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Questions and Answers
What is the purpose of aggregates in concrete production?
What is the purpose of aggregates in concrete production?
Aggregates are used as filler with binding material in the production of mortar and concrete.
Which of the following are requirements of good aggregate? (Select all that apply)
Which of the following are requirements of good aggregate? (Select all that apply)
Aggregates should not absorb water more than ______ from added water.
Aggregates should not absorb water more than ______ from added water.
0.5 - 1%
What is classified as coarse aggregate?
What is classified as coarse aggregate?
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Which of the following describes fine aggregates?
Which of the following describes fine aggregates?
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What type of sources can aggregates be derived from?
What type of sources can aggregates be derived from?
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Aggregates should absorb more than 1% water to be considered good.
Aggregates should absorb more than 1% water to be considered good.
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What are aggregates used for in the production of concrete?
What are aggregates used for in the production of concrete?
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Which of the following are requirements of good aggregate? (Select all that apply)
Which of the following are requirements of good aggregate? (Select all that apply)
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Coarse aggregate has a size greater than 4.75 mm.
Coarse aggregate has a size greater than 4.75 mm.
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The aggregate having a size of less than 4.75 mm is called __________.
The aggregate having a size of less than 4.75 mm is called __________.
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What are the natural sources of aggregates?
What are the natural sources of aggregates?
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What is one of the primary purposes of fine aggregates?
What is one of the primary purposes of fine aggregates?
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What should the water absorption of aggregates not exceed?
What should the water absorption of aggregates not exceed?
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Study Notes
Aggregates in Concrete Technology
- Aggregates serve as fillers in mortar and concrete production, constituting 70-80% of concrete volume.
- Essential characteristics of good aggregates include cleanliness, hardness, strength, durability, and appropriate grading.
Source of Aggregates
- Natural Sources: Found in river basins, sea beds, bedrock. Examples include gravel, sand, and crushed rocks like granite.
- Artificial Sources: Man-made from waste materials such as broken bricks, air-cooled blast furnace slag, sintered fly ash, and bloated clay.
Requirements of Good Aggregate
- Strength: High crushing strength is required to withstand stresses from traffic loads.
- Hardness: Should resist abrasion effectively.
- Durability: Capable of withstanding weathering effects, such as rain and temperature variations.
- Workability: Should facilitate easy mixing, transporting, placing, and finishing.
- Shape: An angular shape ensures strong interlocking.
- Texture: Rough texture promotes better bonding in the concrete mix.
- Water Absorption: Should limit absorption to 0.5-1% to maintain a consistent water-cement ratio.
- Purity: Free from organic and inorganic impurities to ensure quality.
Classification of Aggregates by Size
-
Coarse Aggregates:
- Size ranges from 4.75 mm to 80 mm.
- Sourced from natural disintegration or artificial crushing of rocks.
-
Fine Aggregates:
- Size less than 4.75 mm.
- Obtained from rivers and crushed stones.
- Smallest size (sand) is 0.075 mm.
- Passes through a 4.75 mm sieve and retained on a 75 µm sieve.
- Functions to fill voids and enhance workability.
Types of Fine Sand
- Coarse Sand: Size between 4.75 mm and 2 mm.
- Medium Sand: Size between 2 mm and 0.425 mm.
- Fine Sand: Typically varies below 0.425 mm, specific classifications may apply.
Aggregates in Concrete Technology
- Aggregates serve as fillers in mortar and concrete production, constituting 70-80% of concrete volume.
- Essential characteristics of good aggregates include cleanliness, hardness, strength, durability, and appropriate grading.
Source of Aggregates
- Natural Sources: Found in river basins, sea beds, bedrock. Examples include gravel, sand, and crushed rocks like granite.
- Artificial Sources: Man-made from waste materials such as broken bricks, air-cooled blast furnace slag, sintered fly ash, and bloated clay.
Requirements of Good Aggregate
- Strength: High crushing strength is required to withstand stresses from traffic loads.
- Hardness: Should resist abrasion effectively.
- Durability: Capable of withstanding weathering effects, such as rain and temperature variations.
- Workability: Should facilitate easy mixing, transporting, placing, and finishing.
- Shape: An angular shape ensures strong interlocking.
- Texture: Rough texture promotes better bonding in the concrete mix.
- Water Absorption: Should limit absorption to 0.5-1% to maintain a consistent water-cement ratio.
- Purity: Free from organic and inorganic impurities to ensure quality.
Classification of Aggregates by Size
-
Coarse Aggregates:
- Size ranges from 4.75 mm to 80 mm.
- Sourced from natural disintegration or artificial crushing of rocks.
-
Fine Aggregates:
- Size less than 4.75 mm.
- Obtained from rivers and crushed stones.
- Smallest size (sand) is 0.075 mm.
- Passes through a 4.75 mm sieve and retained on a 75 µm sieve.
- Functions to fill voids and enhance workability.
Types of Fine Sand
- Coarse Sand: Size between 4.75 mm and 2 mm.
- Medium Sand: Size between 2 mm and 0.425 mm.
- Fine Sand: Typically varies below 0.425 mm, specific classifications may apply.
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Description
This quiz covers the fundamental aspects of aggregates in concrete technology. Learn about the sources of aggregates, their essential characteristics, and what makes a good aggregate for construction purposes. Test your knowledge on natural and artificial aggregates and their properties.
