ATT Sieve Analysis & Gradation 3

Question 1

According to ASTM C136, the minimum sample mass for sieve analysis of a coarse aggregate with a nominal maximum size of 1½ in. (37.5 mm) is approximately:

Accepted Answer

15 kg (33 lb)

Answer

ASTM C136 Table 2 requires approximately 15 kg for nominal maximum size of 37.5 mm (1½ in.) to ensure a representative sample.

Question 2

On a gradation chart, a well-graded aggregate will appear as:

Accepted Answer

A relatively smooth S-shaped curve spanning a wide range of sizes

Answer

A well-graded aggregate has particles distributed across a wide range of sizes, producing a smooth S-shaped curve on a percent-passing gradation chart.

Question 3

When combining two aggregate stockpiles to achieve a desired gradation, the method used to calculate the blend proportions is called:

Accepted Answer

The diagonal method or trial-and-error blending

Answer

Aggregate blending typically uses the diagonal method (graphical) or trial-and-error calculations to determine proportions that meet specification gradation limits.

Question 4

The percent retained on a given sieve is calculated by dividing the mass retained on that sieve by:

Accepted Answer

The total original dry sample mass

Answer

Percent retained = (mass retained on sieve / total original dry sample mass) × 100, using the total original sample as the denominator.

Question 5

ASTM C33 specifies gradation requirements for concrete aggregates. For coarse aggregate Size No. 57, the nominal size range is:

Accepted Answer

1 in. to No. 4 (25.0 mm to 4.75 mm)

Answer

ASTM C33 Size No. 57 coarse aggregate has a nominal size range of 1 in. to No. 4 (25.0 mm to 4.75 mm).

(ATT) ACI Aggregate Testing Technician Practice Test

(ATT) ACI Aggregate Testing Technician Practice Test

ATT Sieve Analysis & Gradation 3