ACI CERTIFICATION - CONCRETE FIELD-TESTING TECHNICIAN GRADE 1

ACI CERTIFICATION - CONCRETE FIELD-TESTING TECHNICIAN GRADE 1 QUESTIONS WITH VERIFIED ANSWERS "Sampling Fresh Concrete: Portions of a composite sample shall be thoroughly remixed before beginning tests on the sample? True or False? - CORRECT ANSWER True (Reference 1.5.5)" "Sampling Fresh Concrete: Start tests for slump, temperature, and air content within ________________ after obtaining the final portion of the composite sample. - CORRECT ANSWER 5 minutes (Reference 1.5.5 & Figure 1.6)" "Sampling Fresh Concrete: Start molding specimens for strength tests within ___________________ after fabricating the composite sample. - CORRECT ANSWER 15 minutes (Reference 1.5.5 & Figure 1.6)" "Sampling Fresh Concrete: The concrete sample must be protected from contamination and ______________________. - CORRECT ANSWER Evaporation (Reference 1.2)" "Sampling Fresh Concrete: The minimum sample for making strength test specimens is _____________________. - CORRECT ANSWER 1 FT^3 (28 L) (Reference 1.5.1)" "Sampling Fresh Concrete: Where 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. - CORRECT ANSWER Two (Reference 1.5.2)" "Sampling Fresh Concrete: 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? - CORRECT ANSWER False (Reference 1.5.2)" "Sampling Fresh Concrete: When the concrete contains aggregate larger than that permitted for a particular test method, the sample of concrete must be ______________________ before making the test. - CORRECT ANSWER Wet screened (Reference 1.5.1)" "Temperature of Fresh Concrete: The stem of the thermometer is submerged a minimum of _______________________. - CORRECT ANSWER 3 inches (75 mm) (Reference 2.4)" "Temperature of Fresh Concrete: A composite sample of concrete is required even if the only purpose for obtaining the sample is to determine temperature. True or False? - CORRECT ANSWER False (Reference 2.3.3)" "Temperature of Fresh Concrete: What must be done to the sample container prior to sampling the concrete? - CORRECT ANSWER Dampened (with water) (Reference 2.3.3)" "Temperature of Fresh Concrete: There is a specified maximum temperature of freshly mixed concrete. True or False? - CORRECT ANSWER False" "Temperature of Fresh Concrete: The sample of concrete used for temperature determination must be rodded 25 times. True or False? - CORRECT ANSWER False" "Slump of Fresh Concrete: When the concrete contains aggregate larger than allowed for the slump test, the large aggregate must be _______________________________________________________________________________. - CORRECT ANSWER Wet screened over 1-1/2 in. (37.5 mm) sieve. ( Reference 3.5)" "Slump of Fresh Concrete: The mold for making the slump test is in the shape of __________________________________________________________________________________________________. - CORRECT ANSWER The frustrum of a cone. (Reference 3.5)" "Slump of Fresh Concrete: The height of the slump mold is _____________________. - CORRECT ANSWER 12 in. ( 300 mm) (Reference 3.5)" "Slump of Fresh Concrete: The interior surface of the slump mold is allowed to have minor irregularities. True or False? - CORRECT ANSWER False (Reference 3.5)" "Slump of Fresh Concrete: For use in the slump test, the tamping end or both ends of the tamping rod must be ____________________________________________________________. - CORRECT ANSWER Rounded to a hemispherical tip. (Reference 3.5)" "Slump of Fresh Concrete: Rod each layer _______________ times uniformly over the cross section with the rounded end of the rod. - CORRECT ANSWER 25 (Reference 3.5)" "Slump of Fresh Concrete: How deep should the tamping rod penetrate into each layer? - CORRECT 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). (Reference 3.5)" "Slump of Fresh Concrete: Prior to lifting the mold, concrete must be removed from _____________________________________________________________________________________________________. - CORRECT