Download ACI WRITTEN EXAM 2024 and more Exams Nursing in PDF only on Docsity! 1 | P a g e ACI WRITTEN EXAM 2024 WITH ACTUAL CORRECT QUESTIONS AND VERIFIED DETAILED ANSWERS |FREQUENTLY TESTED QUESTIONS AND SOLUTIONS |ALREADY GRADED A+|NEWEST|GUARANTEED PASS|LATEST UPDATE The volumetric method of determining air content of concrete can be used on concrete containing what types of aggregates All types of aggregates What are the requirements of the tamping rod used in this method Round, straight 5/8 in, at least 4 in greater than depth of bowl, steel high density plastic with abrasion resistance What are the requirements for the strike off bar in this method Flat, straight steel bar at least 1/8 in by 3/4 in by 12 in. or high density plastic with abrasion resistance What is the approx volume of the measuring cup used to add water in relation to the volume of the air meter bowl 1 percent +- .04 percent What type of alcohol and concentration must be used in this test method isopropyl, 70 percent by volume A mallet weighing ____ must be used to tap the sides of the bowl after rodding each layer 1.25 +-.5 lb The sample of concrete used in this test must be obtained in accordance with ASTM satndard _____ 2 | P a g e C172 The max size aggregate allowed for this test method is ______ 1.5 in (37.5mm) If concrete sample has contains aggregates larger than that allowed for the test what must be done? wet sieved over a 1 in (25mm) sieve When filling the measuring bowl of the air meter the concrete must be placed in ____ layers 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 The initial quantitiy of water and alcohol added to the air meter can be directly poured into the neck of the top section of the air meter 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 for 45 seconds How many times does the rolling operation occur a minimum of 2, a max 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 percent If the air content is greater than 9% range of the meter then ____ Calibrated cups of water are added to bring liquid in 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 division 5 | P a g e Upon completion of initial curing the test specimens may be left in their molds and sealed in plastic bags False, specimens are to be demolded and placed in water storage tanks or moist rooms with free water at a temp of 73.5+3.5F (23.0 +2.0 C) During transportation, test specimens must be protected form damage due to _____, ______ and ______ Jarring, freezing temps, 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 Acceptance testing for spec strength, checking the adequacy of mixture proportions for strength, quality control Field curing is the curing method used for when Determination of whether structure is capable of being put into service 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 The temp 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 form the molds at the time of removal of formwork The sensor of the temperature measureing device shall be submerged a minimum of ____ in 3 (75mm) The temperature measureing device shall have a capacity of measuring temperature of freshly mixed conrcrete to +-_____ degrees F throught a range of _____ 1(.5 degrees C), 30-120 (0-50 degrees C) The temperature measuring device shall be calibrated____, or whenever there is a question of _____ annually, accuracy The temp of concrete may be measured in a wheelbarrow 6 | P a g e true the temp of concrete may be measured in a wall form true A composite sample of concrete is required even if the only purpose for obtaining the sample is to determine temp. false What must be done to the sample container prior to sampling the concrete dampen (with water) what must be done to the concrete surrounding the temp measuring device after the device has submerged Press concrete around measuring device How long must the temp device remain in the concrete at least 2 minutes (but no more than 5) After temp of concrete is read, what then is required reporting of temp the temp of concrete to be measured to the nearest ____degree F 1 (.5 degree C) According to the ASTM C1064 what is one reason to take the temp of concrete verify conformance to a specified requirement for temp A max temp of concrete is specified in ASTM C1064 False The sample of concrete used for temp determination must be rodded 25 times False Sampling by this method is required when tests are to be made to determine ____ with specification requirements compliance The method covers sampling from four types of mixers which are _____, _____, ____, and _______ stationary mixes, 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 7 | P a g e 15 Portions of a composite sample shall be thoroughly remixed before beginning tests on the sample True The maximum elapsed time allowed between obtaining the final portion of the composite sample and beginning the tests for slump, temp, and air content is ______ minutes 5 the molding of strength test specimens shall begin within ____ minutes after fabricating the composite sample 15 The concrete sample must be protected from contamination and ____ rapid evaporation The minimum size sample test specimen