Reinforced Concrete Test 2

1. When approved by the building official; water may be present at the place of deposit when ________.

The concrete is 5000 psi

Footings are being poured in the rain

A tremie is used

The concrete is type III with minimum F’c of 2500 psi

PG. 69, 5.7.1(f)

Explanation

PG. 69, 5.7.1(f)

2. What is the minimum cover (in inches) for reinforcement in concrete cast against and permanently exposed to earth?

2

3

1

1/2

PG. 83, 7.7.1(a)

Explanation

PG. 83, 7.7.1(a)

3. The concrete should be sampled after ________.

All water has been added (adjustment water)

Within 1 hour of the addition of water to the batch

Within 300 drum revolutions on the mixer

Within 30 minutes of arrival at site

The concrete should be sampled after all water has been added (adjustment water) because this ensures that the water-cement ratio is accurate and consistent. Sampling the concrete before all the water has been added may result in an incorrect ratio, leading to poor quality concrete. Additionally, sampling within 1 hour of water addition ensures that the concrete is still fresh and workable. Sampling within 300 drum revolutions on the mixer or within 30 minutes of arrival at the site may not guarantee that all the water has been properly mixed and distributed throughout the concrete mixture.

Explanation

The concrete should be sampled after all water has been added (adjustment water) because this ensures that the water-cement ratio is accurate and consistent. Sampling the concrete before all the water has been added may result in an incorrect ratio, leading to poor quality concrete. Additionally, sampling within 1 hour of water addition ensures that the concrete is still fresh and workable. Sampling within 300 drum revolutions on the mixer or within 30 minutes of arrival at the site may not guarantee that all the water has been properly mixed and distributed throughout the concrete mixture.

4. Concrete represented by cores is acceptable if the average of three cores is _____ percent of F’c and no core falls below ______ percent of F’c.

90, 80

100, 85

100, 75

85, 75

PG. 68, 5.6.5.4

Explanation

PG. 68, 5.6.5.4

5. When rodding the final layer, the rod should penetrate.

1 inch into the first layer

1 inch into the second layer

4 inches

2 inches

ASTM C31, 9.4.1

Explanation

ASTM C31, 9.4.1

6. For six inch cylinders ______ layers should be rodded ______ times each.

4, 50

2, 25

3, 25

2, 20

ASTM C31 Table 3

Explanation

ASTM C31 Table 3

7. The upper most bar rank indicates ______.

Mill

Grade

Steel type

Size

ASTM A615 20.3.1

Explanation

ASTM A615 20.3.1

8. Partially embedded reinforcement may be field bent when _______.

Preheating is used

Necessary for adjacent work

Shown on design drawings

Minimum bend diameters are maintained

PG. 80, 7.3.2

Explanation

PG. 80, 7.3.2

9. When assembling rebar, crossing bars should not be _______.

Welded

Held with plastic clips

Galvanized tie wire

Stainless steel tie wire

PG. 82, 7.5.4

Explanation

PG. 82, 7.5.4

10. Initial curing temperature for cylinders is ____ degrees Fahrenheit.

Between 60 and 80

50 - 90

70 - 90

70 – 76

ASTM C31, 10.1.2

Explanation

ASTM C31, 10.1.2

11. Precautions for cold weather concrete should be followed when the mean daily temperature falls to ______degrees Fahrenheit.

32

40

45

50

ACI 306

Explanation

ACI 306

12. For bundled bars, minimum concrete cover shall be equal to the equivalent diameter of the bundle, but need not be greater than ____ in.; except for concrete cast against and permanently exposed to earth, where minimum cover shall be 3 inches.

2

1

3/4

3

PG. 85, 7.7.4

Explanation

PG. 85, 7.7.4

13. Cylinders being transported to the lab should be _______.

Cushioned

Upright and braced

Horizontal and stacked

60 – 80

ASTM C31, 11.1

Explanation

ASTM C31, 11.1

14. Steel for welded reinforcing is best described by ASTM ________.

A615

A128

A480

A706

ASTM A706, 1.1

Explanation

ASTM A706, 1.1

15. What is the minimum cover (in inches) for primary reinforcement in a concrete beam not exposed to weather or in contact with the ground?

