Concrete

Question 1

A hard compact building material formed when a mixture of cement, sand, gravel, and water undergoes hydration.

Answer 1

Concrete

Question 2

4 parts calcined limestones plus 1 part clay which are mixed, burned, and pulverized, sold in 40 kilos per bag.

Answer 2

Cement

Question 3

Fine aggregates, natural sand kr crushed stone well graded.

Answer 3

Sand

Question 4

Course aggregates, crushed stone or blast furnace slags.

Answer 4

Gravel

Question 5

Clean, potable and free from harmful substances.

Answer 5

Water

Question 6

Additive as required by situations, ingredients added to concrete or mortar modify its properties immediately before or after mixing.

Answer 6

Admixture

Question 7

Strength of Class AAA concrete

Answer 7

4500 psi

Question 8

Strength of Class AA concrete

Answer 8

4000 psi

Question 9

Strength of Class A concrete

Answer 9

3500 psi

Question 10

Strength of Class B concrete

Answer 10

3000 psi

Question 11

Strength of Class C concrete

Answer 11

2500 psi

Question 12

Strength of Class D concrete

Answer 12

2000 psi

Question 13

Used in pre stresses and post tensioned

Answer 13

Class AAA

Question 14

Used in underwater retaining wall, shear wall and core elevator core walls

Answer 14

Class AA

Question 15

Used in footings, pier, column, girders, beams, joists and slabs

Answer 15

Class A

Question 16

Used in slabs on fill and non-load bearing wall or 4” CHB

Answer 16

Class B

Question 17

Used in concrete plant boxes and parapet walls

Answer 17

Class C

Question 18

Used in plant boxes, footpaths, walkway and lean concrete

Answer 18

Class D

Question 19

Low strength concret

Answer 19

<20 MPa (<3000 psi)

Question 20

Moderate strength concrete

Answer 20

20-40 MPa (3000-6000 psi)

Question 21

High strength concrete

Answer 21

> 40 MPa (>6000 psi)

Question 22

Controls the strength, durability, and water tightness of hardened concrete.

Answer 22

Water-Cement Ratio

Question 23

The compressive stress of concrete is _____ proportional to the ratio of water ti cement.

Answer 23

Inversely

Question 24

Average water-cement ratio

Answer 24

6 gals per 40 kg

Question 25

Emergence of excess mixing water of the surface of newly placed concrete cause of settlement of solids within the mass.

Answer 25

Bleeding

Question 26

Milky deposit containing cement and fine aggregates on the surface of new concrete combined with bleeding.

Answer 26

Laitance

Question 27

Long duration stress produces stress over time and consequently causes PEERMANENT DEFORMATION.

Answer 27

Creep

Question 28

Concrete is incombustible and somewhat insulative

Answer 28

Fire Resistance

Question 29

Can be controlled by providing expansion joints and steel reinforcements.

Answer 29

Shrinkage

Question 30

Relative to durability and appearance

Answer 30

Hardness

Question 31

Sizes of pores left during hydration process or created by excessive evaporation and shrinkage cracks affecting the water-tightness of concrete.

Answer 31

Porosity

Question 32

The requirements are based on “Rapid Chloride Permeability Test”.

Answer 32

Durability

Question 33

Depends on its rheological properties defined by yield stress and plastic viscosity.

Answer 33

Workability

Question 34

The effort needed to initiate movement of the fresh concrete and correlates with slump.

Answer 34

Yield stress

Question 35

The flow characteristics of the concrete while moving.

Answer 35

Plastic Viscosity

Question 36

Useful in confined zones where vibrating compaction is difficult.

Answer 36

Self compacting concrete

Question 37

Required to absorb the concrete’s weakness in tensile and shear stress.

Answer 37

Steel reinforcement