ACI Certification Strength Testing Technician 4

Question 1

Per ASTM E4, how often must the testing machine used for compressive strength tests be verified for force-measurement accuracy?

Accepted Answer

Every 12 months

Answer

Every 6 months

Answer

Every 18 months

Answer

Every 24 months

Question 2

Unbonded neoprene pad caps used as an alternative to sulfur mortar for compressive strength testing must conform to which ASTM standard?

Accepted Answer

ASTM C1231

Answer

ASTM C617

Answer

ASTM C192

Answer

ASTM C1064

Question 3

Per ASTM C1231, which Shore A durometer hardness neoprene pad is specified for testing concrete with a design compressive strength up to 7,000 psi (50 MPa)?

Accepted Answer

50 durometer

Answer

40 durometer

Answer

60 durometer

Answer

70 durometer

Question 4

Per ASTM C617, the maximum allowable thickness of a sulfur mortar cap on a test cylinder is:

Accepted Answer

3/16 inch (5 mm)

Answer

1/16 inch (1.6 mm)

Answer

1/8 inch (3 mm)

Answer

1/4 inch (6 mm)

Question 5

Which ASTM standard governs the flexural strength of concrete using a simple beam with third-point loading?

Accepted Answer

ASTM C78

Answer

ASTM C293

Answer

ASTM C496

Answer

ASTM C805

Question 6

A compressive testing machine must be accurate to within what percentage of the indicated load throughout the range being used, per ASTM E4?

Accepted Answer

± 1.0%

Answer

± 0.5%

Answer

± 2.0%

Answer

± 5.0%

Question 7

When sampling fresh concrete from a truck mixer per ASTM C172, a composite sample must be obtained from at least how many regularly spaced portions of the discharge?

Accepted Answer

Two or more portions throughout the middle of discharge

Answer

One portion taken at mid-discharge

Answer

Three or more portions at equal intervals

Answer

Five or more portions across the full discharge