PCC Level 1 Questions and Answers

PCC Level 1 Questions and Answers The end of the temperature sensing portion of the temperature measuring device is submerged a minimum of ___ into the freshly mixed concrete. 3 inches The temperature measuring device shall be capable of accurately measuring the temperature of freshly mixed concrete to _____ throughout a range of _____ . 1 °F , 30-120°F Previous Play Next Rewind 10 seconds Move forward 10 seconds Unmute 0:00 / 0:15 Full screen Brainpower Read More The temperature measuring device shall be verified ______, or whenever there is a question of ______. annually, accuracy The temperature of concrete may be measured in a wheelbarrow. T or F? T The temperature of concrete may be measured in a wall form. T or F? T A composite sample of concrete is required even if the only purpose for obtaining the sample is to determine temperature. T or F? F What must be done to the sample container prior to sampling the concrete? Dampened with water What must be done to the concrete surrounding the temperature measuring device after the device is submerged in 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? 2-5 minutes After the temperature of the concrete is read, what is then required? Reporting of temperature The temperature of the concrete is reported to the nearest _____. 1°F According to Test Method C1064, what is one reason to take the concrete temperature? Verify conformance to a specified requirement for concrete temperature. A maximum temperature of freshly mixed concrete is specified in Test Method C1064. T or F? F The sample of concrete used for temperature determination must be rodded 25 times. T or F? F Sampling by this practice covers procedures for obtaining representative samples, on which tests are to be performed to determine ____ with quality requirements of the specification under which the concrete is furnished. Compliance This practice covers sampling from five types of equipment which are... Stationary mixers, paving mixers, revolving drum mixers, continuous mixers, and open top mixers. The elapsed time between obtaining the first and final portions of a composite sample shall not exceed ___. 15 minutes Portions of a composite sample shall be thoroughly remixed before beginning tests on the sample. T or F? T Start the tests for slump, temperature, and air content within how many minutes after obtaining the final portion of the composite sample? 5 minutes Start molding specimens for strength tests within how many minutes after fabricating the composite sample? 15 minutes The concrete sample must be protected from contamination and _____. Rapid evaporation The minimum size sample for making strength test specimens is _____. 1 cubic foot 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 When sampling from a paving mixer, obtain samples from at least ____ different portions of the pile and combine them into one composite sample for testing purposes. 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 jobsite. T or F? F The composite sample from a truck mixer must be obtained form 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 aggregate size of ____. 1.5" When the concrete contains aggregate larger than allowed for the slump test, the large aggregate must be ____. Removed by wet sieving the sample The mold for making the slump test is in the shape of ____. The frustum of a cone The height of a slump mold is _____. 12 in The interior surface of the slump mold is allowed to have minor irregularities. T or F? F The sample of concrete for use in making the slump test is in accordance with practice ____. C172 The slump mold should be in dry condition prior to slump test. T or F? F The surface on which the slump mold will be placed must be __________. Flat, moist, nonabsorbent, and rigid The slump mold is filled in _____ layers. 3 layers Each layer should fill approximately _____ the volume of the mold. 1/3 The approximate concrete depth (in vert distance) after placing the first layer is ____. 2-5/8" 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 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 drips below the top of the slump mold while the top layer is being rodded? Add additional concrete to keep and 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. T or F? F When raising the slump mold, it should not be rotated or twisted, True or False? T How much time is allowed for lifting the slump mold? 3-7 seconds The measurement for slump is made from the tip of the mold to what point of the concrete specimen? Displaced original center of the top surface of the specimen The slump of the concrete is measured and reported to the nearest ____. 1/4 inch How much time is allowed to conduct the slump test from beginning to completion? 2.5 minutes For use in the slump test, the tampering and or both ends must be hemispherical The outside diameter or side dimension of the vibrating element must be _____ - _____. 0.75-1.50" What is the minimum thickness of a metal strike off plate? 1/4 inch What is the minimum thickness for a glass or acrylic strike off plate? 1/2 inch What is the specified weight of the mallet used on measures that are 0.5 cubic foot or smaller? 1.25 +- 0.50 lb 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 volumee according to ASTM _____. C231 , C29 The concrete sample must be obtained in accodance with what ASTM method? C172 Density= (accuracy?) Net weight of concrete (lb)/Volume of concrete (ft^3) tenth of lb/cubic foot Concrete yield (in what units?)= Total mass of materials batched from ticket/(Measured density of concrete lb/ft3 • 27 ft3/yd3) yd^3 Relative yield (make sure you either meet or exceed spec)= Actual yield/design yield greater than 1 means you met/exceeded spec, less than one means you did not meet it Measured air content= (theoretical denity-actual density)/theoretical density • 100% or (big#-little#)/big#•100