ACI - Concrete Field Testing Technician Grade I

All workbook questions and couple extra that I believe are important to know.

C1064 Temperature - According to ASTM C1064, composite samples are required even if the only purpose for obtaining the sample is to determine temperature.

False

C1064 Temperature - Temperature measurement of freshly mix concrete must be completed within _ after obtaining the sample.

5 Minutes

C172 Sampling - How many revolutions minimum must the truck have before sampling?

30 mixing revolutions

C172 Sampling - How long must you wait before testing if you sampled from a Continuous Mixer?

Minimum 2 minutes, no more than 5 minutes. To allow hydration of the cement to begin.

C172 Sampling - For Slump, Maximum Aggregate and Wet Sieve Size?

1 ½ inches, 1 ½ inches

C172 Sampling - For Air Content (Pressure), Maximum Aggregate and Wet Sieve Size?

2 inches ,1 ½ inches

C172 Sampling - For Air Content (Roll-A-Meter), Maximum Aggregate and Wet Sieve Size?

1 ½ inches, 1 inch

C172 Sampling - For Cylinders 6 × 12, Maximum Aggregate and Wet Sieve Size?

2 Inches, 2 Inches

C172 Sampling - For Cylinders 4 × 8, Maximum Aggregate Size and Wet Sieve Size?

1 ¼ inches, N/A

C172 Sampling - This practice covers sampling from four types of equipment, which are?

Stationary Mixer, Revolving Truck Mixer, Continuous Mixer, Paving Mixer.

C172 Sampling - The elapsed time between obtaining the first and final portions of a composite sample shall not exceed _?

15 Minutes

C172 Sampling - Portions of a composite sample shall be thoroughly remixed before beginning tests on the sample. True or False?

True

C172 Sampling - Start tests for slump, temperature, and air content within _ after obtaining the final portion of the composite sample.

5 Minutes

C172 Sampling - Start molding specimens for strength tests within _ after fabricating the composite sample.

15 Minutes

C172 Sampling - The concrete sample must be protected from contamination and _

Evaporation

C172 Sampling - The minimum size sample for making strength test specimens is _

1ft³

C172 Sampling - When sampling from a stationary mixer, the batch must be sampled at _ or more regularly spaced intervals during discharge of the middle portion of the batch.

2

C172 Sampling - When sampling from a paving mixer, obtain samples from at least _ different portions of the pile and combine them into one composite sample for test purposes.

5

C172 Sampling - When sampling from a revolving truck mixer, sample the concrete by collecting _ or more portions take at regularly spaced intervals during discharge of the middle portion of the batch.

2

C172 Sampling - Concrete samples from a truck mixer must be obtained before any water or admixtures are added to the mixer at the job site. True or False?

False

C172 Sampling - When the concrete contains aggregate larger than that permitted for a particular test method, the sample of concrete must be _ before making the test.

Wet Sieved

C172 Sampling - To obtain a representative sample from revolving drum truck mixer, regulate the rate of discharge by:

Adjusting the rate of the revolution of the drum.

C1064 Temperature - For aggregate up to and including 1 in., container must provide how much cover around the end of temperature sensor?

3 in.

C1064 Temperature - For aggregate over 1 in. how much cover must the container provide?

Cover of at least 3 times the nominal maximum size.

C1064 Temperature - If aggregate is larger than 3 inches how much time is allowed for the reading to stabilize?

Up to 20 minutes

C1064 Temperature - The stem of the thermometer is submerged a minimum of _ into the freshly mixed concrete.

3 inches.

C1064 Temperature - The thermometer shall be capable of accurately measuring the temperature of freshly mixed concrete to _ throughout a range of _?

1 F, 30 F - 120 F

C1064 Temperature - The thermometer shall be verified within _.

Annually

C1064 Temperature - The temperature of concrete may be measured in a wheelbarrow. True or False?

True

C1064 Temperature - The temperature of concrete may be measured in a wall form. True or False?

True

C1064 Temperature - A composite sample of concrete is required even if the only purpose for obtaining the sample is to determine temperature. True or False?

False

C1064 Temperature - What must be done to the sample container prior to sampling the concrete?

