ACI Aggregate Properties and Testing Questions and Answers

Question 1

According to ASTM C136/C136M, what is the primary reason for performing a sieve analysis on fine and coarse aggregates?

Accepted Answer

To determine the particle size distribution (grading) of the aggregate

Answer

To determine the moisture content of the aggregate

Answer

To measure the resistance of the aggregate to abrasion

Answer

To calculate the specific gravity of the aggregate

Question 2

A technician is tasked with determining the bulk density (unit weight) of a coarse aggregate sample by rodding, in accordance with ASTM C29/C29M. The procedure involves placing the aggregate into a calibrated measure in how many approximately equal layers?

Accepted Answer

Three layers

Answer

One continuous layer

Answer

Two layers

Answer

Four layers

Question 3

Which of the following properties is determined using the Los Angeles (L.A.) abrasion test (ASTM C131)?

Accepted Answer

The resistance of coarse aggregate to degradation by abrasion and impact

Answer

The percentage of voids in an aggregate sample

Answer

The amount of material finer than the 75-µm (No. 200) sieve

Answer

The absorption capacity of fine aggregate

Question 4

A laboratory is testing a coarse aggregate sample for specific gravity and absorption according to ASTM C127. The aggregate is soaked for a prescribed period and then dried to a saturated-surface-dry (SSD) condition. What does the SSD condition signify?

Accepted Answer

The aggregate's permeable pores are filled with water, but the surfaces of the particles are dry.

Answer

The aggregate has been oven-dried to a constant mass.

Answer

The aggregate is completely submerged in water.

Answer

The aggregate contains no moisture in its pores or on its surface.

Question 5

When an accurate determination of the material finer than the 75-µm (No. 200) sieve is required for an aggregate sample, ASTM C136 states that dry sieving alone is insufficient. Which test method should be performed prior to the dry sieve analysis?

Accepted Answer

ASTM C117 (Materials Finer than 75-µm Sieve by Washing)

Answer

ASTM C29 (Unit Weight)

Answer

ASTM C127 (Specific Gravity and Absorption of Coarse Aggregate)

Answer

ASTM C131 (L.A. Abrasion)

Question 6

A technician performing a bulk density test on a dry coarse aggregate sample according to ASTM C29 obtains the mass of the aggregate in the measure and knows the volume of the measure. To calculate the voids in the aggregate, what additional property of the aggregate must be known?

Accepted Answer

The bulk specific gravity (dry basis) of the aggregate

Answer

The absorption of the aggregate

Answer

The L.A. abrasion loss value

Answer

The fineness modulus of the aggregate