CCIL - Canadian Council of Independent Laboratories Concrete Field Testing Procedures Questions and Answers

Question 1

According to CSA A23.2-5C, when performing a slump test, how should the slump cone be lifted from the concrete sample?

Accepted Answer

Vertically, in a smooth and continuous motion taking approximately 5 seconds

Answer

Quickly and with a twisting motion to break the bond

Answer

Slowly at first, then quickly after the first few centimeters

Answer

By tilting it to one side to allow air to enter before lifting

Question 2

A field technician is preparing to measure the air content of a fresh concrete sample using the pressure method (CSA A23.2-4C). The concrete has a specified slump of 30 mm. How should the concrete be consolidated in the measuring bowl?

Accepted Answer

By using an internal vibrator

Answer

By rodding each of the three layers 25 times

Answer

By tapping the sides of the bowl 50 times for each layer

Answer

By rodding the first layer and vibrating the top two layers

Question 3

As per CSA A23.2-1C, a representative sample of concrete for testing must be obtained from which portion of the ready-mix truck's discharge?

Accepted Answer

Between the 10% and 90% points of discharge

Answer

From the first 10% of the discharged load

Answer

From the last 10% of the discharged load

Answer

From a combination of the first, middle, and last portions of the load

Question 4

A technician is casting 100 mm x 200 mm cylinders for compressive strength testing from a concrete mix with a slump of 80 mm. Which of the following correctly describes the rodding procedure according to CSA A23.2-3C?

Accepted Answer

Fill the mold in 3 equal layers, rodding each layer 20 times with a 10 mm rod.

Answer

Fill the mold in 2 equal layers, rodding each layer 25 times with a 16 mm rod.

Answer

Fill the mold in 3 equal layers, rodding each layer 25 times with a 16 mm rod.

Answer

Fill the mold in 2 equal layers, rodding each layer 20 times with a 10 mm rod.

Question 5

When measuring the temperature of freshly mixed concrete according to CSA A23.2-17C, what is the minimum time the temperature measuring device must be left in the concrete?

Accepted Answer

A minimum of 2 minutes or until the reading stabilizes

Answer

30 seconds or until the reading is constant

Answer

Exactly 5 minutes after obtaining the sample

Answer

1 minute for every 100 mm of concrete depth

Question 6

During the performance of an air content test using the pressure method (Type B meter), after clamping the cover on the bowl and injecting water to expel the air, what is the next critical step before releasing the main air valve?

Accepted Answer

Pump air to the initial pressure line, stabilize it, and then close the petcocks

Answer

Strike the sides of the bowl sharply with a mallet

Answer

Invert the meter and shake it vigorously for 30 seconds

Answer

Open the main air valve immediately to get a quick reading