Deck 25: Masonry Materials-II Concrete Masonry Units, Natural Stone, and Glass Masonry Units

Question 1

The nominal width (through- wall thickness)of a typical CMU is

A)18 in.
B)16 in.
C)12 in.
D)8 in.
E)variable.

Answer 1

E

Question 2

Which of the following CMU shapes has a U- shaped profile in its vertical cross section?

A)Unit with projecting face shells
B)Scored unit
C)Sash unit
D)Bullnose unit
E)Lintel unit

Answer 2

E

Question 3

Arching action occurs in a masonry wall with

A)a running- bond pattern.
B)a stack- bond pattern.
C)both A and B.
D)neither A nor B.

Answer 3

A

Question 4

A typical CMU has

A)five face shells.
B)one face shell.
C)two face shells.
D)four face shells.
E)three face shells.

Question 5

A lintel over an opening in all masonry walls is designed to carry the load from triangle- shaped superimposed masonry.

Question 6

If a CMU wall is vertically reinforced at 16 in. on centers, which of the following units will you recommend for use in the wall?

A)Bond beam unit
B)H- unit
C)Sash unit
D)Standard unit with three webs
E)A- unit

Question 7

Which of the following CMU shapes has a rounded corner?

A)Unit with projecting face shells
B)Lintel
C)Sash unit
D)Bullnose unit
E)Scored unit

Question 8

Which of the following CMU shapes is used to simulate a stack- bond wall, although the wall is, in fact, made with a running- bond pattern?

A)Scored unit
B)Unit with projecting face shells
C)Sash unit
D)Bullnose unit
E)Lintel

Question 9

CMUs with projecting face shells can be used on both sides of a control joint in a wall. The other unit that is commonly used in the same situation is a

A)bullnose unit.
B)sash unit.
C)scored unit.
D)lintel unit.

Question 10

Which of the following CMUs has slotted webs that are broken before being laid in the wall?

A)A- unit
B)Standard unit with three webs
C)H- unit
D)Sash unit
E)Bond beam unit

Question 11

A typical CMU has

A)three webs.
B)five webs.
C)one web.
D)two webs.
E)four webs.

Question 12

A split- face CMU is made by treating a standard CMU with an oxyacetylene torch to produce a very smooth surface on one or more faces of the unit.

Question 13

The voids in CMUs are called

A)voids.
B)cores.
C)frogs.
D)cells.
E)none of the above.

Question 14

If a CMU wall is vertically reinforced at 8 in. on centers, which of the following units will you recommend for use in the wall?

A)Sash unit
B)Bond beam unit
C)Standard unit with three webs
D)H- unit
E)A- unit

Question 15

The center- to- center spacing of vertical reinforcement in a CMU wall cannot be less than 8 in.

Question 16

A burnished CMU is made by treating a standard CMU with an oxyacetylene torch to produce a very smooth surface on one or more faces of the unit.

Question 17

The terms pilaster and pier are synonymous.

Question 18

the nominal height of a typical CMU is

A)18 in.
B)16 in.
C)12 in.
D)8 in.
E)variable.

Question 19

The nominal length of a typical CMU is

A)18 in.
B)16 in.
C)12 in.
D)8 in.
E)variable.

Question 20

If a CMU wall is vertically reinforced at 24 in. on centers, which of the following units will you recommend for use in the wall?

A)Standard unit with three webs
B)H- unit
C)A- unit
D)Both A and B
E)Both A and C

Question 21

Does the term "brick" apply to masonry units made of clay? Explain.

Question 22

Joint reinforcement in CMU walls generally consists of

A)three parallel wires connected together by cross wires.
B)a single wire.
C)two parallel wires without cross wires.
D)two parallel wires connected together by cross wires.
E)none of the above.

Question 23

Out of the three dimensions of commonly used concrete masonry units (CMUs), which two dimensions are standard for all units? Give those dimensions.

Question 24

What is the alternative and more appropriate term for "concrete block"? Is the laying of concrete block a one- hand operation or two- hand operation?

Question 25

Joint reinforcement refers to

A)the horizontal reinforcement in a masonry wall.
B)the vertical reinforcement in a masonry wall.
C)both vertical and horizontal reinforcement in a masonry wall.

Question 26

The grouting of the cells of a CMU wall is required where

A)greater sound insulation of the wall is required.
B)the cells are provided with steel reinforcement.
C)greater fire resistance of the wall is required.
D)all of the above.
E)A and B only.

Question 27

Which of the following stones is generally more vulnerable to disintegration by an acidic atmosphere?

A)Marble
B)Granite

Question 28

Geologically, the earliest rock on the Earth's surface was

A)an igneous rock.
B)a sedimentary rock.
C)a metamorphic rock.
D)none of the above.

Question 29

Slate is

A)an igneous rock.
B)a sedimentary rock.
C)a metamorphic rock.
D)none of the above.

Question 30

The spacing of control joints in a CMU wall

A)is a function of the length- to- height ratio of the wall.
B)should not exceed 25 ft.
C)is a function of the average annual air temperature of the location.
D)B and C.
E)A and B.

