Ch.10

Question 1

__________ is the hardened form of cement produced from Portland cement, coarse and fine aggregates and water ?

Answer 1

Concrete

Question 2

____________ make up a large percentage of the total volume of concrete?

Answer 2

Aggregates

Question 3

__________ can help tailor a batch of concrete for specific functions ?

Answer 3

Admixtures

Question 4

Admixture that reduces the density of the concrete?

Answer 4

Shake or clinker

Question 5

Admixture that produces a mixture that flows more freely , makes concrete workable , pliable and soft while using relatively little water?

Answer 5

Superplasticizers

Question 6

Like masonry , concrete is strong in compression but weaker in tension , the ultimate compressive strength can range from ______. To ______psi?

Answer 6

2500 to 6000 psi

Question 7

_______________ includes components added to the concrete before it hardens to resist tensile forces?

Answer 7

Reinforced concrete

Question 8

_____________ uses steel bars placed in the framework , and wet concrete is placed in the framework around the bars?

Answer 8

Ordinary reinforcing

Question 9

The most commonly used size of rebar is _____?

Answer 9

5 (0.625inches)

Question 10

Vertical reinforcing bars are known as _________ and are provided to resist the diagonal tension ?

Answer 10

Stirrups

Question 11

The technique of ___________ is a more efficient use of concrete than ordinary reinforcing?

Answer 11

Prestressing

Question 12

Two common methods of prestressing concrete are ?

Answer 12

Pretensioning
Post tensioning

Question 13

____________________ uses steel strands (cables) stretched between anchors producing a tensile force in the steel?

Answer 13

Pretensioned reinforced concrete

Question 14

________________ uses reinforcing steel cables that are not tensioned until after the concrete has hardened to a certain strength?

Answer 14

Post tensioned reinforcement concrete

Question 15

_________ is placed in forms and cured at a plant away from the job site?

Answer 15

Precast concrete

Question 16

_____________ is placed into forms at the building site as a wet mass and hardens in prepared forms ?

Answer 16

Cast in place concrete

Question 17

The systems use reinforcing cable and rods made of high strength steels that can yield at temperatures as low as _____ ?

Answer 17

752 degrees F

Question 18

Reinforcing strands are placed in a form work and covered with ________ or __________ to prevent binding with the concrete?

Answer 18

Grease or plastic tubing

Question 19

Theoretically ,properly cured concrete continues to harden indefinitely at a gradual rate , normal design strength is reached after _____ days?

Answer 19

28 days

Question 20

The single most important factor in determining the ultimate strength of concrete is the ______________?

Answer 20

Water to cement ratio

Question 21

Hardening of concrete involves a chemical process known as _____________ , in which water combines with the particles of cement to form a microscopic gel?

Answer 21

Hydration

Question 22

During the hardening of concrete , heat is given off by the chemical process?

Answer 22

Heat of hydration

Question 23

The _______ curing of concrete produces a stronger concrete?

Answer 23

Moist

Question 24

Concrete in the process of curing must be maintained at the correct temperature, ideally between ___ and ___ degrees ?

Answer 24

50 to 70 degrees F

Question 25

The _________ uses a standard sized cone shaped mold and sample of wet concrete?

Answer 25

Slump test

Question 26

__________ testing is a separate test that uses a small test cylinders of a concrete batch to determine the compression strength of that batch?

Answer 26

Compression

Question 27

Concrete structural systems can have fire resistance rating from __ to __ hours ?

Answer 27

1-4 hours

Question 28

________________ concrete has a lower density than ordinary concrete and has a lower thermal conductivity, and therefor acts as a better insulator against the heat of a fire than ordinary concrete of comparable thickness?

Answer 28

Structural lightweight

Question 29

Construction technique using concrete slabs supported by concrete columns ?

Answer 29

Flat slab concrete frame

Question 30

Plain floor slab about 8 inches thick that rests on columns spaced up to 22 feet apart and depends on diagonal and orthogonal patterns of reinforcing bars for structural support because the slab lacks beams?

Answer 30

Flat plate

Question 31

Because concrete has relatively good insulating properties, it tends to retain the heat of an exposing fire and release it slowly , in an effect referred to as the ?

Answer 31

Heat sink effect

Question 32

The ____________ is a simple system that consists of a concrete slab with concrete columns for support , the slab of concrete ranges in thickness from 6 to 12 inches ?

Answer 32

Flat slab concrete frame

Question 33

In a building that will support heavy live loads , the area around the columns is reinforced with additional concrete in the form of ____________ or __________?

Answer 33

Drop panels or mushroom capitols

Question 34

If the building will support light loads , this additional reinforcing is not necessary, the system is then known as a _____________?

Answer 34

Flat plate

Question 35

A _____________ consists of a concrete slab supported by concrete beams, this framing system is extremely lightweight and is best suited for buildings with light floor loads ?

Answer 35

Slab and beam frame

Question 36

Slabs in slab and beam framing construction can be as thin as __ inches ?

Answer 36

2 inches

Question 37

Slab and beam framing is sometimes referred to as _________________ construction?

Answer 37

Concrete joist construction

Question 38

________________ construction is known as waffle construction because of the waffle like pattern of the bottom of the concrete slab?

Answer 38

Two way slab

Question 39

This design provides a thicker slab while eliminating the weight of unnecessary concrete in the bottom half of the slab?

Answer 39

Waffle construction

Question 40

Waffle construction is used where spans are _____ and floor loadings are _____?

Answer 40

Short and high

Question 41

Precasting concrete became a common practice after ________?

Answer 41

World War II

Question 42

A major disadvantage to using __________ is the need to transport the finished components to the job site?

Answer 42

Pre cast concrete

Question 43

Pre cast concrete solid slabs are used for short spans up to approximately ____ feet while the Tee slabs can be used for spans up to ____ feet?

Answer 43

30 feet 120 feet

Question 44

___________ is a common form of construction used with precast concrete ?

Answer 44

Tilt up construction

Question 45

________ walls can be several stories in height?

Answer 45

Tilt up

Question 46

A variety of techniques, such as ________,________ and ______________ can be used to connect precast structural components to each other?

Answer 46

Bolting Welding Posttensioning

Question 47

Supports for precast beams may include __________ cast into the columns ?

Answer 47

Corbels (brackets)