Quality Concrete

Question 1

For concrete to set quickly, Type ___ concrete should be used to produce high early strength

Answer 1

Type III

Question 2

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

Answer 2

High slump, lower strength

Question 3

Which is a characteristic of air-entrainment concrete?

Answer 3

increases workability

Question 4

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

Answer 4

When allowed by the specifier

Question 5

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

Answer 5

mat, raft or floating

Question 6

The maximum delivery time for ready mix concrete is

Answer 6

1.5 hours

Question 7

The safety factor for form tiles is

Answer 7

2:1 ratio

Question 8

What would reduce the lateral pressure on concrete forms?

Answer 8

slower placement

Question 9

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

Answer 9

Tensile forces

Question 10

A #5 bar has what characteristics?

Answer 10

.625” diameter, .31 in2, 1.043 lbs/ft

Question 11

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

Answer 11

Reduce carrying load by 20%

Question 12

What are the most effective types of water stops made of?

Answer 12

PVC polyvinylchloride

Question 13

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

Answer 13

1/4

Question 14

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

Answer 14

4 to 12 hours

Question 15

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

Answer 15

Construction

Question 16

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

Answer 16

2” below the top

Question 17

Welded wire fabric is located where and for what reason?

Answer 17

upper part to prevent cracks

Question 18

To facilitate handling and workability, most specifications will allow the job-site addition of water to the concrete mix to an amount that ____

Answer 18

water to cement ratio is not exceeded

Question 19

To pump through a 5” line, a mix design should consist of a well-graded mix of ____

Answer 19

4” slump with air and fly ash

Question 20

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

Answer 20

become more difficult to pump

Question 21

A vibrator should not remain at one location in the concrete for more than _____ seconds

Answer 21

10-15 seconds

Question 22

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

Answer 22

Blistering

Question 23

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

Answer 23

Broom finish