ANSWER The area surrounding the base of the mold (Reference 3.5)" "Slump of Fresh Concrete: After the final rodding, the sides of the slump mold should be tapped lightly with the tamping rod. True or False? - CORRECT ANSWER False (Reference 3.5)" "Slump of Fresh Concrete: When raising the slump mold, it should not be rotated or twisted. True or False? - CORRECT ANSWER True (Reference 3.5)" "Slump of Fresh Concrete: How much time is allowed for lifting the slump mold? - CORRECT ANSWER 5 +/- 2 seconds (Reference 3.5)" "Density (Unit Weight) and Yield of Fresh Concrete: The length of the tamping rod used in this test method is ___________________________________________________________________________________________________________________________________________________________________________________________________________________________. - CORRECT ANSWER At least 4 in. (100 mm) taller than the height of the measure but no more than 24 in. (600 mm) in overall length. (Reference 4.5.2)" "Density (Unit Weight) and Yield of Fresh Concrete: What material is the measure made of? - CORRECT ANSWER Typically metal (Reference 4.5.2)" "Density (Unit Weight) and Yield of Fresh Concrete: What is the minimum thickness of a metal strike-off plate? - CORRECT ANSWER 1/4 in. (6 mm) (Reference 4.5.2)" "Density (Unit Weight) and Yield of Fresh Concrete: What is the minimum thickness for a glass or acrylic strike-off plate? - CORRECT ANSWER 1/2 in. (12 mm) (Reference 4.5.2)" "Density (Unit Weight) and Yield of Fresh Concrete: For a measure of 1/2 ft^3 (14 L), what is the required number of strokes of the tamping rod for consolidation of each layer? - CORRECT ANSWER 25 (Reference 4.7.2.1)" "Density (Unit Weight) and Yield of Fresh Concrete: When rodding the middle and the top layers, the tamping rod should penetrate into the layer below approximately __________________________________. - CORRECT ANSWER 1 in. (25 mm) (Reference 4.7.2.1)" "Density (Unit Weight) and Yield of Fresh Concrete: If the vibration is the method of consolidation, the measure must be filled in ___________ approximately equal layers. - CORRECT ANSWER Two (Reference 4.7.2.2)" "Density (Unit Weight) and Yield of Fresh Concrete: If, after consolidation of the final layer, the concrete level is 1/2 in. (13 mm) above the top of the measure, what should be done? - CORRECT ANSWER Remove enough concrete to ensure you have overfilled the measure to approximately 1/8 in. (3 mm) above the top of the measure. (Reference 4.7.2)" "Density (Unit Weight) and Yield of Fresh Concrete: After completing the strike-off procedure, what must be done before weighing the measure and sample? - CORRECT ANSWER Clean off any excess concrete. (Reference 4.7.4)" "Density (Unit Weight) and Yield of Fresh Concrete: 17. Calculate the density of the concrete in lb/ft^3 (kg/m^3): Volume of measure = 0.504 ft^3 (0.01427 m^3) Mass of empty measure = 19.6 lb. (8.89 kg) Mass of the measure plus the concrete = 92.1 lb (41.78 kg) Calculate for both lb/ft^3 and kg/m^3. You'll need this information for future questions. - CORRECT ANSWER 143.8 llb/ft^3 and 2305 kg/m^3 (Reference 4.7.7) Density equals net mass of concrete divided by the volume of the measure. D = 72.5 lb / 0.504 ft^3) = 143.849 (Round to tenth place) D = 32.89 kg/0.01427 m^3 = 2,304.84 (Round to whole number) Net mass of concrete: 92.1 lb (41.78 kg) - 19.6 lb (8.89 kg) = 72.5 (32.89 kg)" "Density (Unit Weight) and Yield of Fresh Concrete: Yield calculations: 18. The total mass of all material batched was 27,300 lb (12,383 kg). Using the density of the concrete as determined in Question 17, calculate: Density from Question 17 is 143.8 lb/ft^3 and 2,305 kg/m^3. A. Relative yield in ft^3 (M/D) = B. Relative yield in Yd^3 [M/(Dx27)] = C. Relative yield in m^3 (M/D) = - CORRECT ANSWER A. Yield = 189.8 ft^3 (Reference 4.7.8) M/D = 27,300 lb / 143.8 lb/ft^3 = 189.847 ft (Round