability can be defined as the property of fresh concrete which describes the ease and homogeneity of the concrete to be mixed, fully compacted and finished.
➡️A workable concrete should possess following two requirements:
🚧1. The concrete should be compacted with minimum efforts.
🚧2. The concrete should not form bleeding and segregation.
➡️Workability of concrete mainly depends on the mix proportion and the properties of concreting materials (water, cement, aggregates).
➡️The shape, size, and grades of aggregates also play a great role in the variation of workability.
➡️For better workability fine and coarse aggregates should be well graded.
➡️It has been found that concrete made of round grain sand is more workable than the concrete of crushed sand.
➡️If air entraining admixture is used in the mix, it will also increase the workability and decrease segregation and bleeding.
🏷FACTORS AFFECTING WORKABILITY OF CONCRETE
➡️The factors affecting workability are as following:
🚧1. Amount Of Water In The Mix
🚧2. Proportion Of Coarse And Fine Aggregates: Workability can be increased by decreasing the amount of coarse aggregates in the mix.
*⃣Fine aggregates produce more wore workable concrete.
🚧3. Shape Of aggregates: Round shaped aggregates give better workability than angular shaped aggregates.
🚧4. By expanding the cement content in the mix.
🚧5. By including admixtures in the mix. Apparently, the necessity of workability differs as per the nature of the job and blockage in the full stream of concrete due to the spacing and nature of the reinforcement.
🏷The workability of concrete is generally measured by one of the following three tests
🚧1. Slump Test
🚧2. Compaction Factor Test
🚧3. Vee-Bee Test
#ConcreteTechnology
@Architecturec
👉What is Workability Of Concrete?
➡️Workability can be defined as the property of fresh concrete which describes the ease and homogeneity of the concrete to be mixed, fully compacted and finished.
➡️A workable concrete should possess following two requirements:
🚧1. The concrete should be compacted with minimum efforts.
🚧2. The concrete should not form bleeding and segregation.
➡️Workability of concrete mainly depends on the mix proportion and the properties of concreting materials (water, cement, aggregates).
➡️The shape, size, and grades of aggregates also play a great role in the variation of workability.
➡️For better workability fine and coarse aggregates should be well graded.
➡️It has been found that concrete made of round grain sand is more workable than the concrete of crushed sand.
➡️If air entraining admixture is used in the mix, it will also increase the workability and decrease segregation and bleeding.
🏷FACTORS AFFECTING WORKABILITY OF CONCRETE
➡️The factors affecting workability are as following:
🚧1. Amount Of Water In The Mix
🚧2. Proportion Of Coarse And Fine Aggregates: Workability can be increased by decreasing the amount of coarse aggregates in the mix.
*⃣Fine aggregates produce more wore workable concrete.
🚧3. Shape Of aggregates: Round shaped aggregates give better workability than angular shaped aggregates.
🚧4. By expanding the cement content in the mix.
🚧5. By including admixtures in the mix. Apparently, the necessity of workability differs as per the nature of the job and blockage in the full stream of concrete due to the spacing and nature of the reinforcement.
🏷The workability of concrete is generally measured by one of the following three tests
🚧1. Slump Test
🚧2. Compaction Factor Test
🚧3. Vee-Bee Test
#ConcreteTechnology
@Architecturec
Lec-10
👉Some Questions
🏷
➡️Q1. What is the Unit Weight of concrete?
🚧The unit weight of concrete depends on the type of aggregates and amount of voids.
*⃣As per IS : 456-200 Unit weight of PCC is 24KN/m3 and RCC is 25KN/m3
➡️Q2. What is the unit weight of Steel?
🚧The unit weight of Steel is 78.5KN/m3
➡️Q3. What is ductility?
🚧Ductility is the Ability to deform under tensile stress.
➡️Q4. How to find the weight of steel bar used in reinforcement?
🚧Weight of Bar in kg/m = Dsquare/162.2
*⃣D- Dia of bar in mm
➡️Q5. What’s the difference between one way slab and two-way slab?
