Quality Concrete

Question 1

For concrete to set quickly, Type ________ concrete should be used to produce high early strenght?

Answer 1

17. Type III.

Question 2

What is the result of too much water in a concrete mix?

Answer 2

18. Higher Slump & Lower Strength

Question 3

Which is a characteristic of air-entrainment concrete?

Answer 3

21. Increases Workability.

Question 4

When can fly ash be used in the calculation of minimum cement content for a concrete mix?

Answer 4

29. When allowed by specifier.

Question 5

Which type of foundation would generally be specified when the allowable bearing capacity of the soil is very low to great depths?

Answer 5

36. Mat, Raft, or Floating

Question 6

The maximum deliver time for ready-mix concrete is _______?

Answer 6

30. 1.5 hours.

Question 7

What would reduce the lateral pressure of concrete forms?

Answer 7

54. Slower Placement.

Question 8

The main purpose for steel reinforcement is to resist what type of force?

Answer 8

63. Tension Forces.

Question 9

A #5 bar has what characteristics?

Answer 9

66. 5/8” or .625 Diameter ; 0.31in2 ; 1.043 lbs/ft.

Question 10

What is theeffect of lowering the top bar or raising the lower bar by 1/2” more than specified in a 6” slab?

Answer 10

73. Reduces carrying load by 20%.

Question 11

Control joint cuts in a slab should be to a depth of ________ the slab thickness?

Answer 11

88. 1/4(th).

Question 12

Within how many hours after placement should concrete joints be sawn?

Answer 12

89. 4-12(hours).

Question 13

Which type of joint is used to control cracks where placement of concrete is interrupted?

Answer 13

90. Construction Joints.

Question 14

In a mat slab, generally, where below the top is the steel located?

Answer 14

92. 2” Below the top.

Question 15

Welded wire fabric is located where below the top is the steel located?

Answer 15

92. Upper part to prevent cracks from opening.

Question 16

If lightweight aggregate to be pumped is not presoaked so that it consistently contains 70-80 percent of total absorption, the aggregate may?

Answer 16

124. Makes pumping more difficult.

Question 17

A vibrator shoudl not remain at one location in the concrete for more than ______ seconds?

Answer 17

124. 10-15(seconds).

Question 18

Air entrainment increases the probability of which type of concrete field problems?

Answer 18

138. Blistering.

Question 19

A non-slip surface on the concrete is obtained by what means?

Answer 19

127. Broom Finish.