to tenth place) B. Yield = 7.0 yd^3 M/(Dx27) = 27,300 lb / (27 x 143.8 lb/yd^3) = 27,300 / 3882.6 lb/yd^3 = 7.031 yd^3 (Round to tenth place) C. Yield = 5.4 m^3 M/D = 12,383 kg / 2305 kg/m^3 = 5.34 m^3 (Round to tenth place)" "Density (Unit Weight) and Yield of Fresh Concrete: 19. Relative Yield Calculation: The volume designed for the bath (Yd) was 7.0 yd^3 (5.4 m^3). Using the yield as determined in Question 18, calculate: Yield from Question 18 is 189.8 ft^3, 7.0 yd^3, and 5.4 m^3. A. Relative yield using ft^3 (Y/Yd) = B. Relative yield using yd^3 (Y/Yd) = C. Relative yield using m^3 (Y/Yd) = - CORRECT ANSWER 1.00 (Reference 4.7.8) A. Ry (Using ft^3) = Y/Yd = 189.8 ft^3 / (7.0 yd^3 x 27) = 189.8 ft^3 / 189 ft^3 = 1.00 B. Ry (Using yd^3) = Y/Yd = 7.0 yd^3 / 7 yd^3 = 1.00 C. Ry (Using m^3) = Y/Yd = 5.4 m^3 / 5.4 m^3 = 1.00" "Density (Unit Weight) and Yield of Fresh Concrete: Air Content Calculation: Your air meter has been damaged in transit to the job site. You do, however, know the theoretical density that was determined in the lab: 151.4 lb/ft^3 (2426 kg/m^3). Using the density of the concrete calculated in Question 17, calculate: Density from Question 17 is 143.8 lb/ft^3 and 2,305 kg/m^3. (Reference 4.7.9, page 50) A. Air content (in percentage) using density in lb/ft^3: B. Air content (in percentage) using density in kg/m^3: - CORRECT ANSWER 5.0% (Reference 4.7.9, page 50) A. Air Contention Using Density in lb/ft^3: [(151.4 lb/ft^3 - 143.8 lb/ft^3) / 151.4 lb/ft^3] x 100 = 5.0% B. Air Content Using Density in kg/m^3: [(2426 kg/m^3 - 2305 kg/m^3) x 2426 kg/m^3 x 100 = 5.0%" "Air Content of Fresh Concrete - Pressure Method: The pressure method of determining air content can be used on concrete containing ________________________ and __________________________ aggregate. - CORRECT ANSWER Normal weight; heavyweight (Reference 5.2)" "Air Content of Fresh Concrete - Pressure Method: The pressure method of determining air content cannot be used on concrete containing the following: _______________________________________________ or _______________________________________________________. - CORRECT ANSWER Lightweight aggregates; aggregates of high porosity (Reference 5.2)" "Air Content of Fresh Concrete - Pressure Method: Vibration of the concrete sample is not allowed when the slump of the concrete exceeds ___________________. - CORRECT ANSWER 3 in. (75 mm) (Reference 5.4.2)" "Air Content of Fresh Concrete - Pressure Method: In rodding the sample, how deep should the rod penetrate each layer? - CORRECT ANSWER Rod bottom layer through full depth; rod second and final layer penetrating the previous layer about 1 in. (25 mm). (Reference 5.6.1)" "Air Content of Fresh Concrete - Pressure Method: After rodding each layer, what should be done to the measure before adding another layer of concrete? - CORRECT ANSWER Rap the sides of the measure 10 to 15 times with the mallet. (Reference 5.6.1)" "Air Content of Fresh Concrete - Pressure Method: What tools may be used to strike off the top surface of the concrete following consolidation of the final layer? - CORRECT ANSWER A strike-off bar or plate. (Reference 5.6.2)" "Air Content of Fresh Concrete - Volumetric Method (Roll-A-Meter): The volumetric method of determining air content of the concrete can be used on the concrete containing what types of aggregate? - CORRECT ANSWER All types of aggregate. (Reference 6.2)" "Air Content of Fresh Concrete - Pressure Method: What type of alcohol and concentration must be used in this test method? - CORRECT ANSWER Isopropyl, 70% by volume. (Reference 6.4.2)" "Air Content of Fresh Concrete - Pressure Method: A mallet weighing ________________________________ must be used to tap the sides of the bowl after rodding each layer. - CORRECT ANSWER 1.25 +/- 0.50 lb (600 +/- 200 g) (Reference 6.4.2)" "Air Content of Fresh Concrete - Pressure Method: If the concrete mixture contains aggregate that would be