Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Concrete > Concrete > Flashcards

Concrete Flashcards

1
Q

what are some of the raw materials in Portland Cement

A
  • limestone
  • cement rock
  • oyster shells
  • marl (lime rich mud-lake sediment)
  • clay
  • silica sand
  • iron ore
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Raw materials are ground down and heated to temperatures between ______ and ______ degrees (F) to form hard pellets called “_____”

A

2,000 and 3,000

Clinkers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is air entrainment

A

the intentional creation of tiny air bubbles in concrete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the composition of concrete

A

mix of aggregates and entrained air held together by hardened paste made of cement and water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the most commonly used cement by the military

A

portland cement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the chemical reaction when portland cement is mixed with water

A

hydration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what causes concrete to harden and what is the desired temp.

A

hydration and 73 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the three major components of concrete

A
  • water
  • aggregates
  • portland cement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are two types of aggregate

A

coarse (rock) and fine (sand)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the primary purpose of aggregates in concrete

A

to gain economy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the total percent of volume in concrete

A

60 to 80 percent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the most common contaminating materials of aggregate

A

dirt, clay and salt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the five types of portland cement

A
  • type 1: normal portland
  • type 2: modified
  • type 3: high early
  • type 4: low heat
  • type 5: sulfate resistant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the normal cure time and some uses of type 1 portland cement

A

28 days

pavement, sidewalks, bridges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the normal cure time and uses of type 2 portland cement

A

45 days

large super structures, large piers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the normal cure time and uses of type 3 portland cement

A

7 days

used in cold weather and high heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the normal cure time and uses of type 4 portland cement

A

90 days

large massive structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the normal cure time and uses of type 5 portland cement

A

60 days

used where the soil, or water, in contact with the concrete has a high sulfate content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what types of portland cement are air entrained

A

types 1, 2 and 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what does calcium chloride do to portland cement

A

accelerates both hardening and strength gain by 2 percent the weight of cement 2 hrs vs 6 hrs

21
Q

how does portland cement ship

A

bags- 94lbs, contain one cu ft of loose measurement

barrels- 376 lbs = four bags

rail cars

22
Q

what is “warehouse pack”

A

sacked cement in storage packed too tightly

23
Q

what are the types of concrete

A
  • reinforced
  • prestressed
  • precast
  • lightweight
24
Q

what is reinforced concrete

A

when steel rods are embedded in the concrete

25
Q

what is prestressed concrete

A

steel or welded wire mesh that is strecthed out with tension before the concrete is poured

26
Q

what is precast concrete

A

concrete cast into something other than its final position

27
Q

what does a good “plastic state” for concrete mean

A
  • readily moldable
  • changes shape slowly if forms are removed
  • uniform
28
Q

what are some advantages of concrete

A
  • high compressive strength
  • can be cast, molded or shaped
  • little maintenance
  • durable
29
Q

what are some disadvantages of concrete

A
  • low tensile strength
  • expands and contracts
  • shrinks when dry
  • heavy
30
Q

expansion joints should never be less than ____ in wide

A

1/4 inch

31
Q

what is the difference between construction joints and e​xpansion joints

A

construction joints do not allow for movement and expansion joints do

32
Q

if concrete must be placed underwater, what should the max velocity of the current be

A

ten ft per min

33
Q

when hand mixing cement, one man can mix approx. _______ cu yd per hour

A

one

34
Q

when hand mixing concrete the sand, gravel and cement should be dry mixed how many times before adding water

A

three times

35
Q

what is the formula for Project Volume (PV)

A

PV= Length x width x depth x # of structures, make sure to convert for inches

36
Q

what is the formula for Loss Factor (LF) for cu ft

A

LF= PV x LF (<5400 cu ft x 1.1 , >5400 cu ft x 1.05)

37
Q

what is the formula for Loose Volume (LV)

A

LV= LF amount x 1.5

38
Q

what rule do you use when calculating for materials when laying concrete

A

1-2-3 rule

1/6 cement

2/6 sand

3/6 gravel

39
Q

how do you convert cu ft to cu yrds

A

cu ft/27 = cu yards

40
Q

how do you convert cu yrds to cu ft

A

cu yards x 27 = cu ft

41
Q

when estimating for concrete work what is the rule called

A

the 3/2 rule

42
Q

what is the formula for Loss Factor (LF) for cu yards

A

LF= PV x LF(<200 cu yards x 1.1 or >200 cu yards x 1.05)

43
Q

forms can represent up to ___ of conrete scructure’s total cost

A

1/3

44
Q

forms are generally made of what four materials

A
  • wood
  • fiber
  • earth
  • metal
45
Q

what are the elements of wooden forms (concrete wall)

A
  • sheathing
  • studs
  • wales
  • strong backs
  • braces
  • shoe plates
  • spreaders
  • tie wires
46
Q

what are the elements of wooden forms (concrete column)

A
  • sheathing
  • batten
  • yokes
  • bracing
47
Q

the rate of filling should not exceed ____ ft per hour vertically, to avoid over-pressure on the forms

A

4 ft per hour

48
Q

what is screeding

A

the process of striking off the excess concrete in order to bring the surface to the right elevation

49
Q

what will produce a smoother finishing surface

floating or troweling

A

troweling will be smoother

Concrete (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions