Chapter 24 Flashcards
The term CMU is generally used as an acronym for?
Concrete mansory unit
The cementitious material(s) in contemporary masonry mortar consist(s) of:
a. Portland Cement
b. Portland cement and sand
c. Portland cement, lime, and sand
d. Portland cement and Lime
e. Lime
d. Portland Cement and Lime
Which of the following materials increases the mortar’s cohesiveness?
a. Mortar joint profile
b. Lime
c. sand
d. All of the above
Lime
What material increases the compressive strength of mortar?
Portland Cement
What material increases the mortar’s workability?
lime
A wall made of Portland Cement mortar (without lime) is more water tight than a wall made of Prtland cement and lime mortar. True or flase?
False
The flexural tensile bond strength of masonry wall is relevant in what situation?
in an unreinforced masonry wall subjected to lateral loads
The flexural tensile bond strength of a masonry wall is a function of: a. the compressive strength of mortar b. the type of masonry units c. the quality of workmanship d, the curing of mortar e. all of the above
all of the above
For a masonry wall, the compressive strength of mortar should be as high as economically feasible. True or false?
False
Masonry mortar types are classified as:
a. Types M, S, N, and O.
b. Types I,II, III, IV
c. either a or b
a. Types M, S, N, and O
The mortar with the highest compressive strength is?
Type M
The mortar most commonly used in an exterior masonry veneer wall is?
Type N
The mortar commonly recommended for use in masonry walls is seismic regions is?
Type S
Mortar may be specified either by proportion specification or by property specification. Which of these two is more commonly used?
a. Proportion specification
b. Property specification
a. Proportion specification
When mortar is specified using proportion specification, various solid materials that constitute masonry mortar are proportioned based on their?
Dry volumes
A preblended cementitious mix for masonry mortar is available as:
a. PCL cement
b. Masonry cement
c. mortar cement
d. a and b
e. b and c
e. b and c
The most commonly used mortar joint thickness is?
3/8in.
Which of the following mortar joint profiles should be specified for an exterior wall?
a. Concave joint
b. Raked joint
c. Flush joint
a. Concave joint
Bricks that have core holes are what kind of bricks
Extruded bricks
Bricks that have frogs are what kind of bricks?
molded bricks
The primary reason for providing core holes in bricks is to:
a. reduce the weight of bricks
b. provide uniform drying and firing of bricks
c. increase the shear resistance of masonry walls
d. none of the above
Provide uniform drying and firing of bricks
The nominal dimension of a masonry unit whose actual dimension equals 7 5/8 in. is:
a. 7in.
b. 7 1/4in.
c. 7 1/2in.
d. 7 3/4in.
e. none of the above
e. none of the above
A masonry unit that has no voids (e.g. no core holes) is referred to as a what type of solid unit?
100% solid unit
A masonry unit that has 20% voids (e.g., 20% core hole area) is referred to as what type of unit?
Solid unit
In specifying the dimensions of a masonry unit, which dimension is stated first?
Width, W, of the unit
In specifying the dimension of a masonry unit, which dimension is stated last?
Length, L, of the unit
Per ASTM standards, facing bricks are classified as Types FBS, FBX, and FBA. Which of these types has the most stringent requirements for dimensional tolerance, chippage, and warpage?
FBX
The freeze- thaw resistance of bricks has been found to be a function of the:
a. compressive strenght of bricks
b. boiling-water absorption of bricks
c. saturation coefficient (SC) of bricks
d. all of the above
D. All of the above
In a running-bond wall:
a. each course consists of headers
b. each course consists of stretchers
c. each consists of alternate headers and stretchers
b. each curse consists of stretchers
The weathering index (WI) of a location is a function of the:
a. Average annual freezing-cycle days
b. average annual winter rainfall of the location
c. average annual air temperature of the location
d. all of the above.
e. a and b
e. a and b
In an English-bond wall:
a. each course consists of headers
b. each course consists of stretchers
c. each course consists of alternate headers and stretchers
d. the courses alternate between headers and stretchers
e. none of the above
d. the courses alternate between headers and stretchers
In a Flemish-bond wall:
a. each course consists of headers
b. each course consists of stretchers
c. each course consists of alternate headers and stretchers
d. the course alternate between headers and stretchers
c. each course consists of alternate headers and stretchers
IRA is a measure of tensile strength of a brick. True and False
False
Bricks that are highly absorptive may need to be wetted before being laid in the wall. True or False
True
Retempering of mortar means?
Adding water to mortar
Retempering of mortar, if needed, should be generally done within:
a. 5 1/2h of the initial preparation of mortar
b. 4 h of the initial preparation of mortar
c. 2 1/2 h of the initial preparation of mortar
d. 1 h of the initial preparation of mortar
e. none of the above
c. 2 1/2 h of the initial preparation of mortar
Efflorescence in masonry refers to:
a. excessive shippage of masonry units
b. excessive warpage of masonry units
c. white spots in masonry walls
d. yellow spots in masonry walls
e. none of the above
c. White spots in masonry walls