retained on the ______________________ sieve, you must wet screen a representative portion of the concrete sample over a(n) ____________________ sieve. - CORRECT ANSWER 1-1/2-in. (37.5 mm); 1-in. (25 mm) (Reference 6.4.3)" "Air Content of Fresh Concrete - Pressure Method: When filling the measuring bowl of the air meter, the concrete must be placed in _____ layers of equal volume. - CORRECT ANSWER Two (Reference 6.6.2)" "Air Content of Fresh Concrete - Pressure Method: What is the specified number of strokes required when rodding each layer of concrete? - CORRECT ANSWER 25 (Reference 6.6.2)" "Air Content of Fresh Concrete - Pressure Method: It is necessary to tap the sides of the measuring bowl after each layer has been rodded. True or False? - CORRECT ANSWER True (Reference 6.6.2)" "Air Content of Fresh Concrete - Pressure Method: 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? - CORRECT ANSWER False; the funnel must be used. (Reference 6.6.4)" "Air Content of Fresh Concrete - Pressure Method: 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? - CORRECT ANSWER Bottom of the meniscus (Reference 6.6.4)" "Air Content of Fresh Concrete - Pressure Method: How long should the air meter be inverted and agitated? - CORRECT ANSWER No more than 5 seconds at a time, but must be repeated for a minimum of 45 seconds to free the concrete from the base. (Reference 6.6.5)" "Air Content of Fresh Concrete - Pressure Method: How many times does the rolling operation occur? - CORRECT ANSWER A minimum of 2, a maximum of 3. (Reference 6.6.5)" "Air Content of Fresh Concrete - Pressure Method: Why is the isopropyl alcohol added to the meter? - CORRECT ANSWER To dispel any foam. (Reference 6.6.4)" "Air Content of Fresh Concrete - Pressure Method: The direct reading of the final liquid level in the neck of the air meter, is estimated to the nearest ________________. - CORRECT ANSWER 0.25% (Reference 6.6.5)" "Air Content of Fresh Concrete - Pressure Method: If the air content is greater than the 9% range of the meter, _______________________________________________________________. - CORRECT ANSWER Calibrated cups of water are added to bring the liquid level with the graduated range. (Reference 6.6.5)" "Air Content of Fresh Concrete - Pressure Method: In order for an initial meter reading to be valid, the meter must not be leaking, the liquid level must stabilize within 6 minutes, and the foam on the surface of the liquid must not be greater than 2 full percent divisions. True or False? - CORRECT ANSWER True (Reference 6.6.6)" "Air Content of Fresh Concrete - Pressure Method: If less than 2.5 pt (1.25 L) of alcohol are used, the air content is always indicated by the final meter reading. True or False? - CORRECT ANSWER False, the air content is calculated by adding the final reading with the number of calibrated cups, if any, and subtracting the correction factor based on the amount of alcohol added. (Reference 6.6.8)" "Air Content of Fresh Concrete - Pressure Method: If more than 2.5 pints of alcohol are used, the final meter reading is always adjusted using ________________________________________________________. - CORRECT ANSWER A correction factor (Reference 6.6.4 & Table 6.1)" "Air Content of Fresh Concrete - Pressure Method: At the end of the procedure, the air meter is __________________________________________________________________. - CORRECT ANSWER Disassembled and its contents examined. (Reference 6.6.7)" "Air Content of Fresh Concrete - Pressure Method: If portions of the undisturbed concrete are found in the air meter at the end of the test, ___________________________________________________________________________________________________. - CORRECT ANSWER The test is invalid. (Reference 6.6.7)" "Making and Curing Concrete Cylinders and Beams in the Field: For concrete with a slump of less than 1 in. (25 mm), the test specimens must be consolidated by ________________________. - CORRECT