Question 31

In general terms, which of the following stones is considered most durable?

A)Slate
B)Marble
C)Granite
D)Limestone
E)Sandstone

Question 32

Marble is

A)an igneous rock.
B)a sedimentary rock.
C)a metamorphic rock.
D)none of the above.

Question 33

Masonry grout has a slump of approximately

A)5 to 6 in.
B)3 to 4 in.
C)4 to 5 in.
D)2 to 3 in.
E)none of the above.

Question 34

Bond beams in a CMU wall can be used to serve the same purpose as joint reinforcement.

Question 35

In a typical CMU wall, face- shell mortaring is used. This implies that the mortar is placed

A)on the horizontal surfaces of the face shells as well as the webs.
B)on the horizontal and vertical surfaces of the face shells.
C)only on the horizontal surfaces of the face shells.
D)on the vertical surfaces of the face shells only.

Question 36

Out of the three dimensions of the commonly used concrete masonry units (CMUs), the length and height dimensions are standard for all units. The through- wall dimension (the width of the unit)is not standard, i.e., the CMU are made in several widths. Name the commonly used widths of CMUs.

Question 37

Some architects and engineers prefer to specify low- lift grouting in masonry walls because

A)it does not require Portland cement.
B)it is more economical.
C)it does not require the use of coarse aggregate.
D)it saves construction time and effort.
E)none of the above.

Question 38

Granite is

A)an igneous rock.
B)a sedimentary rock.
C)a metamorphic rock.
D)none of the above.

Question 39

Masonry grout is a mixture of

A)lime, aggregate, and water.
B)Portland cement, aggregate, and water.
C)Portland cement, lime, and water.
D)Portland cement and water.
E)none of the above.

Question 40

The primary purpose of joint reinforcement in a CMU wall is to

A)increase the compressive strength of the wall.
B)absorb the tensile stress in the wall caused by the expansion of units.
C)absorb the compressive stress in the wall caused by the expansion of units.
D)increase the shear strength of the wall.
E)absorb the tensile stress in the wall caused by the shrinkage of units.

Question 41

In which situation(s)is an A- shape CMU used?

Question 42

CMUs are available as lightweight and normal- weight CMUs. Which one is costlier and which one is preferred by the masons?

Question 43

In extruded clay bricks, the voids are called cores. What are the voids in a CMU called?

Question 44

How many cells are there in a typical CMU?

Question 45

If bond beams are used in place of joint reinforcement for crack control, at what spacing are they provided?

Question 46

What is the purpose of joint reinforcement in CMU walls?

Question 47

What is the shape of a concrete masonry lintel unit?

Question 48

What are the possibilities of center- to- center spacing of reinforcing steel bars (rebars)in CMU walls?

Question 49

What are the typical heights in which CMU lintels are available?

Question 50

In addition to providing joint reinforcement in CMU walls, what additional measure is taken in response to the shrinkage of CMUs?

Question 51

Which bond pattern is typically used in CMU walls?

Question 52

The joint reinforcement for CMU walls is made of longitudinal wires and cross wires. Which of these two wires are embedded in mortar and which are deformed?

Question 53

Give the nominal and actual dimension of the most commonly used CMU.

Question 54

In which situations is a 4 in. (nominal)wide CMU used?

Question 55

What are the typical surface finishes available in CMUs?

Question 56

With reference to a two- cell CMU, give the number of webs and the number of face shells.

Question 57

What is the typical spacing of joint reinforcement in CMU walls?

Question 58

What is the width of a control joint in CMU walls?

Question 59

In which situation(s)is an H- shape CMU used?

Question 60

In constructing a CMU wall, is the mortar placed over the entire bed (horizontal)surface and entire head (vertical)surface of the units? Explain.

Question 61

Explain why granite is the most durable of all building stones. Where would you recommend the use of granite?

Question 62

Which are the most commonly used natural stones in buildings?

Question 63

Explain why CMUs are generally face- shell mortared. In which situations is full- bed mortaring of CMUs used?

Question 64

To which rock (igneous, sedimentary, or metamorphic)do the following stones belong: granite, limestone, marble, and sandstone?

Question 65

Explain the purpose of joint reinforcement in CMU walls. Sketch a typical joint reinforcement used in CMU walls.

Question 66

What is masonry grout and why is it needed?

Question 67

Why is granite the preferred stone for kitchen counter tops?

Question 68

Name the three rocks available on the earth's surface.

Question 69

What is the difference between low- lift grouting and high- lift routing?

Question 70

Explain the differences between lightweight and normal- weight CMUs, including their uses.

Question 71

What measures are used to respond to the shrinkage of CMU walls?

Question 72

With the help of sketches, explain why a running- bond wall has higher horizontal bending strength than a stack- bond wall, whereas the vertical bending strength of both walls is equal.

Question 73

Which type of CMU is used on either side of a control joint in a CMU wall?

Question 74

Explain what arching action in masonry is and its significance in building construction.

Question 75

Two methods are used to pour grout in masonry walls. Name them?

Question 76

Explain the differences between fine grout and coarse grout and where each is used.