Masonry Flashcards
What do construction joints in masonry do?
Isolate the masonry from the through wall elements such as doors and windows.
Control joints in masonry accommodate _______ and ______.
Thermal expansion and contraction.
The slope of coping on top of a brick wall is called…
wash
What is efflorescence?
A white, crystalline deposit from water-soluble salts on the surface of brick. It is caused when water seeps into the masonry and then evaporates leaving behind salts.
What is the equivalent block thickness of an 8” thick concrete block that is 60% solids?
Actual thickness is 7 5/8” (7.625) (7.625)(.60) = 4.58
Major Expansion joints are placed every ________ to ________ feet in large buildings?
100’ to 150’
Expansion and control joints are placed where in brick masonry walls?
Every 20’ and wherever a wall changes direction height of thickness
Horizontal expansion joints should be placed where?
below shelf angles that support the intermediate sections of brick below beams and slabs of brick
With Single wythe walls what is the maximum ratio of unsupported height or length to thickness cannot exceed?
20:1 in solid masonry walls 18:1 in hollow masonry
What is the spacing of horizontal reinforcement in both CMU and brick masonry walls?
16” on center
what are the 8 types of tooling in masonry construction?
concave, vee, flush, trowel struck, extruded, beaded, raked, weather struck
What is the slope of the coping called?
The wash
What is the typical spacing for weep holes?
24” on center
What type of cement would be best when tuck pointing a masonry wall?
High lime cement
What is mortar made of?
Portland Cement, hydrated lime, and an inert aggregate (sand)
What type of mortar would be best in an exterior load bearing application?
Type M and S
After what amount of time should masonry that was mixed be discarded?
2.5 Hours after it was mixed, because at this point the masonry has begun the chemical process
What are the three grades of building brick?
SW (Oregon and Eastern coast of US) MW (Midwest most of Washington) NW (Southern US, New Mexico Oklahoma Texas)
What are the three grades of facing brick
FBX- Best FBS- Middle FBA- Lowest
What are the average thickness for mortar joints?
1/4”-1/2”
How long after masonry is placed should the wall be struck?
1-2 hours
What are the 4 types of masonry joints that are good in exterior applications?
Weathered Joint Concave Joint Vee Joint Flush Joint
What is the ideal temperature range for laying brick?
40 degrees - 90 degrees
T/F Brick should be wetted before setting to minimize water absorption.
TRUE
Why is aluminum not used in flashing applications?
Because the chemical reaction that occurs between mortar and aluminum can disintegrate.
What is the minimum clear airspace for a masonry wall?
2” while sometimes less with a rainscreen
what is the ideal water to cement ratio?
.45-.50 avg. .35-.40 min.
Fine aggregates are those that pass through a _______ seive?
number 4
What are the aggregates in lightweight concrete?
Expanded clays, slags, and shales
What are the aggregates in insulating concrete?
pumice, or cinders
What are 6 different types of add mixtures that can be added to concrete?
Air entraining agents Accelerators Plasticizers Retarders Waterproofing Fly Ash
Why would fly ash be specified as an addmixture in concrete?
It is a sustainable material left over from the coal burning process that increases the strength, decreases permeability, reduces temperature rise, increases sulfate resistance, and improves work-ability. It can also decrease the amount of cement required.
How thick is the carbon fiber grid, in carbon fiber concrete, and how much stronger is it than steel mesh?
0.04 in thick and 7 times stronger
How much strength does concrete gain after its first week of curing?
70% of its strength
How much strength can concrete lose when it freezes while curing?
0.5
How far can a typical 4’ wide, by 12” deep concrete core slab extend?
36’
What is the architectural concrete finish called where shaped with liners of plastic wood or metal. Parallel rib liners are a common type. Joints and form tie holes are treated as desired either left exposed or patched.
Form Liner
What is the architectural concrete finish called where the surface of the concrete is wetted and scrubbed with a wire or fiberbrush to remove some of the surface mortar and expose the coarse aggregate?
Scrubbed
What is the architectural concrete finish called where the surface of the concrete is wetted with muriatic acid to expose and bring out the full color of the aggregate?
Acid Wash
What is the architectural concrete finish called where a high pressure water jet mixed with air is used to remove some of the mortar and expose the aggregate
Water Jet
What is the architectural concrete finish called where you have a rugged heavy texture by removing a portion of the surface made with form liners. The type of texture depends on the liner
Bush Hammering
What is the architectural concrete finish called where finishes include the application of other materials such as stucco or concrete?
Applied
What is the architectural concrete finish called that is produced by removing surface material from the concrete exposing the aggregate to varying degrees as specified by light medium or heavy.
Sand Blasted
What is the architectural concrete finish called where the surface of the concrete is wetted and rubbed with a carborundum brick to produce a smooth uniform color and texture?
Smooth
What is the architectural concrete finish called where grout is applied over the concrete and smoothed out to make the appearance uniform and conceal defects?
Grout cleaned
How many days does it take for high early strength concrete to reach its 28 day strength?>
7-14 days
What does the A represent in Type IA, Type IIA, Type IIIA cement?
Air Entraining
What are the advantages for Air Entraining concrete?
Great for cold climates, and pavings, increases workability, and increases concretes resistance to freeze thaw cycles
How do you size aggregate in concrete?
Aggregate should not be larger than 3/4 the size of the spacing of the rebar. or larger than 1/3 the depth of the slab
What are the advantages of plasticizers?
Greater workability and they increase the strength of the concrete by reducing the concretes need for water.
What is silica fume?
The byproduct of computer manufacturing it has EXTREMELY HIGH strength and low permeability
What are the advantages of silica fume in concrete?
Increased compression strength Increased modulus of elasticity Increased durability Increased permeability
What is a pozzolan?
A varicose natural/artificial material with similar properties to cement
What is a fibrous admixture?
glass or steel fibers that when added to concrete increase its flexural stress.
T/F High water to cement ratios decrease the strength of concrete.
TRUE
In rebar what does the S or W mean?
S - Carbon steel W - Low alloy steel