ANSWER Vibration (Reference 7.6.1)" "Making and Curing Concrete Cylinders and Beams in the Field: If the concrete is to be consolidated by vibration, a standard 4 by 8 in. (100 by 200 mm) cylinder mold must be filled in ______________________ equal layers. - CORRECT ANSWER 2 (Reference Table 7.1)" "Making and Curing Concrete Cylinders and Beams in the Field: When rodding a standard 6 by 12 in (150 by 300 mm) cylinder, each layer must be rodded ________________ times. - CORRECT ANSWER 25 (Reference Table 7.2)" "Making and Curing Concrete Cylinders and Beams in the Field: When rodding each upper layer of concrete in a cylinder, the tamping rod should penetrate into the underlying layer by about _____________________. - CORRECT ANSWER 1 in. (25 mm) (Reference 7.6.1.1)" "Making and Curing Concrete Cylinders and Beams in the Field: When using an internal vibrator to consolidate a 6 by 12 in. (150 by 300 mm) compressive strength test specimen, the vibrator must be inserted at ______________ different points for each layer. - CORRECT ANSWER 2 (Reference 7.6.1.2)" "Making and Curing Concrete Cylinders and Beams in the Field: Upon completion of initial curing, the test specimens may be left in the molds and sealed in plastic bags. True or False? - CORRECT ANSWER False; specimens are to be demolded and placed in water storage tanks or moist rooms with free water at a temperature of 73.5 +/- 3.5 degrees F (23 +/- 2 degrees C) (Reference 7.7.1)" "Making and Curing Concrete Cylinders and Beams in the Field: During transportation, test specimens must be protected from damage due to ____________________________, ___________________________________, and _________________________________________. - CORRECT ANSWER Jarring, extreme temperatures, and moisture loss. (Reference 7.7.1 Note)" "Making and Curing Concrete Cylinders and Beams in the Field: Specimens shall not be transported until _____________ after final set. - CORRECT ANSWER 8 hours (Reference 7.8)" "Making and Curing Concrete Cylinders and Beams in the Field: Transportation time shall not exceed ________________. - CORRECT ANSWER 4 hours (Reference 7.8)" "Making and Curing Concrete Cylinders and Beams in the Field: Keep field cured specimens under ____________________________________ conditions as the concrete placed for the structure. - CORRECT ANSWER The same (Reference 7.7.2)" “Sampling Fresh Concrete: Collecting a representative sample of concrete to be tested is as important as executing the test methods to obtain _______________________________. - CORRECT ANSWER Accurate results (Reference 1.2)" "Sampling Fresh Concrete: This practice covers sampling from four types of equipment , which are ________________________________, ________________________, ________________________________________, and _____________________ ____________. - CORRECT ANSWER Stationary mixers, paving mixers, revolving truck mixers, continuous mixers (Reference 1.5)" "Sampling Fresh Concrete: The elapsed time between obtaining the first and final portions of the composite sample shall not exceed ____________________. - CORRECT ANSWER 15 minutes (Reference 1.5)" "Sampling Fresh Concrete: When sampling from a paving mixer, obtain samples from a least ________ difference portions of the pile and combine them into one composite sample for test purposes. - CORRECT ANSWER Five (Reference 1.5.3)" "Sampling Fresh Concrete: When sampling from revolving truck mixer, sample the concrete by collecting ________ or more portions taken at regularly spaced intervals during discharge of the middle portion of the batch. - CORRECT ANSWER Two (Reference 1.5.2)" "Temperature of Fresh Concrete: The thermometer shall be capable of accurately measuring the temperature of freshly mixed concrete to _____________________ throughout a range of _________________________. - CORRECT ANSWER 1 degree F (+/- 0.5 degree C), 30 to 120 degree F (0 to 50 degree C) (Reference 