Question 1

Which of the following conditions must be met for test results from trial mixes of low cement castables to be accepted for qualification?

Options :

A : The water content must not vary more than ±1.0% from that recommended by the manufacturer.

B : Specimens must be fired at 1500°F (815°C) and held for a minimum of 3 hours.

C : Bulk density and CCS must exceed average values published in ASTM C401.

D : The drying process must be conducted at 220°F (104°C) for at least 48 hours before firing.

Answer: A

Question 2

Which of the following is a correct condition for gunned material test panels used for CCS and PLC testing?

Options :

A : Test panels must be 24 in. Ã— 24 in. Ã— 6 in. thick and shot vertically.

B : The minimum gunned thickness shall be 2 in., with a tolerance of ±0.25 in.

C : A vibrating screed must be used during panel finishing.

D : Test panels must be dried at 400°F (204°C) for 6 hours before specimen extraction.

Answer: B

Question 3

When is metal fiber reinforcement used in castable refractory?

Options :

A : Only when extra strength is required

B : Only when added in the field

C : For all monolithic hot face castable refractory materials

D : Only when specified by the owner

Answer: D

Question 4

To compose a sample for CCS test from an equivalent number of refractory shapes the specimen should be

Options :

A : at least five

B : at least three

C : at least four

D : None of the above

Answer: A

Question 5

The application of monolithic refractories by means of air placement guns is

Options :

A : gunning

B : placing

C : pouring

D : casting

Answer: A

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