ACI Concrete Field Testing Technician- Exam Questions Answered Correctly Latest Version ()

ACI Concrete Field Testing Technician- Exam Questions Answered Correctly Latest Version () The sensor of the temperature measuring device shall be submerged a minimum of _____ in. [_____mm] into the freshly mixed concrete. - Answers 3 in. [75 mm] The temperature measuring device shall have a capacity of measuring temperature of freshly mixed concrete to +- _____ degrees F [+- _____ C] throughout a range of _____. - Answers 1 degree F [0.5 C], 30 degrees F to 120 F [0 C to 50 C] The temperature measuring device shall be calibrated _____, or whenever there is a question of _____. - Answers Annually, accuracy The temperature of concrete may be measured in a wheelbarrow. True or False? - Answers True The temperature of concrete may be measured in a wall form. True of False - Answers True A composite sample of concrete is required even if the only purpose for obtaining the sample is to determine temperature. True of False? - Answers False What must be done to the sample container prior to sampling the concrete? - Answers Dampen (with water) What must be done to the concrete surrounding the temperature measuring device after the device is submerged in the fresh concrete. - Answers Gently press the concrete around the temperature measuring device at the surface of the concrete How long must the temperature measuring device remain in the freshly mixed concrete? - Answers At least 2 minutes but not more than 5 minutes After the temperature of the concrete is read, what is required? - Answers Reporting of temperature The temperature of concrete is reported to the nearest _____ degrees F [_____ C] - Answers 1 degree F [0.5 C] According to ASTM C1064, what is one reason to take the temperature of concrete? - Answers Verify conformance to a specified requirement for temperature of concrete A maximum temperature of freshly mixed concrete is specified in ASTM C1064. True of False? - Answers False The sample of concrete used for temperature determination must be rodded 25 times. True or False? - Answers False Sampling by this method is required when tests are to be made to determine _____ with specification requirements. - Answers Compliance This method covers sampling from four types of mixtures which are _____, _____, _____, and _____. - Answers 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. - Answers 15 Portions of a composite sample shall be thoroughly remixed bfore beginning tests on the sample. True of False? - Answers 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. - Answers 5 The molding of strength test specimens shall begin within _____ minutes after fabricating the composite sample. - Answers 15 The concrete sample must be protected from contamination and _____. - Answers Rapid evaporation The minimum size sample for making strength test specimens is _____. - Answers 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 - Answers 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. - Answers 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 this batch. - Answers 2 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? - Answers False The composite samples from a truck mixer must be obtained from the _____ portion of the batch. - Answers Middle When the concrete contains aggregate larger than that permitted for a particular test method, the sample of concrete must be _____ _____ before making the test. - Answers Wet sieved The slump test is applicable to plastic concrete with a maximum size aggregate of _____. - Answers 1.5 in. [37.5 mm] When the concrete contains aggregate larger than allowed for the slump test, the large aggregate must be _____. - Answers Removed by wet sieving the sample over 1.5 in. [37.5 mm] sieve The mold for making the slump test is in the shape of _____. - Answers The frustum of a cone The height of the slump mold is _____. - Answers 12 in. [300 mm] The interior surface of the slump mold is allowed to have minor irregularities. True or False? - Answers False For use in the slump test, the end or both ends of the tamping rod must be _____. - Answers Rounded to a hemispherical tip The sample of concrete for use in making the slump test must be obained in accordance with ASTM Standard _____. - Answers C172, Standard Practice for Sampling Freshly Mixed Concrete The slump mold should be in a dry condition before beginning the test. True or False? - Answers False The surface on which the slump mold will be placed must be _____. - Answers Flat, level, moist, nonabsorbent, and free of vibration The slump mold is filled in _____ layers. - Answers 3 Each layer should fill approximately _____ the volume of the mold. - Answers One-third The approximate concrete depth (in verticle distance) after placing the first layer is _____, and the second layer is _____. - Answers 2 5/8 in. [70 mm], 6 1/8 in. [160 mm] What is the specified number of roddings for each layer? - Answers 25 How deep should the tamping rod penetrate into each layer? - Answers 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. - Answers Slightly inclined What must be done if the concrete drops below the top of the slump mold while the top layer is being rodded? - Answers 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 _____. - Answers The area surrounding the base of the mold After the final rodding, the sides of the slump mold should should be tapped lightly with the tamping rod. True or False? - Answers False When raising the slump mold, it should not be rotated or twisted, True or False? - Answers True How much time is allowed for lifting the slump mold? - Answers 5 +- 2 seconds The measurement for slump is made from the top of the mold to what point of the concrete specimen? - Answers The displaced original center of the top surface of the specimen The slump of the concrete is measured and reported to the nearest _____. - Answers 1/4 in. [5 mm] How much time is allowed to conduct the slump test from beginning to completion? - Answers 2 1/2 minutes The diameter of the tamping rod used in the test method is _____. - Answers 5/8 in. [16 mm] What is the required shape of the tamping end of the rod? - Answers Rounded to a hemispherical tip What is the required minimum frequency of the vibrator used in this test method? - Answers 7000 vibrations per minute The outside diameter or side dimension of the vibrating element must be at least _____ but not greater than _____. - Answers 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? - Answers False, measure must be steel or another suitable metal What is the minimum thickness of a metal strike-off plate? - Answers 1/4 in. [6 mm] What is the minimum thickness for a glass or acrylic strike-off plate? - Answers 1/2 in. [12 mm] What is the specified weight of the mallet used on measures that are 0.5 ft^3 [14 L] or smaller? - Answers 1.25 +- 0.50 lb. [600 +- 200 g] Measures other than air meter bowls used for this test must conform to ASTM _____. - Answers C29 Air meter bowls used for this test must conform to ASTM _____ and be calibrated for volumee according to ASTM _____. - Answers C231, C29 The concrete sample must be obtained in accodance with what ASTM method? - Answers C172 What method of consolidation must be used when the slump is greater than 3 in. [75 mm]? - Answers Rodding What method of consolidation must be used when the slump is less than 1 in. (25 mm]? - Answers Vibration If rodding is the method of consolidation being used, the measure must be filled in how many layers? - Answers 3