ACI Test: Comprehensive Questions and Answers for Concrete Testing, Exams of Construction

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ACI Test | Comprehensive Questions and Answers Latest Updated 2024/2025 With 100% Verified Solutions The total time allowed between obtaining the first and final portions of a composite sample is - ✔✔15 minutes When it is necessary to wet sieve the concrete sample, wet sieving should be performed after the individual samples are remixed into a composite sample (T or F) - ✔✔F Tests for slump, temperature, and air content must begin within ______ minutes after obtaining the composite sample - ✔✔5 minutes Begin molding test specimens within ______ minutes after obtaining the composite sample - ✔✔15 minutes The concrete samples should be protected from - ✔✔the sun, wind, and other sources of rapid evaporation, from contamination When test specimens are to be molded, the minimum size of sample obtained is - ✔✔28 L (1 ft^3) The primary objective of the sampling process is to obtain a representative sample (T or F) - ✔✔T When sampling from a revolving drum truck mixer collect concrete from ______ portions of the batch - ✔✔2 or more Wet sieving is performed - ✔✔when the concrete contains aggregates larger than appropriate for a test When sampling from a paving mixer it is not acceptable to place 3 small containers on the sub grade in order to obtain the required samples of concrete (T or F) - ✔✔F TEMPERATURE - ✔✔ it may require up to ___ min before the temp stabilizes when the NMS of the coarse agg is greater than ___ - ✔✔20min., 3in. The container for the concrete shall be large enough to provide at least ___ inches, or _____ of coarse agg, of concrete in all directions around the TMD - ✔✔3in., 3 x NMS The temperature measuring device shall have the capability of measuring the temperature of the freshly mixed concrete to ± ______ oF accuracy and have a range of ______ to ______ oF. - ✔✔1,30to120 A composite sample of concrete is not required even if the only purpose for obtaining the sample is to determine temperature. T or F - ✔✔T The Temperature Measuring Device used for determining concrete temperature must be calibrated ______ or whenever there is a question of accuracy. - ✔✔annually The temperature of freshly mixed concrete can be measured in - ✔✔all of the above Submerge the sensing portion of the thermometer at least ______ inches into the concrete - ✔✔3 Gently press concrete around the thermometer such that the_______ does not affect the reading. - ✔✔ambient air temp The thermometer must remain in the concrete during the measurement for a minimum of ______ minutes. In addition, the temperature measurement must be completed within _______ minutes after obtaining the sample. - ✔✔2, 5 The temperature of freshly mixed concrete is measured and recorded to the nearest _____ - ✔✔1 degree 4. Wet sieve a sufficient amount of material for the volumetric air content test over a ______ in. sieve when the coarse aggregate for the mixture can be retained on a 1.5in. sieve. - ✔✔1 5. The bowl of the volumetric meter is filled in ______ layers of equal depth. - ✔✔2 6. The excess concrete above the rim of the bowl is struck off using - ✔✔strike off bar 7. Prior to adding any isopropyl alcohol to the meter, it is necessary to add at least ____ of water. - ✔✔1 pint 8. The meter should be inverted and agitated for at least - ✔✔45 sec . The rolling process should be continued for a minimum of - ✔✔1min 10. The liquid level in the neck of the meter is stabilized when - ✔✔the liquid level does not change more than 0.25% within a 2 minute period 11. Whenever a reading of the liquid level is taken, the reading is rounded to the nearest - ✔✔0.25% 12. If the foam in the neck of the meter is equivalent to ______ percent air content divisions, or more, the sample must be discarded and test rerun. - ✔✔2 Confirmation of the initial meter reading is obtained when the difference between the initial and final meter readings are within ________ of each other. - ✔✔0.25% If the concrete found in the bottom of the bowl is found to be undisturbed and tightly packed, adhering to the bowl of the volumetric meter when emptied, - ✔✔b. the test is invalid and the sample should be discarded. The final meter reading from the neck is found to be 5.5%. Three pints of alcohol were added with the water, given a correction factor of 0.3. The final air content for this test is________. - ✔✔. 5.5 - 0.3 = 5.2, rounded to 5.25%. UNIT WEIGHT YIELD AND AIR CONTENT - ✔✔ The size of the measure used in determining the density of fresh concrete _______. - ✔✔c. is based on the nominal maximum size aggregate ****. It is not allowable to use the bowl from the volumetric air meter test to determine the density of fresh concrete, when the NMAS is 1 inch or less. - ✔✔ 3. The appropriate method of consolidation, when the slump of the fresh concrete is less than 1 inch, is to use _______. - ✔✔a vibrator 4. The rod should __________________________when rodding the second and third layers of concrete in the measure. - ✔✔c. penetrate the underlying layer about 1 inch. When a vibrator is used to consolidate the concrete in the measure, fill the measure in ______ equal layers. - ✔✔2 6. After completing the consolidation portion of the test, it is optimal to have approximately 1/8 inch of excess concrete above the rim of the measure. - ✔✔T It is allowable to add a small quantity of concrete to the measure to correct a deficiency. - ✔✔T 8. To insure that the measure is completely full with concrete and the surface is level, strike off the top surface of concrete using ________. - ✔✔only strike off plate In order to determine the density of fresh concrete, it is necessary to determine __________. - ✔✔the weight and volume of the filled measure as well as the weight of the empty measure. Yield represents the ________. - ✔✔d. volume of concrete produced per batch MAKING AND CURING CONCRETE - ✔✔ 1. The standard sized flexural strength specimen has cross-sectional dimensions of - ✔✔6in. x 6in 2. The standard sized compressive cylinder and flexural beam molds are used for concrete with nominal maximum sized coarse aggregate up to _________. - ✔✔2 in A flexural beam is filled in ______ layer(s) of approximately equal depth. - ✔✔2 ACI Field Testing Technicians, Grade I or equivalent certification is not required is required when testing for slump, air content, and density, but not for making test specimens.. - ✔✔F When test specimens are to be molded, it is not necessary to determine the slump, air content, and temperature of fresh concrete. - ✔✔F 6. Single-use cylinder molds that are susceptible to damage when tapped with a rubber mallet should instead by tapped 10 to 15 times with - ✔✔with an open hand 7. Concrete test specimens with a specified compressive strength less than 6,000psi, should be initially cured in a temperature range from - ✔✔60 to 80 Initial curing must continue for a period - ✔✔up to 48 hours Test specimens shall not be transported until at least ______ hours after initial set has occurred. - ✔✔8