Amber Book Concrete

Question 1

What is the drying (curing) time of concrete?

Answer 1

28 days

Question 2

What is type 1a cement?

Answer 2

normal concrete that is air entrained with bubbles that help with durability/workability. can be exposed in cold and mixed climates

Question 3

What is type 2 cement?

Answer 3

moderate resistance to sulfate that can attach concrete and weaken it. USE BELOW GRADE

Question 4

What is type 2a cement?

Answer 4

sulfates and air entrained

Question 5

What is type 3 cement?

Answer 5

high early strength cement used for PRECAST, TILT UP to save time. also cold weather

Question 6

What is type 3a cement?

Answer 6

high early strength with air entrained

Question 7

What is type 4 cement?

Answer 7

low heat of hydration. used in MASSIVE INFRASTRUCTURES.

Question 8

What is type 5 cement?

Answer 8

high resistance to sulfate

Question 9

What is white portland cement?

Answer 9

used for countertops

Question 10

What is aggregate size?

Answer 10

no greater than 3/4 between rebar and 1/3 depth of slab

Question 11

How do you make pervious concrete?

Answer 11

use aggregates of the same size

Question 12

What do lightweight aggregates do?

Answer 12

they make concrete lighter and more thermally resistant, but also weaker. POPCORN expanded shale

Question 13

What is vermiculite?

Answer 13

expanded mica that is a lightweight aggregate

Question 14

What is perlite?

Answer 14

expanded volcanic rock that is a lightweight aggregate

Question 15

What does adding water to concrete do?

Answer 15

more workable but less strong

Question 16

What is ultra high strength concrete made of?

Answer 16

silica, quartz, steel microfibers (NO REBAR)

Question 17

What do shrinkage reducing admixtures do?

Answer 17

reduce cracking

Question 18

What are corrosion inhibitors?

Answer 18

they reduce rusting of rebar on pavers like on parking garages or salt on the road

Question 19

What does extended set control do?

Answer 19

delays curing for up to several days. stabilizer added when mixing which puts off until activator is added

Question 20

What is self consolidating concrete?

Answer 20

doesn’t need vibrators. used for when rebar is croweded in the formwork. Has crisp edges. more pourable but also more pressure on formwork

Question 21

How do you protect rebar from saltwater?

Answer 21

coat with epoxy, galvanize, stainless steel, or zinc polymers

Question 22

Where do you put welded wire reinforcing? What is the spacing?

Answer 22

in the bottom of slabs. WWR. 2” min to 12” max grid

Question 23

What length do you overlap/splice rebar?

Answer 23

30 x diameter

Question 24

What is a reinforcing bar coupler?

Answer 24

a rebar combiner that puts the rebar end to end

Question 25

What is shrinkage temperature steel?

Answer 25

steel perpendicular to rebar in a slab to prevent shrinkage in slabs

Question 26

What do concrete ties do?

Answer 26

in columns, they prevent outward buckling. Can be rectilinear or spiral. Spiral is better for earthquakes.

Question 27

What do micro and macrofibers do?

Answer 27

they help with shrinkage and less cracking; may replace shrinkage temperature steel

Question 28

What is creep?

Answer 28

the squishing of concrete over time.

Question 29

How thick is slab on grade?

Answer 29

3" to 8"

Question 30

What diameter crushed stone to place under slab on grade?

Answer 30

1 1/2" diameter crushed stone for capilary break

Question 31

What is screeding?

Answer 31

push and pull excess concrete over the formwork for leveling

Question 32

What is floating?

Answer 32

with bull float or darby to make concrete flat

Question 33

What is troweling?

Answer 33

using a tool to make concrete surface smooth

Question 34

How often and how deep is a control joint?

Answer 34

1/4th the depth of slab. every 15'

Question 35

What are isolation joints for?

Answer 35

fully separating two concretes for expansion and contraction.

Question 36

Do thinner or thicker slabs require closer spacing of control joints?

Answer 36

thinner

Question 37

How do you have less control joints?

Answer 37

make concrete stronger via dryer mix, fly ash, post tensioning, admixtures or microfibers

Question 38

When do you need masonry expansion joints?

Answer 38

change in height, openings, wall thickness transitions, change directions, columns or pilasters

Question 39

How do you make non slip finish on concrete?

Answer 39

stiff bristle broom perpendicular to path of travel, drag burlap, sprinkle powder, or abrasive strips

Question 40

What are whalers?

Answer 40

formwork that holds the ties of the formwork. Horizontal members

Question 41

What is the formwork for a column called?

Answer 41

a pile cap

Question 42

What is a chamfer strip?

Answer 42

cast at 45 degrees for beveling corners

Question 43

What are shores?

Answer 43

adjustable height columns used to support the beams of a slab that is not being poured on grade

Question 44

What is the depth of a concrete beam?

Answer 44

Width x 3 = depth

Question 45

What type of concrete slab system is best for rectangles? for squares?

Answer 45

one way for rectangle, two way for squares

Question 46

What do drop panels do?

Answer 46

They help resist shear forces near the columns

Question 47

What type of concrete slab system is best for less than 25' spans?

Answer 47

two way flat plate or one way flat slab

Question 48

What type of concrete slab is best used for greater than 30' spans?

Answer 48

one way joist systems

Question 49

What are lifting rings?

Answer 49

rings cast into concrete for tilt up construction that connects to a rope crane

Question 50

How do you increase span?

Answer 50

pretensioning, taper, vault, arches, folded plates

Question 51

What is board formed concrete?

Answer 51

a type of architectural concrete where aggregate is exposed.

Question 52

What type of cement is used in precast concrete?

Answer 52

type 3

Question 53

How do you connect things to concrete?

Answer 53

precast bolts, drill expansion anchors, glue steel plates, oversize a hole and put grout, concrete/masonry nails, steel tendons.

Question 54

What do superplasticizers do?

Answer 54

they are water reducing admixtures, organic. they increase work ability so it is easier to flow into convoluted forms. it allows reduced water but maintains workable.

Question 55

What is grade 75 steel used for?

Answer 55

making columns thinner

Question 56

What are bolsters?

Answer 56

longer chairs to hold the rebar, often if slab on grade it is made of plastic