Concrete & Masonry Flashcards
Mortar types
classic mortar:cement, lime (plasticizes, hydrates), sand, water\masonry cement: porland cement + pulverized lime (not as strong)
N: soft stone, ab. grade, ext., 750
S: below grade, better compression, 1800
M: hard stone, load bearing, highest compression, 2500
O: interiors, least strong
putty mortar: for compatibility w historic structures
grout: bonds masonry to reinforcing or fills cavities, has coarse or fine aggregate, up to pea gravel
Brick
burned clay, shale or mix of them
facing (nice finish) vs. building/common
FBS: facing, with a little variation (color/size/texture)
FBX: facing, with not much variation
FBA: facing, but very random
SW: severe weathering
MW:moderate
NW: negligible
hollow brick: HBS, HBX, HBA
sizes: 3 5/8”x2 1/4”x7 5/8”, makes 4x8 when grout jt is 3/8”, from Norman-style brick
wythe = stack
course = horizontal line
bond pattern = how courses relate to each other
horizontal jt = bed jt, vertical jt = bed jt
Brick laying
tool the mortar jt to compress it, make more weatherproof
construction jt/cold jt: isolates masonry from through wall elements like doors, windows
expansion jt: allows for thermal movement, often includes shelf angle and/or compressible joint fillerwhen vertical units need supporting
repointing/tuckpointing: re-mortaring brick
weight is borne at 60 deg angle over top of brick
CMUs
concrete masonry units: hollow (>75%) or solid, load or non-load bearing
wxlxh: h:8/12/16 l/w:4/6/8/10/12 typ:8x8x16 (double a brick course)
needs horizontal reinforcing every 16” o.c.
equivalent thicknesses determined by code for fire ratings (as if no hollow core, eg)
Brick wall types
single wythe, cavity wall, reinforced grouted masonry, veneer
Other masonry types
structural clay tile: burned clay, hollow, load and nonload bearing, only used as backup at exterior walls, not weather proof, good all-in-one structure and finish at interiors, S: select, SS: select sizes (better)
terra cotta tile: ceramic veneer, harder denser, more weatherproof, lighter than stone, adhere or anchor to wall behind, keep water out of non-glazed parts
gypsum block: used for fire protection, old-school
glass block: air inside under vacuum, so insulates well, not fireproof
stone: rubble, slightly squared, ashlar: random or coursed, needs to be anchored to backer w wire/mortar or angle/bolt, can be thinner/veneered stone (adhered only)
<p>Framework</p>
<p>oil/glue/plastic on plywood + wood framing, steel/prefab, FRP, plastic, foam</p>
<p>slip forming: not waiting for complete cure, wait 6-12"/hour, usu for v big jobs</p>
<p>flying forms: reused on floor after floor</p>
<p>insulating (ICEs), polystyrene, remain in place, waterproofing on earth side, gyp on inside, v low acoustical and air flow</p>
<p>costs the most for concrete constr, bc of labor</p>
<p>tolerance: usu .25" out of plumb in 10'</p>
Reinforcement
for req added tensile strength, bars or wire fabric
bar number increases w bar size in 1/8” increments
is deformed to increase bonding
markings indicate grade, source mill, size, type
grades 40/50/60/75 are yield strengths in kips/in2
types: axle, rail, billet
min distance to surface, min dist to each other specified by SE, needs to allow aggregate to pass through
can be reg steel, galv steel, SS, epoxy coated
GFRP: glass fiber reinforced polymer, where no metal can be used, can be used for primary structure
Cement
all is pretty much Portland now = lime (CaOH, CaOx, CaCOx), silica, FeOx, AlOx
type I: normal, type II: modest sulfate resistance, heat controlled (dams), type III: high early strength, type IV: not used, low heat, type V: sulface resisting for high alkaline exposure
excess water creates pores that decrease compressive strength, should be 0.35-0.40 per 1, can create laitance, low strength, chalky pools, must be removed
Aggregates
fines: less than no.4 sieve (4 openings/inch), coarse: 3/4-1”, good to have a variety to air pockets not too large
should be 65-70% of volume
can use clay/shale/slag for lt.wt. concrete, pumice/cinders for insulating concrete
Curing
design strength = compression at 28 days
12,000 psi is high strength, 2000-4000 psi is normal
give it ideal temp/hydration for 7 days-2 weeks (longer if in critical/weird places)
slump test: consistency and water ratio
cylinder test: 7 and 28 day compression test
core cylinder test: taken from structure directly
kelly ball test: ball dropped, measure how much it sinks
impact hammer test: nondestructive hardness test
k-slump: floating scale measures liquidity
CaCl moisture dome test, weighed after 60-72 hrs
hygrometer test/relative humidity
polyethylene sheet test, tape it down, does it bubble?
mat test, same but w pc of impermeable flooring
electrical impedence test: conductance tested
litmus or titration to test for pH, alkalinity is bad for conc, because is dissolves cement, emulsifies adhesives, can avoid by using better aggregates/SCMs
Admixtures
air entraining agent: more workability, more durability bc resists freeze/thaw better, keeps things mixed
accelerator: speeds up hydration reaction, good for cold weather
retarder: slows hydration, lessens heat, good for big pours
waterproofing: reduces water perm
corrosion or shrinkage resistance
superplasticizer: increases workability wo adding water, makes higher strength conc.