is 28 L (1ft^3) 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 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 5 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 2 Concrete samples from a truck mixer must be obtained before any water or admixtures are added to the mixer at the job site False The composite sample from a truck mixer must be obtained from the _____ portion of the batch Middle When the concrete contains aggregate larger than permitted for a particular test method, the sample fo concrete must be ______ ______ before making the test Wet Sieved The slump test is applicable to plastic concrete with a max aggregate size of ____ in 10 | P a g e False What is the min. thickness of the metal strike off plate 1/4 in (6mm) What is the min thickness for a glass or acrylic strike off plate 1/2 in (12mm) What is the specified weight of the mallet used on measures that are 0.5 ft^3 or smaller 1.25+-.5 lbs (600 +- 200g) 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 to what ASTM method C172 What method of consolidation must be used if slump is greater than 3 in. Rodding What method of consolidation must be used when the slump is less than 1 in. Vibration If rodding is the method of consolitdation being used, the measure must be filled in how many layers 3 for a measure of 0.5ft^3 what is the required number of strokes of the tamping rod for consolidation of each later 25 When rodding the middle and top layers the tamping rod should penetrate _____ in into the previous layer 1 (25mm) If vibration is the method of consolidation, the measure must be filled in _____ approx equal layers 2 If after consolidation of the final layer the concrete layer is 1/2 in (13 mm) above the top of the measure, what should be done? 11 | P a g e 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 1/8 in(3mm) After completing the strike off procedure, what must be done before weighing the measure and the sample Clean off any excess concrete The pressure method of determining air content can be used on concrete containing _________ _________ aggregate relatively dense The pressure method of determining air content can be used on concrete containing the following types of aggregate_____, ______, _______ lightweight, air cooled blast furnace slag, aggregates of high porosity What is the minimum allowable capacity of measuring bowl used in this test 6 L (0.20 ft^3) 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) +- 2mm (1/16in) diameter. Hemispherical tip What is the specified size of the mallet required for this test when measuring bowl has a capacity of 0.5 ft^3 0.6+- .25kg (1.25+-0.5lbs) The sample of concrete used for this test is to be obtained in accordance with astm Standard C172 The max size aggregate allowed for this method is 50 mm (2in) If the concrete contians aggregate larger than max allowed it must be wet sieved over a 1.5 in sieve vibration of the concrete sample is not allowed when slump exceeds 75 mm (3in) When consolidating the concrete by vibration how many times should the vibrator be inserted into each layer 3 12 | P a g e What tools may be used to strike off top surface strike off bar or acrylic plate False. Relatively dense The method of determining air content of concrete containing lightweight aggregate is the pressure method True Is the following statement true or false? When making a test cylinder from concrete being used in construction, the field technician must also measure the slump of the concrete. Disregard the test and retest on another portion of the sample. While the technician is checking the slump of the concrete, there is a decided falling away or shearing off of concrete from one side of the sample. What should the technician do? Determination that at least 8 hours has elapsed since final set. Preparation of specimens for transport includes: 4.8% If the aggregate correction factor for a given source of fine and coarse aggregate is found to be 0.2% in a pressure air meter, and an air content value of 5.0% is read on the gauge of the same air meter containing concrete with the same aggregate, what is the correct air content? Protected from jarring, moisture loss, and freezing Strength test specimens transported from the field to the testing laboratory must be: 5 MInutes Tests for slump and air content must be started within ________ after obtaining the final portion of the composite sample. 1 cubic foot The minimum size for samples to be used for strength test is: False Is the following statement true or false? After strike off of the measure used to determine density, a small quantity of concrete may be added to correct a deficiency. 60 to 80 degrees f (16 to 27 degrees C) For normal strength concretes, what temperature range must be maintained for test cylinders during initial curing? False 15 | P a g e 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" The interior surface of the slump mold is allowed to have minor irregularities. T/F False For use in the slump test, the tamping end or both ends of the tamping rod must be rounded to a hemispherical tip The slump mold should be in a dry condition before beginning the test. T/F False The surface on which the slump mold will be placed must be flat, level, damp, nonabsorbent, and rigid The slump mold is filled in __ layers. 