CCIL - Canadian Council of Independent Laboratories Sample Management and Preparation Questions and Answers

Question 1

A field technician must obtain a representative sample from a large, conical stockpile of coarse aggregate.
According to CSA A23.2-1A, which of the following methods is the most appropriate to minimize the effects of segregation?

Accepted Answer

Combining at least three increments taken from the top, middle, and bottom thirds of the stockpile.

Answer

Taking a single, large scoop from the base of the pile at the point of truck loading.

Answer

Skimming a shallow layer of material from the entire sloped surface of the pile.

Answer

Using a front-end loader to take one bucketful from the working face of the pile.

Question 2

According to standard practices such as AASHTO T 248, what is the primary purpose of the quartering method when handling a large field sample of aggregate?

Accepted Answer

To obtain a smaller, representative specimen that has approximately the same composition as the original large sample.

Answer

To quickly remove any oversized or deleterious particles from the sample before testing.

Answer

To increase the density of the aggregate sample to match in-place conditions.

Answer

To separate the fine and coarse portions of the sample for individual analysis.

Question 3

Which of the following is a critical requirement for the *initial curing* of newly molded concrete test cylinders in the field as per CSA A23.2-3C, before they are transported to the laboratory?

Accepted Answer

Cylinders must be stored in a manner that prevents moisture loss and maintains a temperature between 15°C and 25°C.

Answer

Cylinders must be fully submerged in lime-saturated water within one hour of molding.

Answer

Cylinders must be stored in a dry, heated environment (above 30°C) to accelerate initial strength gain.

Answer

Cylinders must be left completely undisturbed and exposed to ambient site conditions for the first 24 hours.

Question 4

A technician receives a bulk sample of loose hot-mix asphalt from a plant. According to standards for reducing sample size (e.g., AASHTO T 248), what is the mandatory first step before quartering or splitting the sample?

Accepted Answer

Thoroughly mix the entire sample on a clean, hard surface to ensure it is homogeneous.

Answer

Immediately compact a portion of the sample to preserve its in-place properties.

Answer

Sieve the sample to remove any oversized aggregate before proceeding.

Answer

Add a solvent to the mix to facilitate easier handling and division.

Question 5

In the context of a CCIL-certified laboratory, what is the primary purpose of maintaining a strict chain of custody for construction materials samples?

Accepted Answer

To provide a chronological and legally defensible record of sample possession, handling, and storage.

Answer

To help in scheduling the daily workload for laboratory technicians.

Answer

To ensure the sample is always handled by the most senior technician available.

Answer

To be used exclusively for billing purposes to track the number of samples from a specific client.

Question 6

A technician is preparing a fine aggregate sample for a sieve analysis (CSA A23.2-2A). The field sample is visibly moist. Which of the following preparation steps is essential for an accurate dry sieve analysis?

Accepted Answer

Drying the sample to a constant mass in an oven at a temperature of 110 ± 5 °C.

Answer

Washing the aggregate over a 75 µm sieve to remove surface dust before drying.

Answer

Adding a calculated amount of water to achieve a saturated surface-dry (SSD) condition.

Answer

Sieving the sample immediately to measure the gradation in its as-received moisture state.