2.3. Grading of Aggregates

Try these first

1. 1.

   What is grading in terms of aggregates?

   Hint

   Think about how different sizes affect concrete.

2. 2.

   Name the two main categories of aggregates.

   Hint

   Consider their size relative to the 4.75 mm sieve.

3. 3.

   What is the primary goal of aggregate grading?

   • To achieve maximum voids
   • To minimize voids
   • To maximize surface area

   Hint

   Think about how packing affects concrete quality.

4. 4.

   True or False: Coarse aggregates are those that pass through a 4.75 mm sieve.

   • True
   • False

   Hint

   Recall the definitions based on sieve sizes.

5. 5.

   A concrete mix design is planned using aggregates classified as Zone III. Discuss the expected properties and challenges of using these aggregates compared to those from Zone I.

   Hint

   Consider how the void content and aggregate size affect the concrete's water requirement.

6. 6.

   Calculate the grading of an aggregate blend using 60% fine aggregates (Zone II) and 40% coarse aggregates (Zone I). Discuss how this blend may perform in terms of workability and strength.

   Hint

   Focus on how the proportion of sizes impacts concrete performance.