Chapter 10 Concrete Construction Flashcards

1
Q

Concrete is the hardened form of _______ produced from Portland cement

A

Cement

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2
Q

Inert mineral ingredients that reduce the amount of cement that would otherwise be needed

A

Aggregates

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3
Q

Course aggregates

Fine aggregates

A

Gravel, stone

Sand

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4
Q

Ingredients or chemicals added to concrete with specific characteristics

A

Admixture

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5
Q

Admixture that used to produce a mixture that flows more freely

A

Superplasticizers

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6
Q

Concrete structure elements usually retain their integrity and concrete slabs and walls act as good

A

Fire barriers widely used in type 1 construction

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7
Q

Concrete is at one in compression but weaker in

A

Tension

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8
Q

What’s the ultimate compressive strength of concrete

A

2,500 to 6,000 psi

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9
Q

Reinforcing components can include what for concrete

A

Steel bars ( rebar)
Wire mesh
Fiber glass additives

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10
Q

Ordinary reinforcing uses ________ placed in the framework and wet concrete placed in the framework

A

Steel bars

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11
Q

Used to ensure that the wet concrete fills all the spaces within the framework

A

Mechanical vibrators

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12
Q

When concrete is hardened it adheres to the reinforcing bars because of what

A

Textural shaping of the surface of the bars

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13
Q

Reinforcing concrete uses a planned grid of structural reinforcing materials to provide

A

Lateral and tensile support

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14
Q

Are commonly referred to by a standardized number instead of the actual diameter

A

Rebar sizes
Largest size is #18
Most common size #5

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15
Q

Concrete beams usually cast the shape of a

A

Tee

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16
Q

Vertical reinforcing bars are known as

A

Stirrups and are provided to resist the diagonal tension

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17
Q

To avoid buckling ___________ is provided around the vertical bars

A

Lateral reinforcing

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18
Q

This technique is more efficient use of concrete than ordinary reinforcing

A

Prestressing

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19
Q

Two common types of prestressing

A

Pretensioning

Post-tensioning

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20
Q

Reid forces steel should not be cut durning firefighting operations unless to

A

Rescue a victim

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21
Q

Uses steel strands (cables) stretched between anchors producing a tensile force in the steal concrete

A

Pretensioned reinforced concrete

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22
Q

Uses reinforcing steel cables that are not tensioned until after the concrete has hardened

A

Post tensioning

23
Q

Prestressed concrete systems may be more vulnerable to failure that

A

Ordinary reinforced concrete

24
Q

Placed in a form and cured at a plant away from the job site

A

Precast concrete

25
Q

Placed into forms at the building site as a wet mass and hardens in prepare forms

A

Cast in place concrete usually stronger that precast because of continuity in intersecting members

26
Q

Using sand from the beach in concrete over time cans _________ and ________ overtime to the reinforcing steel

A

Corrode and deteriorate

27
Q

Normal design strength is reached after

A

28 days

28
Q

The quality of concrete must be tested to ensure the ____________ of the mixture for the purpose

A

Suitability

29
Q

Single most important factor in determining the ultimate strength of concrete

A

Water to cement ration

30
Q

If too much too much water has been used in the mix the final product will not achieve its

A

Desired strength

31
Q

Hardening of concrete involves a chemical process know as

A

Hydration

32
Q

Water combines with the particles of of cement to form _________ this gel releases heat of hydration

A

Microscopic gel

33
Q

The moist curing produces a

A

Stronger concrete

34
Q

Concrete in the process of curing mist be maintains in the correct temp

A

Between 50-70 degrees.

100 degrees will not reach its proper strength

35
Q

Method of evaluating the moisture content of wet concrete by measuring the amount that small cone shaped sample when removed from a standard sized test mold

A

Slump test

36
Q

Concrete structural systems can have fire resistance rating of

A

1-4 hours

37
Q

Structural lightweight concrete is not used for the

A

Load bearing application

38
Q

Construction technique using concrete slabs supported by concrete columns

A

Flat slab concrete frame

39
Q

Plain floor slab about 8 inches thick that rests on columns spaced up to 22 feet

A

Flat plate

40
Q

The primary cause of spalling is the expansion of the

A

Moisture with in the concrete when heated or frozen

41
Q

Concrete tends to retain the heat of an exposing fire then releases heat slowly

A

Heat sink effect

42
Q

Flat slab concrete frame ranges in thickness

A

6 to 12 inches

43
Q

Frame consists of a concrete slab and supported by concrete beams

A

Slab and beam framing

44
Q

This framing system is extremely lightweight and is best suited for buildings with light floor loads

A

Slab and beam framing

45
Q

Concrete beams run mainly in one direction - one way reinforced slab

Sometimes referred to joist construction - similar to wood framing

Slab could be as thin as 2 inches

A

Slab and beam framing

46
Q

Slab and beam concrete framing featuring concrete beams tuning in two directions is known as

A

Two way slab construction or waffle construction

47
Q

This construction is used where spans are short and flood loads are high

A

Waffle construction or two way framing system

48
Q

Can be produced using polystyrene core to improve the insulating properties of the precast concrete

A

Precast concrete sandwich panels

49
Q

Precasting concrete became a common practice after

A

World War II

50
Q

Precast concrete slabs for floor systems I’m standard shapes of

A

Solid slabs
Hollow core slab
Single tee slabs
Double tee slabs

51
Q

Precast concrete solid slab are used for short spans of

A

Approx 30 feet

52
Q

Tee slabs can be used for spans up to

A

120 ft

53
Q

Type of construction in which concrete wall sections (slabs) are cast on the concrete floor of a building then tilted up to vertical position

A

Tilt up construction

Also known as tilt slab construction

54
Q

Supports for precast beams may include

A

Corbels ( brackets ) cast into the columns