CCIL Concrete Field Testing Procedures 5

Question 1

When using a penetration resistance apparatus per ASTM C403, what does a penetration resistance of 500 psi (3.5 MPa) indicate?

Accepted Answer

Initial set of concrete

Answer

Per ASTM C403, initial set is defined as the time required to reach a penetration resistance of 500 psi (3.5 MPa).

Question 2

According to ASTM C172, what portion of a truck load must be excluded when sampling fresh concrete?

Accepted Answer

First and last 10%

Answer

ASTM C172 requires that samples be taken after discarding the first and last 10% of the batch to ensure a representative sample.

Question 3

What is the acceptable temperature range for fresh concrete at the time of delivery per most North American specifications?

Accepted Answer

7°C to 32°C (45°F to 90°F)

Answer

Many specifications and ACI 305/306 recommend concrete delivery temperatures between 7°C (45°F) and 32°C (90°F) to prevent cold- or hot-weather placement problems.

Question 4

Which test method is used to determine the time of setting of concrete mixtures by penetration resistance?

Accepted Answer

ASTM C403

Answer

ASTM C403 covers the test method for time of setting of concrete mixtures by penetration resistance on mortar sieved from the mix.

Question 5

When casting 100×200 mm (4×8 in.) concrete cylinders using rodding, how many times must each layer be rodded?

Accepted Answer

25 times

Answer

Per ASTM C31, each layer in a 100×200 mm cylinder is rodded 25 times uniformly distributed over the cross-section.

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL - Canadian Council of Independent Laboratories Practice Test

CCIL Concrete Field Testing Procedures 5