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ASTM C1064 ANSWER- Standard Test Method For Temperature of Freshly Mixed Hydraulic-Cement Concrete The sensor of the temperature measuring device shall be submerged a minimum of inches into the freshly mixed concrete. ANSWER - 3" The temperature measuring device shall have a capacity of measuring temperature of freshly mixed concrete to ± °F throughout a range of. ANSWER- 1 degree, 30 degrees to 120 degrees The temperature measuring device shall be calibrated , or whenever there is a question of
. ANSWER- Annually, accuracy The temperature of concrete may be measured in a wheelbarrow. True or False? ANSWER - True The temperature of concrete may be measured in a wall form. True or False? ANSWER- True What must be done to the sample container prior to sampling the concrete? ANSWER- Dampen with water What must be done to the concrete surrounding the temperature measuring device after the device is submerged in the fresh concrete? ANSWER - Close off air voids by gently pressing the concrete around the device
How long must the temperature measuring device remain in the freshly mixed concrete? ANSWER- minimum of two minutes, maximum of five minutes The temperature of the concrete is reported to the nearest °F ANSWER - 1 degree A maximum temperature of freshly mixed concrete is specified in ASTM C1064. True or False? ANSWER - False ASTM C172 ANSWER- Standard Practice for Sampling Freshly Mixed Concrete Sampling by this method is required when tests are to be made to determine with specification requirements. ANSWER - Compliance This method covers sampling from four types of mixers, which are , , , and. ANSWER- Stationary mixers, paving mixers, revolving drum mixers and open top mixers The maximum allowable time between obtaining the first and final portions of a composite sample is minutes. ANSWER - 15 Portions of a composite sample shall be thoroughly remixed before beginning tests on the sample. True or False? ANSWER - True The maximum elapsed time allowed between obtaining the final portion of the composite sample and beginning the tests for slump, temperature, and air content is minutes. ANSWER - 5 The molding of strength test specimens shall begin within minutes after fabricating the composite sample. ANSWER - 15
pass a receptacle through the entire discharge stream, Completely divert the discharge stream into a sample container What are the required steps for collecting a sample of concrete from a stationary or revolving drum mixer? (Oral Exam) ANSWER- Collect two or more portions of concrete, Take the portions at regularly spaced intervals, Take the portions from the middle of the batch Describe the procedure for collecting a sample of pavement concrete deposited on grade. (Oral Exam) ANSWER- Discharge the contents of the paving mixer, Obtain samples from at least five different portions of the pile What is the minimum size for a sample when strength test specimens are to be molded? (Oral Exam) ANSWER- 1 cubic foot (28 L) What is the maximum allowable time between obtaining the first and final portions of the composite sample? (Oral Exam) ANSWER- 15 min. What is required after the concrete sample has been transported to the place where tests are to be performed? (Oral Exam) ANSWER- Combine and remix the sample with a shovel What should be done if the concrete contains aggregate larger than is appropriate for the size of the molds or equipment being used? (Oral Exam) ANSWER- Wet sieving Start the tests for slump, temperature, and air content within how many minutes after obtaining the final portion of the composite sample? (Oral Exam) ANSWER- 5 min. Start molding specimens for strength tests within how many minutes after fabricating the composite sample? (Oral Exam) ANSWER- 15 min. From what must the concrete sample be protected? (Oral Exam) ANSWER- Sun, wind, rapid evaporation, and contamination
ASTM C143 ANSWER- Standard Test Method for Slump of Hydraulic-Cement Concrete The slump test is applicable to plastic concrete with a maximum size aggregate of. ANSWER- 1½ in. When the concrete contains aggregate larger than allowed for the slump test, the large aggregate must be. ANSWER- Removed by wet sieving the sample over 1½ in. sieve The mold for making the slump test is in the shape of. ANSWER- The frustum of a cone The height of the slump mold is. ANSWER- 12 in. The interior surface of the slump mold is allowed to have minor irregularities. True or False? ANSWER
- False For use in the slump test, the end or both ends of the tamping rod must be . ANSWER- Rounded to a hemispherical tip The sample of concrete for use in making the slump test must be obtained in accordance with ASTM Standard. ANSWER- C172, Standard Practice for Sampling Freshly Mixed Concrete The slump mold should be in a dry condition before beginning the test. True or False? ANSWER- False The surface on which the slump mold will be placed must be. ANSWER- Flat, level, moist, nonabsorbent, and free of vibration
