ACI Concrete Field Testing Technician – Grade I - Q & A

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ACI Concrete Field Testing Technician – Grade I - Q & A (Answered) The sensor of the temperature measuring device shall be submerged a minimum of _____ in. [_____mm] into the freshly mixed concret... e. 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 _____. 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 _____. Annually, accuracy The temperature of concrete may be measured in a wheelbarrow. True or False? True The temperature of concrete may be measured in a wall form. True of False True A composite sample of concrete is required even if the only purpose for obtaining the sample is to determine temperature. True or False? 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 temperature measuring device after the device is submerged in the fresh concrete? 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? At least 2 minutes but not more than 5 minutes After the temperature of the concrete is read, what is required? Reporting of temperature The temperature of concrete is reported to the nearest _____ degrees F [_____ C] 1 degree F [0.5 C] According to ASTM C1064, what is one reason to take the temperature of concrete? Verify conformance to a specified requirement for temperature of concrete A maximum temperature of freshly mixed concrete is specified in ASTM C1064. True or False? False The sample of concrete used for temperature determination must be rodded 25 times. True or False? False Sampling by this method is required when tests are to be made to determine _____ with specification requirements. Compliance This method covers sampling from four types of mixtures which are _____, _____, _____, and _____. 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. 15 Portions of a composite sample shall be thoroughly remixed bfore beginning tests on the sample. True or False? 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. 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 for making strength test specimens 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 this 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. True or False? False The composite samples from a truck mixer must be obtained from the _____ portion of the batch. 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. Wet sieved The slump test is applicable to plastic concrete with a maximum size aggregate of _____. 1.5 in. [37.5 mm] When the concrete contains aggregate larger than allowed for the slump test, the large aggregate must be _____. 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 _____. The frustum of a cone The height of the slump mold is _____. 12 in. [300 mm] 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 _____. [Show More]

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