Mixture

water

cement

aggregates

fine aggregates

coarse aggregates

admixtures

Mixing:

transit-mixed

mixing drum

surface mixed with shovel

1 shovel cement (94-lb. bag)

2 shovels of sand

3 shovels of gravel

enough water to mix it

Slump test

cone

12" tall

6" top

12" bottom

5/8" 24" long taping rod

slump measured in inches

7-day break

standard test cylinder

60 - 70% of final strength

up to 90% with high-earlystrength

Portland cement III & admixtures

28-day break

final strength

test cylinder

6"

12" high

Strength

w/c ratio - the less water the better

balanced aggregates

cement type, admixtures, curing

Wet Concrete:

slurry - not liquid

segregates

vibrated excessively

aggregated

dropped > 3'

dropchutes

moved horizontal

pumped

conveyed

workability

admixtures

Compacted:

Thrusting rode or spade

immersion-type vibrator

Striking off

level

Preliminary smoothening

bull float

Floating

plane surface

cement paste to surface

hand

machine

Steel Troweling

dense

hard

smooth surface

Curing Process

Hydration

chemical reaction

slow

28 days - 98% of strength

reaction stops when dry

moist cured

25 % strength increase

after 28 days

over air-dried

which stops completely

Protection

Proper Form

wood absorbs water

Remain formed-in

Moist top surface

fogging with water- after pour

spraying with water

flooding with water

curing compound - seal surface

cover with plastic foil

Temporary Windbreaks

Shades

Temperature

Cold

reduced curing

Freezing

curing stops

cover concrete

heat of hydration keeps it warm

heated admixture

temporary enclosure

insulation blankets

temporary heat source

Hot

accelerated hydration

cured before placed and finished

cool incidents

ice instead of water

liquid nitrogen

Concrete Ingredients:

Coarse aggregates

aggregate selection

Fine aggregates

scrubbing

hosing off

cement paste

pre treat forms to retard cement

Color

Form:

plywood - grain pattern

smooth

sandblasted

wirebrushed

sheathing lumber

board texture

formliners

metal

plastic

Treatment after set:

Color

painted

dyed

Smooth

rubbed

ground smooth

Textured

sandblasted

wirebrushed

Coarse Texture

bush hammered

jack hammered

Drill

rotary hammer

wholes 1/8" - 1"

carbide/diamond drill

core sample

plumbing

Saw

diamond chainsaw

flex-grinder

square cuts

openings

expansion joints

hand held

water-cooled motorized

level concrete

Wire Brush

Jack-Hammer

pneumatic

electric

gravity - large

larger openings

demolition

surface texture

drill bit

chisel bit

Chisel

manual

stone carving

Bush Hammer

manual

Blasting

dynamite

thaw-freeze cycles

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LECTURES

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Timetable

Prof. Dr. Hermann Gruenwald

(mail comments to: HGRUENWALD@ou.edu)

College of Architecture

The University of Oklahoma