ACI Concrete Field-Testing Technician Grade I Certification Exam V2 (Latest Update 2026 / 2027) Questions & Answers | Grade A | 100% Correct

ACI Concrete Field-Testing Technician Grade I Certification Exam V2 (Latest Update 2026 / 2027) Questions & Answers | Grade A | 100% Correct Question: ASTM C1064 Answer Standard Test Method For Temperature of Freshly Mixed Hydraulic-Cement Concrete Question: The sensor of the temperature measuring device shall be submerged a minimum of ______ inches into the freshly mixed concrete. Answer 3" Question: 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 Question: The temperature measuring device shall be calibrated ______ , or whenever there is a question of ______ . Answer Annually, accuracy Question: The temperature of concrete may be measured in a wheelbarrow. True or False? Answer True Question: The temperature of concrete may be measured in a wall form. True or False? Answer True Question: What must be done to the sample container prior to sampling the concrete? Answer Dampen with water Question: 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 Question: How long must the temperature measuring device remain in the freshly mixed concrete? Answer minimum of two minutes, maximum of five minutes Question: The temperature of the concrete is reported to the nearest ______ °F Answer 1 degree Question: A maximum temperature of freshly mixed concrete is specified in ASTM C1064. True or False? Answer False Question: ASTM C172 Answer Standard Practice for Sampling Freshly Mixed Concrete Question: Sampling by this method is required when tests are to be made to determine _____ with specification requirements. Answer Compliance Question: This method covers sampling from four types of mixers, which are _____ , _____ , _____ , and _____ . Answer Stationary mixers, paving mixers, revolving drum mixers and open top mixers Question: The maximum allowable time between obtaining the first and final portions of a composite sample is _____ minutes. Answer 15 Question: Portions of a composite sample shall be thoroughly remixed before beginning tests on the sample. True or False? Answer True Question: 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 Question: The molding of strength test specimens shall begin within _____ minutes after fabricating the composite sample. Answer 15 Question: The concrete sample must be protected from contamination and _____. Answer Rapid evaporation Question: The minimum size sample for making strength test specimens is _____. Answer 1 cubic foot Question: 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. Answer 2 Question: The composite sample for a paving mixer must represent a minimum of _____ different portions of the batch of concrete taken from the pile after discharge. Answer 5 Question: When sampling from a revolving drum truck mixer, concrete must be sampled at a minimum of _____ regularly spaced intervals during discharge of the middle portion of the batch. Answer 2 Question: 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? Answer False Question: The composite sample from a truck mixer must be obtained from the _____ portion of the batch. Answer middle Question: When the concrete contains aggregate larger than that permitted for a particular test method, the sample of concrete must be _____ _____ before making the test. Answer wet sieved Question: What must occur before a sample of concrete can be taken from a revolving drum mixer? (Oral Exam) Answer All of the water must be added to the mixer Question: Describe the different procedures that can be used to collect a sample of concrete from a stationary or revolving drum mixer. (Oral Exam) Answer Repeatedly pass a receptacle through the entire discharge stream, Completely divert the discharge stream into a sample container Question: 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 Question: 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 Question: What is the minimum size for a sample when strength test specimens are to be molded? (Oral Exam) Answer 1 cubic foot (28 L) Question: What is the maximum allowable time between obtaining the first and final portions of the composite sample? (Oral Exam) Answer 15 min. Question: 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) Sun, wind, rapid evaporation, and contamination ASTM C143 Standard Test Method for Slump of Hydraulic-Cement Concrete The slump test is applicable to plastic concrete with a maximum size aggregate of _____ . 1½ in. When the concrete contains aggregate larger than allowed for the slump test, the large aggregate must be _____. Removed by wet sieving the sample over 1½ in. sieve The mold for making the slump test is in the shape of _____. The frustum of a cone The height of the slump mold is _____. 12 in. The interior surface of the slump mold is allowed to have minor irregularities. True or False? False For use in the slump test, the end or both ends of the tamping rod must be _____. Rounded to a hemispherical tip The sample of concrete for use in making the slump test must be obtained in accordance with ASTM Standard _____. C172, Standard Practice for Sampling Freshly Mixed Concrete The slump mold should be in a dry condition before beginning the test. True or False? False The surface on which the slump mold will be placed must be _____. Flat, level, moist, nonabsorbent, and free of vibration The slump mold is filled in _____ layers. 3 Each layer should fill approximately _____ the volume of the mold. One-third The approximate concrete depth (in vertical distance) after placing the first layer is _____, and the second layer is _____. 2⅝ in. [70 mm], 6⅛ in. [160 mm] What is the specified number of roddings for each layer? 25 How deep should the tamping rod penetrate into each layer? 