2.4. Methods of Combining Aggregates

Try these first

1. 1.

   What does grading refer to in concrete?

   Hint

   Consider how it affects workability.

2. 2.

   What does the trial-and-error method involve?

   Hint

   Think about practical applications.

3. 3.

   What is the primary goal of grading aggregates?

   • To improve appearance
   • To minimize voids and maximize density
   • To reduce weight

   Hint

   Think about the implications for structural integrity.

4. 4.

   True or False: The trial-and-error method is the most efficient way to combine aggregates.

   • True
   • False

   Hint

   Consider other methods discussed.

5. 5.

   Consider an aggregate sample where 50% is larger than 20mm. Analyze the grading and suggest which smaller aggregates should be added to improve workability.

   Hint

   Look for the size range that complements the existing sample.

6. 6.

   You have two aggregates: A has a fineness modulus of 2.5 and B has a fineness modulus of 4.2. If you need a fineness modulus of 3.5, describe the steps to achieve this.

   Hint

   Set up ratios and solve for proportions required.