Masonry Flashcards
Mortar Ingredients
- Portland cement
- Hydrated lime
- Sand
Type of wall for strength
Serpentine
Pilaster:
Thickened section of masonry wall to support beam to lend strength
Ladder Type and Truss type for masonry reinforcement:
Straight and Zig Zag
Weathered Joint:
Mortar is slanted and comes out towards the bottom
Types of prepackaged mortar
Type M:
a. Has high compression strength, very good for below grade use, foundations, sewers, retention walls. Maintains strength in severe frost, wind, and soil pressure.
Types of prepackaged mortar
Type N:
a. Has medium compression strength for general use above grade, exterior masonry, walls and chimneys
Types of prepackaged mortar
Type S:
a. Has medium to high strength capability recommended where bond and lateral strength are important, such as when flexural bending/moving is required or where mortar is the only
bonding agent.
Types of prepackaged mortar
Type O and K:
a. Mainly low strength for interior use.
What do air entraning admixtures do?
Air entraining admixtures allow the mortar to be high resistant to freeze/thaw cycles.
What do Accelerators do?
Accelerators help dissipate the moisture which in turn reduces freezing.
What does Calcium chloride (liquid form) do?
Calcium chloride prevents the mortar mix from freezing.
Who has set standards for admixtures?
ASTM
Adding sand to mortar does what?
Increases compression strength
Adding lime to mortar does what?
reduces strength but increases flexibility
Plastic mortar properties must be…
wrokable, soft and adhere to masonry units.
Must have good water retention
Mortar should be placed in what temp?
70 - 100 degrees F
Why shouldn’t Retempering (adding water) be done?
Affects water to cement ratio
Plastic mortar should be used within X of being mixed.
2 1/2 hours
Masonry shall be protected from freezing for at least X hours
48 hours
When temperatures exceed X degrees Fahrenheit with winds Y mph or greater, mortar beds shall not exceed Z feet ahead of masonry units.
90 degrees Fahrenheit
8mph or greater
4 feet
Grout is similar to mortar but
has a greater degree of slump
What may grout contain
It may contain pea stone, sand or other approved materials based upon the ASTM standard for a particular use
Where is grout used and why
Grout is used in the cavities of assembled masonry units and cavity walls to add strength.
Desired slump of grout
- Desired slump of grout is between 8” to 10”.
Desired PSI of grout
- PSI should not be less than 2000 PSI.
Plastic grout should be used with X hours of mixing
- Plastic grout should be used within 1 1/2 hours of mixing.
When pouring grout, lifts should not exceed
Lifts (height of fill) should not exceed five (5) feet and shall be vibrated to eliminate voids
Concrete block comes in various sizes and shapes but the most common is
8”, 10”, and 12”.
All are nominal sizes allowing for a X head and bed joint
3/8”
- X 8” x 8” x 16” blocks = Y square feet of wall area.
9
8 square feet
Shapes of CMU’s
Stretchers:
Most common and used for the main wall area
Shapes of CMU’s
Corners:
Have one flush end used at the end of a course
Shapes of CMU’s
Solid top:
Has a solid top for use as a bearing surface
Air space of less than 2” between it is a
Veneer
Air space of greater than 2” between it is a
Cavity
The first course of CMU’s are laid in
the full mortar bed.
Corners (also known as leads) are
laid first, then the area between is filled in.
The use of story pole or course pole is used to
gauge the top of each course.
Use of wire reinforcement, ladder or truss type, can be used in
every other course.
Caution is required when cutting CMU’s due to the
harmful effects of silica dust. Personal protective equipment is required.
When is Face brick (clay masonry units) used?
exposed exterior surfaces where appearance is important.
Generally the face brick is self-supported with
the additional use of brick ties.
Standard face brick measures
- Standard is 3 1/4” x 2 1/4” x 8”.
Face brick must be
approved for the yearly weather conditions
they will encounter. In Michigan the brick needs to be rated for “severe” conditions.
How are Face bricks installed
similar to CMU’s. Corners (leads) are built first and then the area between corners is filled in.
What is required for Face brick installation?
story poles or course poles
What reinforcements are used in installing Face Brick
Brick ties or other reinforcements
Caution in cutting brick is required due to the harmful effects of
Silica Dust
With Face Bricks, X standard brick are required to cover Y square foot of wall area
7 standard brick are required to cover 1 square foot of wall area
Face Brick 6. Mortar joints are X to Y wide
3/8” to 1/2” wide.
What is Efflorescence
Efflorescence is a white powder like substance on completed masonry walls which is caused by water soluble salts within brick and/or mortar coming into contact with moisture (rain, humidity).
How do you get rid of Efflorescence
Eliminate the passage of moisture
Restricted zone size for walls greater than X feet
8 feet
height of wall + 4 feet
MIOSHA Part 2 deals with the rules related to masonry walls exposed to winds. 2. The following are required: a. b. c. d. e. f. g.
a. Training
b. Wall bracing
c. Restricted zones for walls greater than 8 feet
(height of wall + 4 feet)
d. Warning signage
e. Monitoring wind speeds
f. Emergency egress
g. Written certification of employee training
How do you determine bearing wall strip footing dimensions?
The known bearing capacity of the soil determines footing size
How do you determine mat, raft, foundation footing size?
mat, raft, foundation footing covers the entire footprint of structure.