1 ½

2

1

3/4

PG. 84, 7.7.1(c)

Explanation

PG. 84, 7.7.1(c)

16. During a 400 yard placement, ______ samples for strength tests are required.

2

3

4

8

PG. 65, 5.6.2.1

Explanation

PG. 65, 5.6.2.1

17. Final curing temperature for cylinders is ____ degrees Fahrenheit.

70 - 75

73 +/- 6

73 +/- 3

60 – 80

ASTM C31, 10.1.3.1

Explanation

ASTM C31, 10.1.3.1

18. According to the building code, the minimum depth of footings (except category R-3) is ________ inches.

6

8

10

12

IBC 1805.2

Explanation

IBC 1805.2

19. The tolerance on a specified 3 inch slump when the project specifications are not written as “maximum” or “not to exceed” requirement is _______ inch(es).

+/- 1/2

+/- 1

+/- 1 1/2

+/- 2 1/2

ASTM C94, 7.1.2

Explanation

ASTM C94, 7.1.2

20. Concrete shall be thoroughly consolidated by ______.

Internal vibration

External vibration

Suitable means

When reinforcement spacing exceeds 6db

PG. 70, 5.10.8

Explanation

PG. 70, 5.10.8

21. Seismic hooks with a 135 degree bend require a minimum extension of _____db but not less than _____ inches.

12, 2

6, 3

8, 3

6, 2

PG. 79, 7.1.3(c), PG. 306

Explanation

PG. 79, 7.1.3(c), PG. 306

22. Concrete samples may only be rodded when the slump is greater than ______ inches.

4

2

3

1

ASTM Table 2

Explanation

ASTM Table 2

23. A strength test shall be the average of ______ tests.

4

3

2

6

PG. 65, 5.6.2.4

Explanation

PG. 65, 5.6.2.4

24. At footings, the splice between a #14 bar and a #18 bar in compression should be _______.

Not allowed

Lap splice

Mechanical connection

Welded

PG. 248, 15.8.2.3

Explanation

PG. 248, 15.8.2.3

25. In hot weather consideration of _______ is least important.

Schedule

Application of curing compound

Fog sprayers and wind curtains

Wetting the coarse aggregate stockpile

In hot weather, wetting the coarse aggregate stockpile is least important because hot weather conditions already provide enough heat for the aggregate to dry quickly. Wetting the coarse aggregate stockpile is typically done to prevent excessive evaporation and to maintain the desired moisture content in the concrete mixture. However, in hot weather, the heat can cause the water to evaporate rapidly, making it less effective to wet the coarse aggregate stockpile. Therefore, in hot weather, other considerations such as scheduling, application of curing compound, and the use of fog sprayers and wind curtains become more important to ensure proper curing and prevent premature drying of the concrete.

Explanation

In hot weather, wetting the coarse aggregate stockpile is least important because hot weather conditions already provide enough heat for the aggregate to dry quickly. Wetting the coarse aggregate stockpile is typically done to prevent excessive evaporation and to maintain the desired moisture content in the concrete mixture. However, in hot weather, the heat can cause the water to evaporate rapidly, making it less effective to wet the coarse aggregate stockpile. Therefore, in hot weather, other considerations such as scheduling, application of curing compound, and the use of fog sprayers and wind curtains become more important to ensure proper curing and prevent premature drying of the concrete.

26. Strength tests of field cured cylinders do not _____.

Indicate deficiencies in protection and curing

Form the basis for acceptance or rejection of F’c

Allow for guidance for shoring and reshoring

Determine removal times for forms

Strength tests of field cured cylinders do not allow for guidance for shoring and reshoring. This means that these tests cannot provide information or recommendations on the appropriate methods or timing for supporting or removing the forms used in construction. Instead, they primarily focus on assessing the strength of the concrete after it has cured in the field. The tests help to determine if the concrete meets the required strength criteria for acceptance or rejection, as well as identify any deficiencies in protection and curing.

Explanation

Strength tests of field cured cylinders do not allow for guidance for shoring and reshoring. This means that these tests cannot provide information or recommendations on the appropriate methods or timing for supporting or removing the forms used in construction. Instead, they primarily focus on assessing the strength of the concrete after it has cured in the field. The tests help to determine if the concrete meets the required strength criteria for acceptance or rejection, as well as identify any deficiencies in protection and curing.