The measurement for slump is made from the top of the mold to what point of the concrete specimen? ANSWER- The displaced original center of the top surface of the specimen The slump of the concrete is measured and reported to the nearest. ANSWER- ¼ in. [5 mm] How much time is allowed to conduct the slump test from beginning to completion? ANSWER- 2½ minutes ASTM C138 ANSWER- Standard Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete The diameter of the tamping rod used in this test method is. ANSWER- ⅝ in. [16 mm] What is the required shape of the tamping end of the rod? ANSWER- Rounded to a hemispherical tip What is the required minimum frequency of the vibrator used in this test method? ANSWER- 7000 vibrations per minute The outside diameter or side dimension of the vibrating element must be at least but not greater than. ANSWER- 0.75 in. [19 mm], 1.50 in. [38 mm] A plastic container can be used for the measure in this method. True or False? ANSWER- False, measure must be steel or other suitable metal What is the minimum thickness of a metal strike-off plate? ANSWER- ¼ in. [6 mm]
What is the minimum thickness for a glass or acrylic strike-off plate? ANSWER- ½ in. [12 mm] What is the specified weight of the mallet used on measures that are 0.5 ft3 [ L] or smaller? ANSWER- 1.25 ± 0.50 lb. [600 ± 200 g] Measures other than air meter bowls used for this test must conform to ASTM. ANSWER- C Air meter bowls used for this test must conform to ASTM and be calibrated for volume according to ASTM. ANSWER- C231, C The concrete sample must be obtained in accordance with what ASTM method? ANSWER- C What method of consolidation must be used when the slump is greater than 3 in. [75 mm]? ANSWER
- Rodding What method of consolidation must be used when the slump is less than 1 in. [ mm]? ANSWER- Vibration If rodding is the method of consolidation being used, the measure must be filled in how many layers? ANSWER- 3
a) The yield per batch in ft b) The yield per batch in yd c) The yield in m d) The yield per cubic yard in ft3/yd3 ANSWER- a. Yield per batch = 189.7 ft b. Yield per batch = 7.0 yd c. Yield per batch = 5.4 m d. Yield per cubic yard = 27.1 ft3/yd Relative Yield Calculation Using the information given and calculated in Question 22, calculate the relative yield for the batch of concrete. ANSWER- 1. Air Content Calculation Your air meter has been damaged in transit to the job site. You do, however, possess the theoretical density that was determined in the lab; it is 151.4 lb/ft (2425 kg/m3). Using the density calculated in Question 21, calculate the air content of the batch (in percentage). ANSWER- 5.0% = [(151.4 lb/ft3 - 143.9 lb/ft3) / 151.4 lb/ft3] × 100 5.0% = [(2425 kg/m3 - 2305 kg/m3) / 2425 kg/m3] × 100 ASTM C231 ANSWER- StandardTestMethodforAirContentofFreshlyMixedConcretebythePressureMethod The pressure method of determining air content can be used on concrete containing aggregate. ANSWER- Relatively Dense The pressure method of determining air content cannot be used on concrete containing the following types of aggregate: , ,. ANSWER- Lightweight, air-cooled blast furnace slag, or aggregates of high porosity What is the minimum allowable capacity of the measuring bowl used in this test
method? ANSWER- 6 L (0.20 ft3) What are the required characteristics of the tamping rod used in this test method? 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 [ in.] in overall length, with the tamping end rounded to a hemispherical tip of the same diameter as the rod. What is the specified size of the mallet required for this test method when the measuring bowl has a capacity of 14 L [0.5 ft3] or less? ANSWER- 0.60 ± 0.25 kg [1.25 ± 0.50 lb.] The sample of concrete used for this test is to be obtained in accordance with what ASTM Standard? ANSWER- C The maximum size aggregate allowed for this test method is. ANSWER- 50 mm (2 in.) If the concrete contains aggregate larger than the maximum allowed for this test, the sample must be
. ANSWER- Wet sieved over a 1½ in. (37.5 mm) sieve If the concrete sample is to be consolidated by rodding, the measure is filled in layers. ANSWER
- 3 equal If the concrete sample is to be consolidated by vibration, the measure is filled in layer s. ANSWER- 2 equal When rodding the concrete sample, what is the specified number of strokes