Dampen with water

C1064 Temperature - What must be done to the concrete surrounding the thermometer after the device is submerged in the fresh concrete?

Push concrete around the stem to ensure the concrete is in full contact with the stem.

C1064 Temperature - How long must the thermometer remain in the freshly mixed concrete?

Between 2 - 5 minutes

C1064 Temperature - After the temperature of the concrete is read, what is then required?

Record the temperature.

C1064 Temperature - The temperature of the concrete is recorded to the nearest _.

1 F

C1064 Temperature - There is specified maximum temperature of freshly mixed concrete. True or False?

False

C1064 Temperature - The sample of concrete used for temperature determination must be rodded 25 times. True or False?

False

C143 Slump - When the concrete contains aggregate larger than allowed for the slump test, the large aggregate must be_.

Wet Sieved over 1 ½

C143 Slump - The mold for making the slump test is in the shape of _

The frustrum of a cone

C143 Slump - The height of the slump mold is _.

12 Inches

C143 Slump - The interior surface of the slump mold is allowed to have minor irregularities. True or False?

False

C143 Slump - For use in the slump test, the tamping end or both ends of the tamping rod must be_.

Rounded to a hemispherical tip.

C143 Slump - The slump mold should be in a dry condition before beginning the test. True or False?

False

C143 Slump - The surface on which the slump mold will be placed must be _.

Flat, Level, Damp, Nonabsorbent, and Rigid

C143 Slump - The slump mold is filled in _ layers.

3

C143 Slump - Each layer should fill approximately _ the volume of the mold

one-third

C143 Slump - Rod each layer _ times uniformly over the cross section with the rounded end of the rod.

25

C143 Slump - How deep should the tamping rod penetrate into each layer?

Throughout its depth and penetrate previous layer by approximately 1 inch.

C143 Slump - What must be done if the concrete drops below the top of the slump mold while the top layer is being rodded?

Add additional concrete to keep an excess amount of concrete above the mold.

C143 Slump - Prior to lifting the mold, concrete must be removed from _.

The area surrounding the base of the mold.

C143 Slump - After the final rodding, the sides of the slump mold should be tapped lightly with the tamping rod. True or False?

False

C143 Slump - When raising the slump mold, it should not be rotated or twisted. True or False?

True

C143 Slump - How much time is allowed for lifting the slump mold?

5 ± 2 seconds

C143 Slump -The measurement for slump is made from the top of the mold to what point of the concrete specimen?

To the displaced original center of the top

C143 Slump - The slump of the concrete is measure and reported to the nearest _.

Nearest ¼ inch

C143 Slump - How much time is allowed to conduct the slump test from beginning to complete?

2 ½ minutes

C143 Slump - What is required size of the tamping rod?

5/8 inches in diameter and 16-24 inches in length.

C143 Slump - When performing a slump test a concrete sample with 2in maximum size aggregate requires what?

Removal of aggregate over 1 ½ inch by wet sieving on a 1 ½ inch sieve.

C143 Slump - Slump test is not applicable to?

Non-plastic and non-cohesive concrete.

C143 Slump - If a slump cone mold made of material other than metal is suspected of being out of tolerance. What must be done and what would determine it to be removed from service?

Compare it to a metal slump cone and if the results differ by more than 0.5in

C138 Unit Weight - The length of the tamping rod used in this method is_

4 inches taller than height of measure but no more than 24 inches.

C138 Unit Weight - What is the required shape of the tamping end of the rod?

Rounded to a hemispherical tip

C138 Unit Weight - What is the required minimum frequency of the vibrator used in this test method?

9000 vibrations per minute

C138 Unit Weight - The outside diameter or side dimension of the vibration element must be at least _ but not greater than _.

0.75 inches, 1.5 inches

C138 Unit Weight - What material is the measure made of?

Typically metal

C138 Unit Weight - What is the minimum thickness of a metal strike-off plate?

¼ inch

C138 Unit Weight - What is the minimum thickness for a glass or acrylic strike-off plate?

½ inch

C138 Unit Weight - What is the specified weight of the mallet used on measures that are 1/2ft³ or smaller?