🚧One way slab: Ratio of Longer Span / Shorter span > 2
🚧Two way slab: Ratio of Longer span/ shorter span <= 2
➡️Q6. What is flat slab?
🚧The slab which is supported on columns (Flab slab don’t have beams)
➡️Q7. What do you mean by One storeyed, Two storeyed building?
🚧The building which has two floors is called two storeyed building.
➡️Q8. What’s the length of rise and tread in Stair case?
🚧Rise – 150mm to 200mm
🚧Tread – 250mm to
300mm
➡️Q9. What’s the slope of Staircase?
🚧As per IS 456, the slope or pitch of stair should be between 25 degrees to 40 degrees.
➡️Q10. What do you mean by the moment of inertia?
🚧A quantity expressing a body’s tendency to resist angular acceleration, which is the sum of the products of the mass of each particle in the body with the square of its distance from the axis of rotation.
➡️Q11. What is a crank length in the slab?
🚧The crank length in Slab is 0.42 D.
*⃣Where D is Depth of Slab- Top cover – Bottom Cover.
➡️Q12. What are the types of a slump?
🚧True Slump: The concrete mass after the test when slumps evenly all around without disintegration is called the true slump.
🚧Shear Slump: When one half of the concrete mass slide down the other is called the shear slump.
*⃣This type of slump is obtained in a lean concrete mix.
🚧Collapse Slump: When the sample is collapsed due to adding excessive water, it is known as collapse slump.
🚧Zero Slump: For very stiff or dry mixes it does not show any changes of The slump after removing the slump cone.
➡️Q13. What is grouting?
🚧Grout is a fluid form of concrete which is used to fill the voids.
@Architecturec
@Architecturec
@Architecturec
👉Some Questions
🏷
➡️Q1. What is the Unit Weight of concrete?
🚧The unit weight of concrete depends on the type of aggregates and amount of voids.
*⃣As per IS : 456-200 Unit weight of PCC is 24KN/m3 and RCC is 25KN/m3
➡️Q2. What is the unit weight of Steel?
🚧The unit weight of Steel is 78.5KN/m3
➡️Q3. What is ductility?
🚧Ductility is the Ability to deform under tensile stress.
➡️Q4. How to find the weight of steel bar used in reinforcement?
🚧Weight of Bar in kg/m = Dsquare/162.2
*⃣D- Dia of bar in mm
➡️Q5. What’s the difference between one way slab and two-way slab?
🚧One way slab: Ratio of Longer Span / Shorter span > 2
🚧Two way slab: Ratio of Longer span/ shorter span <= 2
➡️Q6. What is flat slab?
🚧The slab which is supported on columns (Flab slab don’t have beams)
➡️Q7. What do you mean by One storeyed, Two storeyed building?
🚧The building which has two floors is called two storeyed building.
➡️Q8. What’s the length of rise and tread in Stair case?
🚧Rise – 150mm to 200mm
🚧Tread – 250mm to
300mm
➡️Q9. What’s the slope of Staircase?
🚧As per IS 456, the slope or pitch of stair should be between 25 degrees to 40 degrees.
➡️Q10. What do you mean by the moment of inertia?
🚧A quantity expressing a body’s tendency to resist angular acceleration, which is the sum of the products of the mass of each particle in the body with the square of its distance from the axis of rotation.
➡️Q11. What is a crank length in the slab?
🚧The crank length in Slab is 0.42 D.
*⃣Where D is Depth of Slab- Top cover – Bottom Cover.
➡️Q12. What are the types of a slump?
🚧True Slump: The concrete mass after the test when slumps evenly all around without disintegration is called the true slump.
🚧Shear Slump: When one half of the concrete mass slide down the other is called the shear slump.
*⃣This type of slump is obtained in a lean concrete mix.
🚧Collapse Slump: When the sample is collapsed due to adding excessive water, it is known as collapse slump.
🚧Zero Slump: For very stiff or dry mixes it does not show any changes of The slump after removing the slump cone.
➡️Q13. What is grouting?
🚧Grout is a fluid form of concrete which is used to fill the voids.
@Architecturec
@Architecturec
@Architecturec