SCMs
supplementary cemetitious materials
fly ash: improves workability, from coal furnaces
GGBFs: ground granulated blast furnace slag, is stronger in long run, better to work, durable
silica fume: from silica/metal furnace, reduces permeability
pozzolan: volcanic ash, might be deposited, reduces permeability, increases strength
Special concrete types
autoclave aerated concrete/AAC: precast with Al added, steam cooked, v lightweight, v airtight, but needs waterproofing, not strong
self consolidating concrete/SCC: no vibration needed, superplasticizer used, less labor, and earlier high strength
carbon fiber concrete: expoxy coated carbon fiber mesh instead of steel mesh reinf., thinner, lighter precast panels, less buffer to surface, so stronger despite thinness
ultra high performance/UHPC: high strength, low perm, v durable, 17-25000 psi, cement and silica fume and plasticizer plus alkali resistant glass or steel fibers, usually factory made, often cladding, can be very thin
poured gypsum deck
Finishes
rough: plywood face shows, smooth: from hardboard, metal, smoother wood
form liner: smooth wood, metal, harboard, thin brick
sandblasted, scrubbed, acid wash, water jet: exposes aggregate
brush hammered: looks like meat tenderized
grinding: looks like terrazo
applied: stucco or plaster
smooth rubbed: carborundum abrasive used
grout cleaned: skim coat of grout to even out
strike off: use straight edge to cut
float: bring cement to top w vibration
light steel trowel: done after floating, compacts, smooths
hard steel trowel: even more smooth
superfloat: where wheels need to be fast
broom finish: swept over top to increase grip
stamped: embossed
Concrete joints
control jts: 1/4” depth, saw cut or forms
construction jts: between pours, need waterstops
expansion jts: allows for thermal movement
isolation: prevents vibration conduction
Prestressed concrete
pretensioning: mostly only for precast conc., where tendons are stressed, conc is poured, tension released as hardens, cambers, then load on makes it flat again
post tensioning: pour, stress as it hardens, keep under stress, load
types of cement used in mortar
type I, type II, type III
how long before having to discard mortar
2.5 hours
water table brick
A water table is a projection of lower masonry on the outside of a wall slightly above the ground.It is both a functional and architectural feature that consists of a projection that deflects water running down the face of a building away from lower courses or the foundation.
coping brick
used to protect the wall underneath
jamb bricks
bricks tacked vertically along the opening
difference between grout and concrete
grout is more fluid and pourable
SW grade brick (severe weathering)
used for underground applications and for any climate. tougher brick
MW grade brick (moderate weathering)
weather resistant and exterior only in warm areas
NW grade brick (negligible weathering)
interior use only
headers (bricks)
rotated 90 degrees to tie two wythes of brick together
centering
temporary structure erected to support an arch while being constructed
quoins
corner stones
stone masonry vs stone cladding
masonry is stacked and cladding is attached to building with anchors, skin
ashlar vs rubble
ashlar: rectangularrubble: non rectangular
lewis pins
lift stones
starp anchors
attach the mortar to the wall between courses of stone
concrete block size (common in US)
8x8x16
how do we reinforce concrete block walls horizontally
lay small diameter welded grid steel every few courses for extra load bearing resistance to cracking and sesimic stain
how do we supply vertical reinforcing in concrete masonry
every three blocks, we set rebar and fill the cavities containing the rebar with grout
how do we span over a window or door in concrete masonry
steel lintel, reinforcer block lintel, precast concrete linter
efforescence
white, crystalline deposit of water soluble salts on the surface of the brick masonry
What are the different types of Brick?
- Building Brick: Cored structural bricks, the ones with holes, are for construction. The holes are there to save material and weight.
- Face Brick: These are the sold bricks that face the outside of your building. They are available in various colors, sizes, and shapes.
- Firebrick: This type of brick is heat-resistant and made for fireplace or heat-sensitive construction.
- Brick Pavers: To be used for sidewalks, patios, and edging.
- Antique or Tumbled Brick: Instantly achieve the impression of antiquity with vintage-style brick texture.
- Brick Veneer: Non-load-bearing interlocking brick siding (about 1/2” thick); requires no mortar. These are available for interior or exterior use.
What are the three grades of brick?
The grades of these are:
* Severe Weathering (SW): Able to experience freeze and thaw cycles; perfect for cold climates.
- Moderate Weathering (MW): Tolerance to frost and freezing; used for outdoor walls.
- No Weathering (NW): For indoor use only.
sill bricks
bricks going horizontally along the opening
What are the five types of portland cement according the the American Society for Testing and Materials (ASTM)?
The five types of these include the following
Ordinary (Type I) Modified (Type II) High-early-strength (Type III) Low-heat (Type IV) Sulfate-resistant (Type V)
