Concrete Mix Design

Question 1

What type of concrete is put in place using a pneumatic gun

Answer 1

Shotcrete

Question 2

Where would light weight concrete be used

Answer 2

Masonry concrete and floors in high rise buildings

Question 3

What is soil cement commonly used as

Answer 3

Base for asphalt pavements

Question 4

Tensile strength is approximately what percentage of compressive strength

Answer 4

10%

Question 5

What are mud slabs commonly used for

Answer 5

Work area, Not a structural part of building. (Used as a clean level surface for whatever the fuck u want)

Question 6

Where would heavyweight concrete be used

Answer 6

Shield against X-rays, gamma rays and neutron radiation

Question 7

When can forms be removed if rapid setting concrete is used

Answer 7

4 hours

Question 8

What’s the cylinder test

Answer 8

Measures compressive strength

Question 9

What’s the silt test

Answer 9

Determines presence of very fine clay particles

Question 10

When mixing concrete what part does each number represent 1:2:4

Answer 10

1 part cement
2 parts sand
4 parts course aggregate

Question 11

Colorimetric test

Answer 11

Presence of organic material

Question 12

Calcium chloride is known as a

Answer 12

Set accelerator

Question 13

What is a important quality of effective grout

Answer 13

Does not shrink

Question 14

Difference between mortars and grouts

Answer 14

Mortars are bonders, grouts are fillers

Question 15

What percentage of air should air-entrained concrete contain to be protected from damage by freezing?

Answer 15

5%-8%

Pg. 38

Question 16

In what type of concrete do testing procedures measure flow ability rather then slump

Answer 16

Self consolidating concrete

Question 17

What is a Superplasticizer used for in a concrete mix?

Answer 17

It is used to make a stiff mix flow freely for a short period of time.

Pg. 38

Question 18

Which method of mixing concrete is only for small amounts mixed onsite

Answer 18

Mixing by volume

Question 19

What is the main factor in attaining quality hardened concrete

Answer 19

Water/cement ratio

Question 20

What is an accelerator used for in a concrete mix?

Answer 20

It is used to speed up the setting time and ensures early strength development

Example: calcium chloride

Pg. 38

Question 21

Which of the following will minimize shrinkage in concrete

Answer 21

Proper gradation of aggs

Question 22

Which of the following is considered a concrete additive

Answer 22

Air entrainment

Question 23

What’s are retarders/set inhibitors used for in a concrete mix?

Answer 23

They are used to slow down the setting of the concrete. On hot days or when there are complicated finishes, retards are used.

Pg. 39

Question 24

For standard concrete mix, what is the percentage amount of water used for hydration? 

Answer 24

25%-30%

Question 25

What are the three types of Portland cement that is most common used in the production of concrete?

Answer 25

Types 1,3, and 5 Portland cement

Question 26

Aggregates are the bulk of the material used in concrete mix and account for % to % of the total volume.

Answer 26

60% to 75%

Question 27

Concrete mix is made up of two components, made from four ingredients. What are they?

Answer 27

Cement paste (water & cement)
Aggregates (course and fine).

Question 28

What is the most common slump for slabs?

Answer 28

75mm (3”)

Question 29

What is the most common slump for columns or walls? 

Answer 29

100mm (4”)

Question 30

What two general categories does structural and repair grouts fall into?

Answer 30

Cement and polymeric

Question 31

What grout has very high compressive, tensile, inflexibility strength, and is a two component grout?

Answer 31

Polyester Grout

Question 32

The main difference between concrete and mortars/grouts?

Answer 32

Mortars and grout do not use course aggregates, and a rich mix 

Question 33

What type of cement is used in floors, foundation walls, sidewalks, or high-rise office buildings?

Answer 33

Normal Type 1

Question 34

What type of cement is used where high compressive strength is required fast, such as for columns of high-rise building

Answer 34

Type 3 high early strength, Portland cement 

Question 35

Which type of cement is used for concrete exposed to high concentrations of sulphate in the soil or groundwater 

Answer 35

Type 5 sulphate-resistant Portland cement 

Question 36

Waterproofers increase, which characteristic of concrete?

Answer 36

It’s impermeability

Question 37

Can accelerators be used as antifreeze for cold weather concrete? 

Answer 37

Fak No!