Concrete

Question 1

Mixture of fine and coarse aggregates with cement and water

Answer 1

Concrete

Question 2

Combination of water and cement

Answer 2

Paste

Question 3

Combination of paste & fine aggregates

Answer 3

Mortar

Question 4

Concrete used for superstructures and heavily reinforced substructures

Answer 4

Class A concrete

Question 5

Concrete used for unreinforced or with small reinforcement footings, pedestals, massive pier shafts

Answer 5

Class B concrete

Question 6

Thin reinforced sections

Answer 6

Class C concrete

Question 7

Prestressed concrete structures

Answer 7

Class P concrete

Question 8

Concrete deposited in water

Answer 8

Seal

Question 9

Stages of Concrete formation

Answer 9

Mixing
Dormancy
Hardening
Cooling
Densification

Question 10

The reaction between C3A and CAH (tricalcium aluminate & aluminate hydrate)

Answer 10

Mixing

Question 11

The mixture remains plastic with no heat generation.

Answer 11

Dormancy

Question 12

The mix starts to stiffen, stage dominated by silicate reactions

Answer 12

Hardening

Question 13

Concrete shrinks: Shrinkage is restrained by friction from underlying layers

Answer 13

Cooling

Question 14

Hydration continues if cement and water are still present in the mixture

Answer 14

Densification

Question 15

Materials added to concrete mixtures to modify their properties

Answer 15

Admixtures

Question 16

Concrete properties commonly modified by admixtures

Answer 16

Rate of Hydration
Workability
Dispersion
Air-entrainment

Question 17

Used to speed up the initial set of concrete by increasing the rate of hydration to shorten the setting time

Answer 17

Accelerators

Question 18

Used to slow down the setting of concrete and delay initial setting time up to 4 hours

Answer 18

Retarders

Question 19

Obtain higher strength by decreasing the water-cement ratio at the same workability as an ordinary mix

Answer 19

Water reducer or plasticizer

Question 20

For normal workability but with extremely high strength due to a very low water-cement ratio

Answer 20

Superplasticizer

Question 21

Admixtures help incorporate a controlled amount of air in form of minute bubbles (0.01-0.25 mm dia.)

Answer 21

Air-entraining admixtures

Question 22

Materials used for preventing or delaying drying up of intrinsic moisture inside the capillaries of the concrete

Answer 22

Curing materials

Question 23

Physical properties of concrete

Answer 23

Workability
Durability
Strength
Impermeability

Question 24

Empirical test that measures the workability of fresh concrete

Answer 24

Slump test

Question 25

A curing method is where concrete is continuously wet by the application of water for a minimum period of 7 days after the concrete has been placed.

Answer 25

Water method

Question 26

Curing method where the application of an impervious membrane and shall be practically colorless liquid

Answer 26

Curing compound

Question 27

A Curing method is where water is sprayed using a nozzle that atomizes the flow into a mist.

Answer 27

Waterproof membrane method

Question 28

Pre-cast concrete members are steamed for a minimum of 4 hours

Answer 28

Steaming curing method