3 Each layer should fill approximately __ the volume of the mold. 1/3 Rod each layer __ times uniformly over the cross section with the rounded end of the rod. 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" 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 told of the mold. 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. T/F 16 | P a g e False When raising the slump mold, it should not be rotated or twisted. T/F 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 1/4" How much time is allowed to conduct the slump test from beginning to completion? 2-1/2 minutes The length of the tamping rod used in this test method is at least 4" taller than the height of the measure but no more than 24" 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? 9000 vibrations per minute The outside diameter or side dimension of the vibrating element must be at least __ but not greater than __. 0.75", 1.5" What material is the measure made of? typically metal What is the minimum thickness of a metal strike-off plate? 1/4" What is the minimum thickness for a glass or acrylic strike-off plate? 1/2" What is the specified weight of the mallet used on measures that are ½ ft3 or smaller? 17 | P a g e 1.25 +/- 1/2 lb What method of consolidation must be used when the slump is greater than 3 inches? Rodding What method of consolidation must be used when the slump is less than 1 inch? Vibration If rodding is the method of consolidation being used, the measure must be filled in how many layers? 3 For a measure of ½ ft3, 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" 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 ½ inch above the top of the measure, what should be done? Remove enough concrete to ensure you have over-filled the measure to approximately ⅛" above the top of the measure. After completing the strike-off procedure, what must be done before weighing the measure and sample? Clean off any excess concrete The pressure method of determining air content can be used on concrete containing __ and __ aggregate. normal weight, heavy weight The pressure method of determining air content cannot be used on concrete containing the following: lightweight aggregates, aggregates of high porosity What is the specified size of the mallet required for a typical air meter? 1.25 +/- 1/2 lb Wet screening may be necessary when the mixture contains aggregate with a nominal maximum size greater than 20 | P a g e If portions of undisturbed concrete are found in the air meter at the end of the test, the test is invalid For cylinders with a diameter of 6 inch or greater, the tamping rod must have a diameter of 5/8" The minimum frequency of an interval vibrator used in this procedure is 150 Hz Concrete containing aggregate with particles not exceeding __ can be used to cast specimens without the need for wet screening. 2" For concrete, with a slump of less than 25 mm, the test specimens must be consolidated by vibration If the concrete is to be consolidated by vibration, a standard 4 by 8 inch cylinder mold must be filled in __ equal layers. 2 When using an interval vibrator to consolidate a 6 by 12 inch 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 in squared 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. 6" Concrete mixtures with specified strengths of 6000 psi or greater shall have an initial curing temperature between 68 and 78 F Upon completion of initial curing, the test specimens may be left in their molds and sealed in plastic bags. T/F False During transportation, test specimens must be protected from damage due to jarring, extreme temperatures, and moisture loss 21 | P a g e Specimens shall not be transported until __ after final set. 8 hours Transportation time shall not exceed 4 hours Keep field cured specimens under __ conditions as the concrete placed for the structure. the same The stem of the thermometer is submerged a minimum of __ into the freshly mixed concrete. 3" The thermometer shall be capable of accurately measuring the temperature of freshly mixed concrete to __ throughout a range of __ +/- 1 F, 30-120 F The thermometer shall be verified within at least one year of its current use The temperature of concrete may be measured in a wheelbarrow. T/F True The temperature of concrete may be measured in a wall form. T/F True A composite sample of concrete is required even if the only purpose for obtaining the sample is to determine temperature. T/F False What must be done to the sample container prior to sampling the concrete? Dampening 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. How long must the thermometer remain in the freshly mixed concrete? 2-5 minutes After the temperature of the concrete is read, what is then required? Record the temperature The temperature of the concrete is recorded to the nearest 22 | P a g e 1 F There is a specified maximum temperature of freshly mixed concrete. T/F False The sample of concrete used for temperature determination must be rodded 25 times. T/F False