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] When rodding the bottom layer, the tamping rod must be _____ to uniformly distribute the strokes. Slightly inclined 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 of concrete above the top of the mold at all times Prior to lifting the mold, concrete must be removed from _______. The area surrounding the base of the mold After the final rodding, the sides of the slump mold should be tapped lightly with the tamping rod. True or False? False When raising the slump mold, it should not be rotated or twisted. True or False? True How much time is allowed for lifting the slump mold? 5 ± 2 seconds The measurement for slump is made from the top of the mold to what point of the concrete specimen? The displaced original center of the top surface of the specimen The slump of the concrete is measured and reported to the nearest _____. ¼ in. [5 mm] How much time is allowed to conduct the slump test from beginning to completion? 2½ minutes ASTM C138 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 _____ . ⅝ in. [16 mm] What is the required shape of the tamping end of the rod? Rounded to a hemispherical tip What is the required minimum frequency of the vibrator used in this test method? 7000 vibrations per minute The outside diameter or side dimension of the vibrating element must be at least _____ but not greater than _____ . 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? False, measure must be steel or other suitable metal What is the minimum thickness of a metal strike-off plate? ¼ in. [6 mm] What is the minimum thickness for a glass or acrylic strike-off plate? ½ in. [12 mm] What is the specified weight of the mallet used on measures that are 0.5 ft3 [14 L] or smaller? 1.25 ± 0.50 lb. [600 ± 200 g] Measures other than air meter bowls used for this test must conform to ASTM _____. C29 Air meter bowls used for this test must conform to ASTM _____ and be calibrated for volume according to ASTM _____. C231, C29 The concrete sample must be obtained in accordance with what ASTM method? C172 What method of consolidation must be used when the slump is greater than 3 in. [75 mm]? Rodding What method of consolidation must be used when the slump is less than 1 in. [25 mm]? Vibration If rodding is the method of consolidation being used, the measure must be filled in how many layers? 3 For a measure of 0.5 ft3 [14 L], what is the required number of strokes of the tamping rod for consolidation of each layer? 25 When rodding the middle and the top layers, the tamping rod should penetrate into the layer below approximately _____. 1 in. [25 mm] If vibration is the method of consolidation, the measure must be filled in _____ approximately equal layers. 2 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? Remove a representative portion of the excess concrete with a trowel or scoop After consolidation of the final layer, an excess of concrete _____ above the top of the measure is considered optimum. ⅛ in. [3 mm] After completing the strike-off procedure, what must be done before weighing the measure and sample? Clean off any excess concrete Density (Unit Weight) Calculation Known: Volume of measure = 0.504 ft3 [14.27 L or 0.01427 m3] Mass of empty measure = 19.6 lb [8.89 kg] The procedures of Method C138 are followed, and the mass of the measure plus the concrete is found to be 92.1 lb [41.78 kg]. Calculate the density of the concrete in lb/ft3 [kg/m3]. 143.9 lb/ft3 [2305 kg/m3] Yield Calculations For a design batch of 7.0 yd3 [5.4 m3], the total mass of all materials batched was 27,300 lb [12,383 kg]. Using the density of the concrete as determined in Question 21, calculate: a) The yield per batch in ft3 b) The yield per batch in yd3 c) The yield in m3 d) The yield per cubic yard in ft3/yd3 a. Yield per batch = 189.7 ft3 b. Yield per batch = 7.0 yd3 c. Yield per batch = 5.4 m3 d. Yield per cubic yard = 27.1 ft3/yd3 Relative Yield Calculation Using the information given and calculated in Question 22, calculate the relative yield for the batch of concrete. 1.00 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/ft3 (2425 kg/m3). Using the density calculated in Question 21, calculate the air content of the batch (in percentage). 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 StandardTestMethodforAirContentofFreshlyMixedConcretebythePressureMethod The pressure method of determining air content can be used on concrete containing _____ _____ aggregate. Relatively Dense The pressure method of determining air content cannot be used on concrete containing the following types of aggregate: _____, _____, _____. 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? 6 L (0.20 ft3) What are the required characteristics of the tamping rod used in this test method? 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. 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? 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? C172 The maximum size aggregate allowed for this test method is _____. 50 mm (2 in.) If the concrete contains aggregate larger than the maximum allowed for this test, the sample must be _____. 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. 3 equal If the concrete sample is to be consolidated by vibration, the measure is filled in ______ layers. 2 equal When rodding the concrete sample, what is the specified number of strokes required for each layer? 25 Vibration of the concrete sample is not allowed when the slump of the concrete exceeds _____. 75 mm (3 in.) In rodding the sample, how deep should the rod penetrate each layer? Rod bottom layer to full depth; rod second and final layer penetrating the previous layer about 25 mm (1 in.) After rodding each layer, what should be done to the measure before adding another layer of concrete? Tap the sides of the measure smartly 10 to 15 times with the mallet When consolidating the concrete by vibration, how many times should the vibrator be inserted into each layer? Three (3) What tools may be used to strike off the top surface of the concrete following consolidation of the final layer? A strike-off bar; a metal, glass, or acrylic plate What must be done if there is a slight deficiency in the quantity of concrete in the measure following consolidation of the final layer? Add a quantity of representative concrete before strike off What must be done if there is an excessive amount of concrete in the measure following consolidation of the final layer? Remove a representative quantity of concrete with the scoop or trowel before the strike off ASTM C173 Standard Test Method For Air Content of Freshly Mixed Concrete by the Volumetric Method The volumetric method of determining air content of concrete can be used on concrete containing what types of aggregate? All types of aggregate What are the requirements for the tamping rod used in this test method? 