Free ACI Field Testing Technician Questions and Answers 1

Question 1

The concrete sample that will be used for the slump test needs to be obtained in compliance with ASTM Standard _____.

Accepted Answer

C172, Standard Practice for Sampling Freshly Mixed Concrete

Answer

0.75 in. [19 mm], 1.50 in. [38 mm]

Answer

Removed by wet sieving the sample over 1.5 in. [37.5 mm] sieve

Answer

2 5/8 in. [70 mm], 6 1/8 in. [160 mm]

Question 2

Before starting any tests on a composite sample, certain portions of the sample must be fully blended. Is it True or False?

Accepted Answer

TRUE

Answer

FALSE

Question 3

Use one stroke for every _____ of top surface area when rodding a flexural strength test specimen.

Accepted Answer

2 in.^2 [14 cm^2]

Answer

1 in. [25 mm]

Answer

1/8 in. [3 mm]

Answer

6 in. [150 mm]

Question 4

Every layer ought to occupy around _____ of the mold's volume.

Accepted Answer

One-third

Answer

One-fourth

Answer

One-half

Answer

3 Equal

Question 5

Which consolidation technique needs to be applied when the slump is less than one inch? (25 mm)?

Accepted Answer

Vibration

Answer

9000 Vibrations Per Minute [150 Hz]

Answer

Rodding

Answer

Rapid Evaporation

Question 6

How far into each layer should the tamping rod be inserted?

Accepted Answer

Rod each layer throughout its depth; on the second and final layers, the rod should penetrate into the previous layer approximately 1 in. [25 mm]

Answer

Flat, straight steel bar at least 1/8 by 3/4 by 12 in. [3 by 20 by 300 mm] or a 4.4 flat, straight high-density polyethylene bar, or other plastic of equal or greater abrasion resistance, at least 1/4 by 3/4 by 23 in [6 by 30 by 300 mm].

Answer

Round, straight steel rod, with a 16 mm [5/8 in.] +- 2 mm [1/16 in.] diameter, length at least 100 mm [4 in.] greater than the depth of the measuring bowl, but not greater than 600 mm [24 in.] in overall length, with the tamping end rounded to a hemispherical tip of the same diameter as the rod.

Answer

No more than five seconds at a time, but must be repeated for a minimum of 45 seconds to free concrete from the base

Question 7

Should vibration be used to solidify the concrete, a typical 4 by 8 in. It is necessary to fill the [100 mm by 200 mm] cylinder mold in _____ equal layers.

Accepted Answer

2

Answer

C172

Answer

Wet sieved over a 1 1/2 in. (37.5 mm) sieve

Answer

Wet sieved over a 1-in. (25-mm) sieve

Question 8

Field-cured cylinders are kept __________ and safeguarded __________.

Accepted Answer

In or on the structure as near to the point of deposit of the concrete represented as possible; In as near as possible the same way as the formed work

Answer

False, if the air content is more than 9%, the number of calibrated cups of water introduced into the meter to bring the liquid level within the graduated range must be added

Answer

Rod each layer throughout its depth; on the second and final layers, the rod should penetrate into the previous layer approximately 1 in. [25 mm]

Answer

Acceptance testing for specified strength, checking the adequacy of mixture proportions for strength, quality control

Question 9

After the last layer has been firmed up, what should be done if there is an excessive amount of concrete in the measurement?

Accepted Answer

Remove a representative quantity of concrete with the scoop or trowel before the strike off

Answer

C172, Standard Practice for Sampling Freshly Mixed Concrete

Answer

Add additional concrete to keep an excess of concrete above the top of the mold at all times

Answer

Lightweight, air-cooled blast furnace slag, or aggregates of high porosity

Question 10

What is the measuring bowl's minimum permitted volume that this test procedure uses?

Accepted Answer

6 L (0.20 ft^3)

Answer

28 l (1ft^3)

Answer

50 Mm (2 in.)

Answer

1/2 In. [12 mm]