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

ASTM E4 requires testing machines to be verified at least every 12 months and whenever there is reason to question their accuracy.

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 C1231 governs the use of unbonded neoprene pads in retaining rings as an alternative to sulfur mortar caps for testing concrete cylinders.

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

ASTM C1231 specifies 50 durometer neoprene pads for concrete with design strengths from 1,500 to 7,000 psi (10 to 50 MPa).

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

ASTM C617 requires caps to be as thin as practicable and not exceed 3/16 inch (5 mm) in thickness.

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 C78 covers the determination of flexural strength (modulus of rupture) using a simple beam with third-point loading.

ACI (American Concrete Institute Certification) Practice Test

ACI (American Concrete Institute Certification) Practice Test

ACI Certification Strength Testing Technician 4