2.3.2)" "Temperature of Fresh Concrete: The thermometer shall be verified within ___________________________________________________________________________. - CORRECT ANSWER At least one year of its current use. (Reference 2.3.2)" "Temperature of Fresh Concrete: The temperature of concrete may be measured in a wheelbarrow. True or False? - CORRECT ANSWER True (Reference 2.3.2)" "Temperature of Fresh Concrete: The temperature of concrete may be measured in a wall form. True or False? - CORRECT ANSWER True (Reference 2.3.2)" "Temperature of Fresh Concrete: What must be done to the concrete surrounding the thermometer after the device is submerged in the fresh concrete? - CORRECT ANSWER Push concrete around the stem to ensure the concrete is in full contact with the stem. (Reference 2.4)" "Temperature of Fresh Concrete: How long must the thermometer remain in the freshly mixed concrete? - CORRECT ANSWER For 2-5 minutes. (Reference 2.4)" "Temperature of Fresh Concrete: After the temperature of the concrete is read, what is then required? - CORRECT ANSWER Record the temperature. (Reference 2.4)" "Temperature of Fresh Concrete: The temperature of the concrete is recorded to the nearest ______________. - CORRECT ANSWER 1 degrees F (0.5 degrees C) (Reference 2.4)" "Slump of Fresh Concrete: The slump mold should be in a dry condition before beginning the test. True or False? - CORRECT ANSWER False (Reference 3.5)" "Slump of Fresh Concrete: The surface on which the slump mold will be placed must be _________________, __________________, _______________, _________________________, and ____________________. - CORRECT ANSWER Flat, level, damp, nonabsorbent, and rigid. (Reference 3.5)" "Slump of Fresh Concrete: The slump mold is filled in _______________ layers. - CORRECT ANSWER Three (Reference 3.5)" "Slump of Fresh Concrete: Each layer should be filled approximately ____________________ the volume of the mold. - CORRECT ANSWER One-third (Reference 3.5)" "Slump of Fresh Concrete: What must be done if the concrete drops below the top of the slump mold while the top layer is being rodded? - CORRECT ANSWER Add additional concrete to keep an excess of concrete above the top of the mold. (Reference 3.5)" "Slump of Fresh Concrete: The measurement for slump is made from the top of the mold to what point of the concrete specimen? - CORRECT ANSWER The displaced original center of the top surface of the specimen. (Reference 3.5)" "Slump of Fresh Concrete: The slump of the concrete is measured and reported to the nearest _____________________________. - CORRECT ANSWER 1/4 in. (5 mm) (Reference 3.5)" "Slump of Fresh Concrete: How much time is allowed to conduct the slump test from beginning to completion? - CORRECT ANSWER 2-1/2 minutes (Reference 3.5)" "Density (Unit Weight) and Yield of Fresh Concrete: What is the required shape of the tamping end of the rod? - CORRECT ANSWER Rounded to a hemispherical tip. (Reference 4.5.2)" "Density (Unit Weight) and Yield of Fresh Concrete: What is the required minimum frequency of the vibrator used in this test method? - CORRECT ANSWER 9,000 vibrations per minute (150 Hz) (Reference 4.5.2)" "Density (Unit Weight) and Yield of Fresh Concrete: The outside diameter or side dimension of the vibrating element must be at least ____________________ but not greater than _____________________. - CORRECT ANSWER 0.75 in. (19 mm), 1.50 in. (38 mm) (Reference 4.5.2)" "Density (Unit Weight) and Yield of Fresh Concrete: What is the specified weight of the mallet used on measures that are 1/2 ft^3 (14 L) or smaller? - CORRECT ANSWER 1-1/4 +/- 1/2 lb. (600 +/- 200 g) (Reference 4.5.2)" "Density (Unit Weight) and Yield of Fresh Concrete: What method of consolidation must be used when the slump is greater than 3 in. (75 mm)? - CORRECT ANSWER Rodding (Reference 4.7.1)" "Density (Unit Weight) and Yield of Fresh Concrete: What method of consolidation must be used when the slump is less