ACI Test Questions

ASTM C138, Calculate the density of concrete in pounds per cubic foot, given the following information: Volume of measure: 0.400 ft Mass of empty measure: 17.0 lb Mass of measure plus concrete: 76.0 lb

147.5=(76.0-17.0)/0.400

ASTM C172, The elapsed time between obtaining the first and final portion of the composite sample shall not exceed:

15 min

ASTM C172, start molding specimens for strength test within ______ when fabricating the composite sample:

15 min

According to practice C172 the minimum size of the sample to be used for strength test is:

28 L(1 ft)

According to test method C231/C231M, the optimum amount of concrete removed during strike off is:

3mm(1/8 in.)

ASTM C1064, Leave the temperature measuring device in the freshly mixed concrete for not more than:

5 min

ASTM C143, After the top layer has been rodded, the surface of the concrete is struck off by means of:

A screeding and rolling motion of the tamping rod

ASTM C143, the slump mold is filled in three layers of:

Approximately equal volume

ASTM C173, The addition of alcohol to dispel foam after the initial filling of the meter to the zero mark is:

Not permited

ASTM C 231, Is the following statement true or false? If water collects in the air chamber of a type B meter, it must be bled to prevent error in subsequent measurements.

True

ASTM C231, Is the following statement true or false? According to test method C231/C231M, the aggregate correction factor must be determined in order to accurately calculate air content.

True

ASTM C173, After an initial meter reading has been recorded, the next meter reading should be recorded as the final meter reading if this meter reading has not changed more than ______ from the initial meter reading:

0.25%

ASTM C173, The air content as determined by the volumetric method is reported to the nearest:

0.25%

ASTM C1064, The measured temperature of the freshly mixed concrete must be reported to the nearest:

0.5C(1 F)

ASTM C143, The measuring device used to measure the slump must be marked in increments of ______ or smaller.

1/4 in (5mm)

ASTM C31, For acceptance testing for specified compressive strength, cylinders shall be 150 by 300mm (6 by 12 in.) or:

100 by 200mm ( 4 by 8 in)

ASTM C31, When casting a 100 x 200 mm (4x8 in) cylinder, the required number of layers of approximately equal depth is:

2

ASTM C1064, Leave the temperature measuring device in the freshly mixed concrete for at least:

2 min

ASTM C143, Complete the entire test from the start of the filling through removal of the mold without interruption and complete it within an elapsed time of:

2-1/2 min

ASTM C31, The temperature initial curing with specified strength greater than 40 mpa(6000 psi) the initial curing temperature shall be:

20 to 26 C (68 to 78 F)

ASTM C231, calculate the air content of a concrete sample based upon the following information: Type B meter is used Aggregate correction factor: 0.8 Reading on the pressure gage: 5.3%

4.5=5.3-0.8

ASTM C172, The tests for slump or air content, or both, must be started within ______ after obtaining the final portion of the composite sample.

5 min

ASTM C138, What is the air content ( in percent) of the following concrete batch?

5.5= (145-137)/145 x 100

ASTM C173, What is the air content( in percent) of the following concrete. sample? Final meter reading:5.5% Amount of alcohol used:2.0 pints

5.5=(5.5-0.2+0)

ASTM C138, Calculate the yield in cubic yards of the following concrete batch: Total mass of all materials batched: 29,850 lb Actual density of the concrete 138 lb/ft

8.0= 29,850/(138x27)

ASTM C138, Upon completion of consolidation, if the concrete is protruding 19mm(3/4 in.) above the top of the measure:

A representative portion of the excess should be removed before strike off

ASTM C143, IN filling and rodding the top later, if the rodding results in subsidence of concrete below the top edge of the mold:

Add additional concrete to keep an excess of concrete above the top of the mold

ASTM C172, To obtain a representative sample from a revolving drum truck mixer, regulate the rate of discharge by:

Adjusting the rate of the revolution of the drum.

ASTM C173, This test method covers determination of the air content of freshly mixed concrete containing:

Any type of aggregate

ASTM C143, If a decided falling away or shearing off of concrete from one side or portion of the mass occurs after lifting the slump test mold:

Disregard the test and make a new test on another portion of the sample.

ASTM C1064, What one of the following statement is true?

Do not remove the temperature measuring device from the concrete when reading the temperature.

According to test method c1064 composite sample are required even if the only purpose for obtaining the sample is to determine temperature. True or False?

False

ASTM C138, The top of the concrete in a measure used in Test Method C138 is struck off with a:

Flat strike-off plate

When the sampling from a paving mixer, Practice C172 permits the composite sample to be obtained:

From five different portions of the pile after the concrete has been discharged.

ASTM C31, After striking off compressive strength specimens, they must be moved to the location of initial storage:

Immediately

ASTM C31, An acceptable way to identify freshly-molded specimens is by:

Marking the side of the mold

According to test method c231/c231m, when the method of consolidation is by vibration:

Never continue vibration long enough to cause escape of froth from the sample.

ASTM C138, The minimum capacity of the measure used for density tests is based upon the:

Nominal maximum size of coarse aggregate in the concrete

ASTM C231, After reading the percentage of air on the pressure gauge in a type B meter, the next step is to release the pressure by:

Opening both petcocks

ASTM C172, When sampling from a stationary mixer, except for a paving mixer, the technician can ensure a representative sample by:

Passing a receptacle completely through the discharge stream.

ASTM C231, Stabilizing the gauge hand of a type B meter at the initial pressure line is accomplished by:

Pumping or bleeding off air as necessary and tapping the gauge lightly.

ASTM C 138, Relative yield is the:

Ratio of the volume of concrete obtained to the volume as designed

Test method C231 is intended for use with concretes and mortars made with:

Relatively dense aggregate only

ASTM C172, Some test procedure require that concrete be sieve prior to testing after removed the large aggregate particle the batch is:

Remixed with a shovel prior to testing.

ASTM C143, When performing a slump test, a concrete sample with 2 in. maximum size aggregate requires which one of the following?

Removal of aggregate over 1-1/2 in. (37.5mm) in accordance with practice C172.

ASTM C173, Immediately after the water and alcohol are added and the watertight cap is tightened, the next step is:

Repeatedly invert and agitate the unit for no more than 5 seconds at a time for a minimum of 45 seconds to free concrete from the measuring bowl.

ASTM C138, When 90 mm(3-1/2 in) slump concrete is consolidated in a 14 L(0.5 ft) measure, consolidation is accomplished by:

Rodding

After rodding and tapping the final layer, test method C173/C173M requires the excess concrete to be struck off with a:

Strike-off bar

ASTM C31, When using light-gauge single-use cylinder molds that are susceptible to denting or other permanent distortion if tapped with a mallet:

Tap the outside of the mold with a open hand

ASTM C143, The slump is measured as the vertical difference between the top of the mold and:

The displaced original center of the top surface of the specimen

ASTM C31, Whether concrete test specimens are field cured or standard cured depends upon

The intended use of the test results

ASTM C31, If the top surface of a test specimens is marred during movement to the place:

The specimens is to be discarded

ASTM C173, After the test, if portions of undisturbed concrete are found in the apparatus after disassembly:

The test is invalid

ASTM C231, If the slump of the concrete is 19mm (3/4 in.) consolidation is accomplished by:

Vibration

ASTM C231, When performing the pressure test using a type B meter, water is injected through one petcock using a rubber syringe until:

Water emerges from the opposite petcock