1 ¼ ± ½ lb

C138 Unit Weight - What method of consolidation must be used when the slump is greater than 3in?

Rodding

C138 Unit Weight - What method of consolidation must be used when the slump is less than 1in?

Vibration

C138 Unit Weight - If rodding is the method of consolidation being used, the measure must be filled in how many layers?

3 layers

C138 Unit Weight - For a measure of ½ ft³, what is the require number of strokes of the tamping rod for consolidation of each layer?

25

C138 Unit Weight - When rodding the middle and top layers, the tamping rod should penetrate into the layer below approximately_

1 inch

C138 Unit Weight - If vibration is the method of consolidation, the measure must be filled in _ approximately equal layers

2

C138 Unit Weight - If, after consolidation of the final layer, the concrete level is ½ in above the top of the measure, should be done?

Remove enough to have only approximately 1/8 inch above the top

C138 Unit Weight - After completing the strike-off procedure, what must be done before weighing the measure and sample?

Clean any excess concrete

C138 Unit Weight - Yield is defined as the?

Volume of concrete produced from a mixture of known quantities of component materials

C138 Unit Weight - The minimum capacity of a “Unit Weight” measure is based on the

Nominal maximum size of coarse aggregate in the concrete.

C138 Unit Weight - When 3 1/2 slump concrete is consolidated in a 0.5 cubic foot measure, consolidation is accomplished by?

Rodding

C138 Unit Weight - What method of consolidation must be used when the slump is in 1in. to 3 in.?

Either Rodding or Vibration

C138 Unit Weight - For measures greater than ½ ft³ what must the mallet weigh?

2 ¼ ± ½ lb

C138 Unit Weight - Minimum volume the measure must be?

0.2 ft³

C138 Unit Weight - How much wider than the opening must the strike-off plate of either material be?

1 in. wider

C231 Air Content (Pressure) - The pressure method of determining air content can be used on concrete containing _ and _ aggregate.

Normal Weight, heavyweight

C231 Air Content (Pressure) - The pressure method of determining air content cannot be used on concrete containing the following: _ or _

Lightweight aggregates, aggregates of high porosity

C231 Air Content (Pressure) - What is the specified size of the mallet required for a typical air meter?

1 ¼ ± ½ lb

C231 Air Content (Pressure) - Wet screening may be necessary when the mixture contains aggregate with a nominal maximum size greater than _

1 ½ in.

C231 Air Content (Pressure) - If the concrete sample is to be consolidated by rodding, the measure is filled in _ layers.

3

C231 Air Content (Pressure) - If the concrete sample is to be consolidated by vibration, the measure is filled in _ layers.

2

C231 Air Content (Pressure) - When rodding the concrete sample, what is the specified number of strokes required for each layer?

25

C231 Air Content (Pressure) - Vibration of the concrete sample is not allowed when the slump of the concrete exceeds _

3 in.

C231 Air Content (Pressure) - In rodding the sample, how deep should the rod penetrate each layer?

Approximately 1 in.

C231 Air Content (Pressure) - After rodding each layer, what should be done to the measure before adding another layer of concrete?

Hit sides with mallet 10-15 times

C231 Air Content (Pressure) - What tools may be used to strike off the top surface of the concrete following consolidation of the final layer?

Strike-off bar or Strike-off plate.

C231 Air Content (Pressure) - According to ASTM C231, vibrating longer than necessary to properly consolidate the sample can cause what?

May cause segregation and loss of intentionally entrained air.

C231 Air Content (Volumetric) - The volumetric method of determining air content of concrete can be used on concrete containing what types of aggregate?

All types of aggregate

C231 Air Content (Volumetric) - What are the requirements for the tamping rod used in this test method?

Steel or plastic must be no more than 24 inches, but 4 inches taller than the height of the measure. 5/8” diameter and a hemispherical tip

C231 Air Content (Volumetric) - What are the requirements for the strike-off bar used in this test method?

Metal or plastic. 3/4” width, 12” length. At least 1/8” thickness if metal and 1/4” if plastic

C231 Air Content (Volumetric) - What is the minimum capacity of the measuring cup used to add alcohol to the air meter?

1 pint