CONCRETE

Question 1

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

Answer 1

CONCRETE

Question 2

The chemical process that occurs when water is added to cement.

Answer 2

HYDRATION

Question 3

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

Answer 3

CONCRETE

Question 4

General Classification of Concrete

Answer 4

PLAIN CONCRETE
REINFORCED CONCRETE

Question 5

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

Answer 5

PLAIN CONCRETE

Question 6

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

Answer 6

REINFORCED CONCRETE

Question 7

Classifications According to Proportion

Answer 7

CLASS AA
CLASS A
CLASS B
CLASS C

Question 8

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.

Answer 8

CLASS AA

Question 9

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

Answer 9

CLASS A

Question 10

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

Answer 10

CLASS B

Question 11

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

Answer 11

CLASS C

Question 12

1:1.5:3 , nature of work is concrete works for docks, water structure, and reservoir. , probable strength after 28 days is 3500 - 4000 psi

Answer 12

CLASS AA

Question 13

1:2:4 , nature of work is reinforced concrete works buildings, bridges and tunnels. . probable strength after 28 days is 2500 - 3000 psi

Answer 13

CLASS A

Question 14

1:2.5:5 , nature of work is heavy walls, retaining walls, piers, abutments, floor, and arches. , probable strength after 28 days is 1500 - 2000

Answer 14

CLASS B

Question 15

1:3:6 , nature of work is mass concrete, backing for stone masonry, concrete blocks. , probable strength after 28 days is 500 - 1000

Answer 15

CLASS C

Question 16

OTHER CLASSIFICATION OF CONCRETE

Answer 16

a. LIME CONCRETE
b. CEMCENT CONCRETE
c. SPECIAL TYPES OF CONCRETE

Question 17

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

Answer 17

LIME CONCRETE

Question 18

TYPES OF CEMENT CONCRETE

Answer 18

SPECIAL CEMENT CONCRETE
REINFORCED CEMENT CONCRETE
PRE-STRESSED CEMENT CONCRETE
AERATED CONCRETE
HEAVY WEIGHT CONCRETE
PRE-PACKED CONCRETE

Question 19

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

Answer 19

SPECIAL CEMENT CONCRETE

Question 20

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

Answer 20

REINFORCED CEMENT CONCRETE

Question 21

Obtained with high graded steel wires or
tendon wires.

Answer 21

PRE-STRESSED CEMENT CONCRETE

Question 22

Manufactured from calcareous and siliceous materials.

Answer 22

AERATED CONCRETE

Question 23

Produced by using special heavy weight aggregates
and compacting well by mechanical means.

Answer 23

HEAVY WEIGHT CONCRETE

Question 24

Obtained by injecting cement sand mortar under
pressure to fill voids already packed and fully compact coarse aggregates.

Answer 24

PRE-PACKED CONCRETE

Question 25

SPECIAL TYPES CONCRETE

Answer 25

AIR ENTRAINED CONCRETE HIGH-EARLY STRENGTH CONCRETE LIGHTWEIGHT CONCRETE

Question 26

Contains billions of microscopic cells per cubic ft and produced by the use of air entraining Portland cement.

Answer 26

AIR ENTRAINED CONCRETE

Question 27

. Produced by using high-early strength cement.

Answer 27

HIGH-EARLY STRENGTH CONCRETE

Question 28

Made from light weight aggregates.

Answer 28

LIGHTWEIGHT CONCRETE

Question 29

MIX PROPORTIONING METHOD

Answer 29

A. WEIGHT METHOD B. ABSOLUTE-VOLUME METHOD C. FINENESS MODULUS METHOD D. ARBITRARY STANDARD METHOD E. MINIMUM VOIDS METHOD F. MAXIMUM DENSITY METHOD G. WATER CEMENT RATIO

Question 30

Fairly simple and quick for estimating mix proportion using an assumed or known weight of concrete per unit volume.

Answer 30

WEIGHT METHOD

Question 31

More accurate method involves used of specific gravity values for all ingredients to calculate the absolute volume and each will occupy in a unit volume of concrete.

Answer 31

ABSOLUTE-VOLUME METHOD

Question 32

The term fineness modulus is used to indicate an index number which is roughly proportional to the average size of the particle in the entire quantity of aggregates.

Answer 32

FINENESS MODULUS METHOD

Question 33

Ratio of fine aggregates and coarse aggregates to develop a dense mix that lies between 1:1/2 and 1:2/1/2.

Answer 33

ARBITRARY STANDARD METHOD

Question 34

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.

Answer 34

MINIMUM VOIDS METHOD

Question 35

In this method a box of fixed volume is filled with varying proportion of fine and coarse aggregates.

