Chapter 10 Concrete Construction

Question 1

Concrete is the hardened form of _______ produced from Portland cement

Answer 1

Cement

Question 2

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

Answer 2

Aggregates

Question 3

Course aggregates

Fine aggregates

Answer 3

Gravel, stone

Sand

Question 4

Ingredients or chemicals added to concrete with specific characteristics

Answer 4

Admixture

Question 5

Admixture that used to produce a mixture that flows more freely

Answer 5

Superplasticizers

Question 6

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

Answer 6

Fire barriers widely used in type 1 construction

Question 7

Concrete is at one in compression but weaker in

Answer 7

Tension

Question 8

What’s the ultimate compressive strength of concrete

Answer 8

2,500 to 6,000 psi

Question 9

Reinforcing components can include what for concrete

Answer 9

Steel bars ( rebar)
Wire mesh
Fiber glass additives

Question 10

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

Answer 10

Steel bars

Question 11

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

Answer 11

Mechanical vibrators

Question 12

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

Answer 12

Textural shaping of the surface of the bars

Question 13

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

Answer 13

Lateral and tensile support

Question 14

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

Answer 14

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

Question 15

Concrete beams usually cast the shape of a

Answer 15

Tee

Question 16

Vertical reinforcing bars are known as

Answer 16

Stirrups and are provided to resist the diagonal tension

Question 17

To avoid buckling ___________ is provided around the vertical bars

Answer 17

Lateral reinforcing

Question 18

This technique is more efficient use of concrete than ordinary reinforcing

Answer 18

Prestressing

Question 19

Two common types of prestressing

Answer 19

Pretensioning

Post-tensioning

Question 20

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

Answer 20

Rescue a victim

Question 21

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

Answer 21

Pretensioned reinforced concrete

Question 22

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

Answer 22

Post tensioning

Question 23

Prestressed concrete systems may be more vulnerable to failure that

Answer 23

Ordinary reinforced concrete

Question 24

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

Answer 24

Precast concrete

Question 25

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

Answer 25

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

Question 26

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

Answer 26

Corrode and deteriorate

Question 27

Normal design strength is reached after

Answer 27

28 days

Question 28

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

Answer 28

Suitability

Question 29

Single most important factor in determining the ultimate strength of concrete

Answer 29

Water to cement ration

Question 30

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

Answer 30

Desired strength

Question 31

Hardening of concrete involves a chemical process know as

Answer 31

Hydration

Question 32

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

Answer 32

Microscopic gel

Question 33

The moist curing produces a

Answer 33

Stronger concrete

Question 34

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

Answer 34

Between 50-70 degrees. 100 degrees will not reach its proper strength

Question 35

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

Answer 35

Slump test

Question 36

Concrete structural systems can have fire resistance rating of

Answer 36

1-4 hours

Question 37

Structural lightweight concrete is not used for the

Answer 37

Load bearing application

Question 38

Construction technique using concrete slabs supported by concrete columns

Answer 38

Flat slab concrete frame

Question 39

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

Answer 39

Flat plate

Question 40

The primary cause of spalling is the expansion of the

Answer 40

Moisture with in the concrete when heated or frozen

Question 41

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

Answer 41

Heat sink effect

Question 42

Flat slab concrete frame ranges in thickness

Answer 42

6 to 12 inches

Question 43

Frame consists of a concrete slab and supported by concrete beams

Answer 43

Slab and beam framing

Question 44

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

Answer 44

Slab and beam framing

Question 45

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

Answer 45

Slab and beam framing

Question 46

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

Answer 46

Two way slab construction or waffle construction

Question 47

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

Answer 47

Waffle construction or two way framing system

Question 48

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

Answer 48

Precast concrete sandwich panels

Question 49

Precasting concrete became a common practice after

Answer 49

World War II

Question 50

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

Answer 50

Solid slabs Hollow core slab Single tee slabs Double tee slabs

Question 51

Precast concrete solid slab are used for short spans of

Answer 51

Approx 30 feet

Question 52

Tee slabs can be used for spans up to

Answer 52

120 ft

Question 53

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

Answer 53

Tilt up construction Also known as tilt slab construction

Question 54

Supports for precast beams may include

Answer 54

Corbels ( brackets ) cast into the columns