What are the requirements for the tamping rod used in this test method? ANSWER- Round, straight 5/8 [16 mm] ± 1/16 in.[2 mm] diameter rod at least 4 in. [300 mm] greater in length than the depth of the bowl being used, with the tamping end rounded to a hemispherical tip of the same diameter, made of steel, high-density polyethylene, or other plastic of equal or greater abrasion resistance. What are the requirements for the strike-off bar used in this test method? ANSWER- Flat, straight steel bar at least 1/8 by 3/4 by 12 in. [3 by 20 by 300 mm] or a flat, straight high-density polyethylene bar, or other plastic of equal or greater abrasion resistance, at least 1/4 by 3/4 by 12 in. [6 by 20 by 300 mm]. What is the approximate volume of the measuring cup used to add water to the air meter, in relation to the volume of the air meter bowl? ANSWER- 1.00% ± 0.04% What type of alcohol and concentration must be used in this test method? ANSWER- Isopropyl, 70% by volume (65% by weight) A mallet weighing must be used to tap the sides of the bowl after rodding each layer. ANSWER
- 1.25 ± 0.50 lb. (600 ± 200 g) The sample of concrete used in this test method must be obtained in accordance with what ASTM Standard? ANSWER- C The maximum size aggregate allowed in this test method is. ANSWER- 1½ in. (37.5 mm) If the concrete sample contains aggregate larger than that allowed for this test, the sample must be . ANSWER- Wet sieved over a 1 - in. (25-mm) sieve When filling the measuring bowl of the air meter, the concrete must be placed in layers of
equal depth. ANSWER- 2 What is the specified number of strokes required when rodding each layer of concrete? ANSWER- 25 It is necessary to tap the sides of the measuring bowl after each layer has been rodded. True or False? ANSWER- True The initial quantity of water and alcohol added to the air meter can be poured directly into the neck of the top section of the air meter. True or False? ANSWER- False; the funnel must be used Upon final filling of the air meter with water, what part of the liquid level should be adjusted to the zero mark on the meter? ANSWER- Bottom of the meniscus How long should the air meter be inverted and agitated? 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 How many times does the rolling operation occur? ANSWER- A minimum of 2, a maximum of 3
ANSWER- The test is invalid ASTM C31 ANSWER- Standard Practice for Making and Curing Concrete Test Specimens in the Field ASTM Method C31 gives standardized requirements for , , , and , of test specimens. ANSWER- Making, curing, protecting, transporting For cylinders with a diameter of 6 in. [150 mm] or greater, the tamping rod must be a round, straight steel rod with a diameter of. ANSWER- 5/8 ± 1/16 in. [16 mm ± 2 mm] The minimum frequency of an internal vibrator used in this procedure is. ANSWER- 9000 vibrations per minute [150 Hz] The container for obtaining the concrete sample used in this procedure can be a , , or
. ANSWER- Metal pan, wheelbarrow, flat, clean nonabsorbent mixing board A 6 by 12 in. [150 mm by 300 mm] cylinder mold can be used for concrete containing aggregate with particles not exceeding in size, without the need for wet sieving the concrete. ANSWER- 2 in. [50 mm] The sample of concrete used in molding test specimens must be obtained in accordance with what ASTM Standard? ANSWER- C When strength specimens are to be made, what three other tests must be made? ANSWER- Slump, air content, temperature After molding test specimens, you should wait two hours before moving them to the location of initial storage. True or False? ANSWER- False; the specimens must be moved immediately
The supporting surface on which specimens are stored shall be level within
. ANSWER- 1/ in. per ft. [20 mm per m] For concrete with a slump of less than 1 in. [25 mm], the test specimens must be consolidated by. ANSWER- Vibration If the concrete is to be consolidated by vibration, a standard 4 by 8 in. [ mm by 200 mm] cylinder mold must be filled in equal layers. ANSWER- 2 When rodding a standard 6 by 12 in. [150 mm by 300 mm] cylinder, each layer must be rodded times. ANSWER- 25 When rodding each upper layer of concrete in a cylinder, the tamping rod should penetrate into the underlying layer by about. ANSWER- 1 in. [ mm] When using an internal vibrator to consolidate a 6 by 12 in. [150 mm by 300 mm] compressive strength test specimen, the vibrator must be inserted at different points for each layer. ANSWER- 2 When consolidating a flexural strength test specimen by rodding, rod one stroke for each of top surface area. ANSWER- 2 square inches When internal vibration is used to consolidate a standard flexural strength test specimen, the technician should insert the vibrator at intervals not exceeding along the center line of the beam. ANSWER- 6 in. [150 mm] Concrete mixtures with specified strengths of 6000 psi [40 MPa] or greater
The temperature and moisture environment for field cured cylinders must be . ANSWER- The same as the structural work Cylinders made for the purpose of determining when a structure may be put into service shall be removed from the molds. ANSWER- At the time of the removal of formwork