Answer 35

MAXIMUM DENSITY METHOD

Question 36

The amount of water in mixing concrete is the most important factor affecting the strength of a given proportion.

Answer 36

WATER CEMENT RATIO

Question 37

PROPERTIES OF CONCRETE

Answer 37

A.PLASTIC STAGE CONSISTENCY. B. HARDENED STAGE

Question 38

PLASTIC STAGE CONSISTENCY.

Answer 38

SLUMP TEST SLUMP LOSS WORKABILITY SEGREGATION BLEEDING SETTLEMENT AND BLEEDING SETTING HYDRATION AIR ENTRAINMENT

Question 39

Commonly used to measure consistency of concrete.

Answer 39

SLUMP TEST

Question 40

From the time of mixing, fresh concrete gradually loses consistency. This gives rise to the problems only if the concrete becomes too stiff to handle, place and compact properly 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.

Answer 40

SLUMP LOSS

Question 41

The ease which concrete can be compacted fully without segregation and bleeding is the relative ease with which concrete can be placed, compacted and finished without separation or segregation of the individual materials. is not the Construction Materials and Testing - MGSD same thing as consistency. if they are made with different sizes of stone, the smaller the stone the more workable the concrete. It is not possible to measure this but the slump test, together with an assessment of properties like stone content, cohesiveness and plasticity; it gives a useful indication.

Answer 41

WORKABILITY

Question 42

. Implies the separation of the coarser particles from the mix which results in no homogeneity of the concrete mix.

Answer 42

SEGREGATION

Question 43

The appearance of water along the cement particles on surface of freshly laid concrete on compaction and finishing.

Answer 43

BLEEDING

Question 44

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

Answer 44

SETTLEMENT AND BLEEDING

Question 45

The hardening of concrete before its hydration is known as

Answer 45

SETTING

Question 46

Concrete derives its strength by the hydration of cement particles. The hydration of cement is not a momentary action but a process continuing for a long time.

Answer 46

HYDRATION

Question 47

reduces the density of concrete and consequently reduces the strength.

Answer 47

AIR ENTRAINMENT

Question 48

HARDENED STAGE

Answer 48

STRENGTH DURABILITY IMPERMEABILITY DIMENSIONAL CHANGES SHRINKAGE CREEP MODULUS OF ELASTICITY WATER TIGHTNESS THERMAL CONDUCTIVITY

Question 49

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.

Answer 49

STRENGTH

Question 50

Environmental forces such as weathering, chemical attack, heat, freezing, and thawing mat deteriorate concrete. The period existence of concrete without getting adversely affected by these forces is known as the ability to maintain satisfactory performance over and extended service life

Answer 50

DURABILITY

Question 51

The resistance of concrete to the flow of water through its pores. Excess water during concreting leaves a large number of continuous pores leading to the permeability.

Answer 51

IMPERMEABILITY

Question 52

Concrete shrinks with age and the total shrinkage depends upon the constituents of concrete, size of the member and the environmental conditions. Total shrinkage is approximately 0.0003 of original dimension.

Answer 52

DIMENSIONAL CHANGES

Question 53

The volume decreases of concrete caused by drying and chemical changes. In another word, the reduction of volume for the setting and hardening of concrete is defined as

Answer 53

SHRINKAGE

Question 54

Deformation of concrete structure under sustained load is defined as Long term pressure or stress on concrete can make changes in shape. This deformation usually occurs in the direction the force is applied. The permanent dimension changes due to loading over a long period is termed as

Answer 54

CREEP

Question 55

depends on the Modulus of Elasticity of the concrete ingredients and their mix proportions. As per ACI code, the modulus of Elasticity to be calculated using following equation: Ec= 33γc√fc′

Answer 55

MODULUS OF ELASTICITY

Question 56

Sometimes it is called impermeability of concrete. e is directly related to the durability of concrete. The lesser the permeability; the more the durability of concrete.

Answer 56

WATER TIGHTNESS

Question 57

Concrete has moderate thermal conductivity, much lower than metals, but significantly higher than other building materials such as wood, and it is a poor insulator. A layer of concrete is frequently used for 'fireproofing' of steel structures. However, the term fireproof 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.

Answer 57

THERMAL CONDUCTIVITY

Question 58

depends on percentage of reinforcement, type of aggregate and number of voids.

Answer 58

UNIT WEIGHT

Question 59

a method used to maintain a satisfactory moisture content and temperature in some concrete for a period of time immediately after placing and finishing to develop the desired properties for its intended used.

Answer 59

CURING OF CONCRETE