than 1 in. (25 mm)? - CORRECT ANSWER Vibration (Reference 4.7.1)" "Density (Unit Weight) and Yield of Fresh Concrete: If rodding is the method of consolidation being used, the measure must be filled in how many layers? - CORRECT ANSWER Three (Reference 4.7.2.1)" "Air Content of Fresh Concrete - Pressure Method: What is the specified size of the mallet required for a typical air meter? - CORRECT ANSWER 1-1/4 +/- 1/2 lb (600 +/- 250 g) (Reference 5.4.2)" "Air Content of Fresh Concrete - Pressure Method: Wet screening may be necessary when the mixture contains aggregate with a nominal maximum size greater than _______________________________________________________________. - CORRECT ANSWER 1-1/2 in (37.5 mm) (Reference 5.4.3)" "Air Content of Fresh Concrete - Pressure Method: If the concrete sample is to be consolidated by rodding, the measure is filled in ___________________________________ layers. - CORRECT ANSWER Three equal (Reference 5.6.1)" "Air Content of Fresh Concrete - Pressure Method: If the concrete sample is to be consolidated by vibration, the measure is filled in ___________________________________ layers. - CORRECT ANSWER Two equal (Reference 5.6.1)" "Air Content of Fresh Concrete - Pressure Method: When rodding the concrete sample, what is the specified number of strokes required for each layer? - CORRECT ANSWER 25 (Reference 5.6.1)" "Air Content of Fresh Concrete - Pressure Method: What are the requirements for the tamping rod used in this test method? - CORRECT ANSWER Steel or plastic, with a hemispherical tip on one or both ends, at least 4 in. (100 mm) taller than the height of the measure but no more than 24 in. (600 mm) in overall length. (Reference 6.4.2)" "Air Content of Fresh Concrete - Pressure Method: What are the requirements for the strike-off bar used in this test method? - CORRECT ANSWER Metal or plastic flat bar at least 3/4 in. (20 mm) in width and 12 in. (300 mm) in length. If using a meter made of metal, the thickness must be at least 1/8 in. (3 mm) and if using a meter made of plastic, the thickness must be at least 1/4 in. (6mm). (Reference 6.4.2)" "Air Content of Fresh Concrete - Pressure Method: What is the approximate capacity of the measuring cup used to add water to the air meter? - CORRECT ANSWER 1-pint (5 ml) (Reference 6.4.2)" "Making and Curing Concrete Cylinders and Beams in the Field: For cylinders with a diameter of 6 in. (150 mm) or greater, the tamping rod must have a diameter of ____________________. - CORRECT ANSWER 5/8 in. (16 mm) (Reference 7.4.2)" "Making and Curing Concrete Cylinders and Beams in the Field: The minimum frequency of an internal vibrator used in this procedure is ____________________________. - CORRECT ANSWER 9000 vibrations per minute (150 Hz) (Reference 7.4.2)" "Making and Curing Concrete Cylinders and Beams in the Field: Concrete containing aggregate with particles not exceeding ______________________________________ can be used to cast specimens without the need for a wet screening. - CORRECT ANSWER 2 in. (50 mm) (Reference 7.4.3)" "Making and Curing Concrete Cylinders and Beams in the Field: When consolidating a flexural strength test specimen by rodding, rod one stroke for each ________________ along the center line of the beam. - CORRECT ANSWER 2 in.^2 (14 cm^2) (Reference 7.6.1.1)" "Making and Curing Concrete Cylinders and Beams in the Field: When internal vibration is used to consolidate a standard flexural strength test specimen, the technician should insert the vibrator at intervals of ________________ along the center line of the beam. - CORRECT ANSWER 6 in. (150 mm) (Reference 7.6.2.2)" "Making and Curing Concrete Cylinders and Beams in the Field: Concrete mixtures with specified strengths of 6000 psi (40 MPa) or greater shall have an initial curing temperature between __________________________________________________. - CORRECT ANSWER 68 and 78 degrees F (20 and 26 degrees C) (Reference 7.7.1)"