Lesson 5 Flashcards

(95 cards)

1
Q

is a building material which solidifies and hardens after mixing with water and placement due to chemical process known as hydration.

A

Concrete

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

The water reacts with cement, which bonds the other components fine aggregates (sand) and coarse aggregates (gravel) together; and eventually produces a hard stone-like material.

A

Concrete

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

is used to make pavements, pipe, engineering structures, foundations, roads, bridges, walls, footings, etc.

A

Concrete

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

Classifications of Concrete

A
  • general classification
  • classification according to portion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

2 General Classification of Concrete

A
  • plain concrete
  • Reinforced Concrete
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

A structural concrete with no reinforcement or with less reinforcement than the minimum amount specified for reinforced concrete.

A

Plain Concrete

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

A structural concrete reinforced with no less than the minimum amounts of reinforcing bars, pre-stressing tendons or non-pre-stressed reinforcement.

A

Reinforced Concrete

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

4 Classifications of Concrete According to Proportions

A
  • Class AA
  • Class A
  • Class B
  • Class C
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A rich concrete mixture that can be used for columns of reinforced concrete building and for construction where a very strong and dense concrete is required.

A

Class AA

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

A good concrete mixture that can be used for reinforced concrete works of all kinds and best suited for general concrete works.

A

Class A

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

A medium concrete mixture that can be used for plain concrete foundations, walls, floors, etc. and for not much strength of impermeability is required

A

Class B

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

A lean concrete mixture that can be used for heavy masses.

A

Class C

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

Classification of cement with 1:1.5:3 ratio.

A

Class AA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Classification of cement with Concrete works for docks, water structure, reservoir in nature of work.

A

Class AA

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

Classification of cement with 1:2:4
ratio

A

Class A

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

Classification of cement with Reinforced concrete works buildings, bridges and tunnels in nature of work.

A

Class A

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

Classification of cement with 1:2.5:5 ratio

A

Class B

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

Classification of cement with Heavy walls, retaining walls, piers, abutments, floor and arches in nature of work

A

Class B

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

Classification of cement with 1:3:6 ratio

A

Class C

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

Classification of cement with Mass concrete, backing for stone masonry, concrete blocks in nature of work

A

Class C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The main ingredient is slaked lime and used as a binding material

A

Lime Concrete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

6 Types of Cement Concrete (PSHARP)

A
  • Pre-packed Concrete
  • Special Cerment Concrete
  • Heavy Weight Concrete
  • Aerated Concrete
  • Reinforced Cement Concrete
  • Pre-Stressed Cement Concrete
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Produced to suit a variety of special requirements of environmental condition.

A

Special Cerment Concrete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

This is obtained by embedding steel bars in tension zones of the structural member to offset tension weakness of plain cement concrete.

