ACI Certification Strength Testing Technician 5

Question 1

A concrete cylinder intended for compressive strength testing was inadvertently allowed to surface-dry before testing. What must be done per ASTM C39?

Accepted Answer

Re-wet the specimen and allow it to re-soak before testing

Answer

ASTM C39 requires specimens to be in a moist condition at the time of testing; if dried, they must be re-wetted and allowed to soak to restore proper moisture.

Question 2

Which piece of information is NOT typically required on a concrete cylinder identification tag used in the field?

Accepted Answer

Exact mix design proportions by weight

Answer

Exact mix design proportions are on the batch ticket, not the cylinder tag; date/time, load ID, and placement location are the standard tag requirements.

Question 3

Per ASTM C31, after the initial curing period, standard-cured specimens must be stored in water or a moist room at what specified nominal temperature?

Accepted Answer

73°F (23°C)

Answer

Standard curing per ASTM C31 requires specimens to be maintained at 73 ± 3°F (23 ± 2°C) in water or a moist room after the initial field cure.

Question 4

What is the primary purpose of making both field-cured and standard-cured cylinders from the same concrete placement?

Accepted Answer

To evaluate the adequacy of curing and protection applied in the field

Answer

Comparing field-cured to standard-cured cylinders reveals whether field curing and protection are achieving adequate in-place concrete strength.

Question 5

Per ASTM C617, how long must a sulfur mortar cap be allowed to harden before the capped cylinder can be tested?

Accepted Answer

2 hours

Answer

ASTM C617 requires that sulfur mortar caps be allowed to harden for a minimum of 2 hours before a load is applied to the specimen.

ACI (American Concrete Institute Certification) Practice Test

ACI (American Concrete Institute Certification) Practice Test

ACI Certification Strength Testing Technician 5