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? 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? 1.00% ± 0.04% What type of alcohol and concentration must be used in this test method? Isopropyl, 70% by volume (65% by weight) A mallet weighing _____ must be used to tap the sides of the bowl after rodding each layer. 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? C172 The maximum size aggregate allowed in this test method is _____. 1½ in. (37.5 mm) If the concrete sample contains aggregate larger than that allowed for this test, the sample must be _____. 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. 2 What is the specified number of strokes required when rodding each layer of concrete? 25 It is necessary to tap the sides of the measuring bowl after each layer has been rodded. True or False? 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? 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? Bottom of the meniscus How long should the air meter be inverted and agitated? 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? A minimum of 2, a maximum of 3 Why is the isopropyl alcohol added to the meter? To dispel any foam that may be on the surface of the water The direct reading of the final liquid level in the neck of the air meter, is estimated to the nearest _____. 0.25% If the air content is greater than the 9% range of the meter, __________. Calibrated cups of water are added to bring the liquid level within the graduated range 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? True If less than 1.25 L [2.5 pt] of alcohol are used, the air content is always indicated by the final meter reading. True or False? 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 If more than 1.25 L [2.5 pt] of alcohol are used, the final meter reading is always adjusted using _______. A correction factor When large amounts of alcohol are used, the direct reading will tend to indicate a __________ air content. Higher At the end of the procedure, the air meter is _______. Disassembled and its contents examined If portions of undisturbed concrete are found in the air meter at the end of the test, _________. The test is invalid ASTM C31 Standard Practice for Making and Curing Concrete Test Specimens in the Field ASTM Method C31 gives standardized requirements for _____, _____, _____, and _____, of test specimens. 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 _____. 5/8 ± 1/16 in. [16 mm ± 2 mm] The minimum frequency of an internal vibrator used in this procedure is _____ . 9000 vibrations per minute [150 Hz] The container for obtaining the concrete sample used in this procedure can be a _____, _____, or _____ . 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. 2 in. [50 mm] The sample of concrete used in molding test specimens must be obtained in accordance with what ASTM Standard? C172 When strength specimens are to be made, what three other tests must be made? 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? False; the specimens must be moved immediately The supporting surface on which specimens are stored shall be level within ______. 1/4 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 _____. Vibration If the concrete is to be consolidated by vibration, a standard 4 by 8 in. [100 mm by 200 mm] cylinder mold must be filled in _____ equal layers. 2 When rodding a standard 6 by 12 in. [150 mm by 300 mm] cylinder, each layer must be rodded _____ times. 25 When rodding each upper layer of concrete in a cylinder, the tamping rod should penetrate into the underlying layer by about _____. 1 in. [25 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. 2 When consolidating a flexural strength test specimen by rodding, rod one stroke for each _____ of top surface area. 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. 6 in. [150 mm] Concrete mixtures with specified strengths of 6000 psi [40 MPa] or greater shall have an initial curing temperature between ___________. 68 and 78 ºF [20 and 26 ºC] Up to 48 hours after molding, test specimens that are to be standard cured shall be stored in a temperature range between _____ to _____. 60 and 80 ºF [16 and 27 ºC] Upon completion of initial curing, the test specimens may be left in their molds and sealed in plastic bags. True or False? 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 °F [23.0 ± 2.0 °C] During transportation, test specimens must be protected from damage due to _____, _____, and _____ . Jarring, freezing temperatures, moisture loss Specimens shall not be transported until _______ after final set. 8h Transportation time shall not exceed _____________ . 4h Standard Curing is the curing method used when test specimens are to be used for ______________. Acceptance testing for specified strength, checking the adequacy of mixture proportions for strength, quality control Field Curing is the curing method used when test specimens are to be used for ______________. Determination of whether the structure is capable of being put into service; Comparison with standard cured specimens test results or with results from various in-place test methods; Adequacy of curing and protection of concrete in the Structure, or Form or shoring removal time requirements Cylinders that are to be field cured are stored ___________________________ and protected _______. 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 The temperature and moisture environment for field cured cylinders must be _____________________________________________________________________________. 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 _________________________________________________________. At the time of the removal of formwork