A

Reinforced Cement Concrete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
This is obtained with high graded steel wires or tendon wires.
Pre-Stressed Cement Concrete
26
Manufactured from calcareous and siliceous materials.
Aerated Concrete.
27
Produced by using special heavy-weight aggregates and compacting well by mechanical means
Heavy Weight Concrete
28
Obtained by packed and injecting cement sand mortar under pressure to fill voids already fully compact coarse aggregates.
Pre-packed Concrete
29
3 Special Types of Concrete (HAL)
- High-Early Strength Concrete - Air Entrained Concrete - Light weight Concrete
30
Contains billions of microscopic cells per ft^3 and is produced by the use of air entraining Portland cement.
Air Entrained Concrete
31
Produced by using high-early strength cement.
High-Early Strength Concrete.
32
Made from light weight aggregates
Light weight Concrete
33
7 Mix Proportioning Method for Concrete WM WAFAM
- Weight Method - Maximum density Method - Water Cement Ratio - Absolute-Volume Method - Fineness Modulus Method - Arbitrary Standard Method - Minimum Voids Method
34
Fairly simple and quick for estimating mix proportion using an assumed or known weight of concrete per unit volume
Weight Method
35
More accurate method involves used of specific gravity values for all ingredients to calculate the it and each will occupy in a unit volumes of concrete.
Absolute-Volume Method
36
It is used to indicate an index number which is roughly proportional to the average size of the particle in the entire quantity of aggregates
Fineness Modulus
37
Ratio of fine agregates and coarse aggregates to develop a dense mix that lies between 1:1/2 and 1:2/1/2.
Arbitrary Standard Method
38
The quantity of fine aggregate used in the mixed is about 10% more than the voids in the coarse aggregates and the quantity of cement is kept about 15% more than the voids in the fine aggregates
Minimum Voids Method
39
In this method a box of fixed volume is filled with varying proportion of fine and coarse aggregates.
Maximum density Method
40
The amount of water in mixing concrete is the most important factor affecting the strength of a given proportion
Water Cement Ratio
41
Properties of concrete are divided into two parts:
- Properties of Fresh Concrete or Plastic Stage - Properties of Hardened Concrete
42
is a measure of the stiffness or sloppiness or fluidity of the mix.
Consistency of a concrete mix or Consistency
43
It is therefore necessary to measure the consistency of concrete at _______________.
regular intervals
44
It is therefore necessary to measure this at regular intervals.
consistency of concrete
45
Commonly used to measure consistency of concrete
Slump Test
46
From the time of mixing, fresh concrete gradually loses ___________.
consistency
47
It is caused due to the following reasons: hydration of cement (generating more heat), loss of water by evaporation, absorption of water by dry aggregates and absorption of water by surfaces in contact with the concrete
slump loss in concrete/slump loss
48
The ease which concrete can be compacted fully without segregation and bleeding.
Workability
49
It is the relative ease with which concrete can be placed, compacted and finished without separation or segregation of the individual materials
workability of a concrete mix
50
True or False Workability is the SAME thing as consistency.
false ; NOT THE SAME
51
This is not the same thing as consistency
workability
52
True or False Mixes with the same consistency can have different workability's, if they are made with different sizes of stone; the smaller the stone the more workable the concrete
True
53
True or False It is POSSIBLE to measure workability but the slump test, together with an assessment of properties like stone content, cohesiveness and plasticity; it gives a useful indication.
false ; NOT POSSIBLE
54
Implies the separation of the coarser particles from the mix which results in non homogeneity of the concrete mix
Segregation
55
The appearance of water along the cement particles on surface of freshly laid concrete on compaction and finishing
Bleeding
56
Cement and aggregate particles have densities about three times that of water. In fresh concrete they consequently tend to settle and displace mixing water which migrates upward and may collect on the top
Settlement and Bleeding
57
The hardening of concrete before its hydration is known as ______________.
Setting
58
It derives its strength by the hydration of cement particles.
Concrete
59
The _____________ of cement is not a momentary action but a process continuing for a long time.
hydration
60
it reduces the density of concrete and consequently reduces the strength.
Air entrainment.
61
8 Factors under the Plastic Stage CHS SWABS
- Consistency - Hydration - Segregation - Setting - Workability - Air entrainment - Bleeding - Settlement and Bleeding
62
The characteristics ___________ of concrete is defined as the compressive strength of 150 mm size cubes after 28 days of curing below which not more than 5 % of the test results are expected to fail.
strength
63
When we refer to concrete strength, we generally talk about ______________ of concrete.
compressive strength
64
When we refer to ___________________, we generally talk about compresive strength of concrete.
concrete strength
65
It is strong in compression but relatively weak in tension and bending.
concrete
66
it is measure in pounds per square inch (psi) or newton per square millimeter (MPa)
concrete compressive strength
67
It mostly depends upon the amount and type of cement used in concrete mix.
Compressive strength
68
It is also affected by the water-cement of ratio, mixing method, placing and curing.
Compressive strength
69
It ranges from 7% to 12% compressive strength.
Concrete tensile strength
70
Both ______________ and ______________ can be increased by adding reinforcement.
tensile strength and bending strength
71
The period existence of concrete without getting adversely affected by these forces is known as ____________.
durability
72
might be defined as the ability to maintain satisfactory performance over and extended service life
durability
73
True or False The design service life of most buildings is often 30 years, although buildings often last 50 to 100 years.
true
74
True or False Most concrete buildings are demolished due to DETERIORATION rather than OBSOLESCENCE
false ; due to OBSOLESCENCE rather than DETERIORATION
75
it requiresc different degrees of durability depending on the exposure environment and properties desired
concrete
76
The resistance of concrete to the flow of water through its pores.
Impermeability
77
Excess water during concreting leaves a large number of continuous pores leading to ______________.
permeability
78
Concrete shrinks with age and the total shrinkage depends upon the constituents of concrete, size of the member and the environmental conditions
Dimensional changes
79
It is approximately 0.0003 of original dimension.
Total shrinkage
80
The volume decrease of concrete caused by drying and chemical changes.
Shrinkage
81
In another word, the reduction of volume for the setting and hardening of concrete is defined as ______________.
shrinkage
82
Deformation of concrete structure under sustained load is defined as _______________.
concrete creep
83
This deformation usually occurs in the direction the force is applied
creep
84
The permanent dimension change due to loading over a long period is termed as _________.
creep
85
this depends on the Modulus of Elasticity of the concrete ingredients and their mix proportions.
modulus of Elasticity
86
Sometimes it is called the impermeability of concrete
Water Tightness.
87
Water Tightness is sometimes called _____________.
impermeability of concrete
88
_________ of concrete is directly related to the durability of concrete
Water tightness
89
True or False The MORE the permeability; the the more the durability of concrete.
false ; The LESSER the permeability; the more the durability of concrete
90
this has moderate thermal conductivity, much lower than metals, but significantly higher than other building materials such as wood, and it is a poor insulator.
concrete
91
is frequently used for 'fireproofing' of steel structures.
layer of concrete
92
Concrete has moderate _______________, much lower than metals, but significantly higher than other building materials such as wood, and it is a poor insulator.
thermal conductivity
93
However, the term ____________ is inappropriate, for high temperature fires can be hot enough to induce chemical changes in concrete: which in the extreme can cause considerable structural damage to the concrete.
fireproof
94
The _________ of concrete depends on percentage of reinforcement, type of aggregate and amount of voids.
unit weight
95
is a method used to maintain a satisfactory moisture content and temperature in a concrete for a period of time immediately after placing and finishing to develop the desired properties for its intended used.
Curing of Concrete