Quiz 2

Question 1

Properties of the hardened concrete
important to the materials engineer are:

Answer 1

• Strength
• Modulus of Elasticity
• Durability
• Porosity

Question 2

is generally the controlling design
factor. Unless otherwise specified, concrete
strength f′c refers to the average
compressive strength of three tests.

Answer 2

Strength

Question 3

is
desired for mixes with low cement content to
promote workability.

Answer 3

Low Fineness Modulus

Question 4

is defined as the ease of
placing, consolidating, and finishing freshly
mixed concrete.

Answer 4

Workability

Question 5

is an indicator of
workability when evaluating similar
mixtures. This test consists of filling a
truncated cone with concrete, removing
the cone, then measuring the distance
the concrete slumps (ASTM C143).

Answer 5

Slump Test

Question 6

is measuring and introducing the concrete
ingredients into the mixer.

Answer 6

Batching

Question 7

is
mixed in a central plant
and delivered to the job
site in mixing trucks
ready for placing.

Answer 7

Ready-mixed Concrete

Question 8

3 mixing methods can be used for
ready-mixed concrete:

Answer 8

1. Central-mixed concrete
2. Shrink-mixed concrete
3. Truck-mixed concrete

Question 9

is mixed
completely in a stationary mixer and
delivered in an agitator truck (2 rpm to 6
rpm).

Answer 9

Central-mixed concrete

Question 10

is partially mixed
in a stationary mixer and completed in a
mixer truck (4 to 16 rpm).

Answer 10

Shrink-mixed Concrete

Question 11

is mixed
completely in a mixer truck (4 to 16 rpm)

Answer 11

Truck-mixed Concrete

Question 12

It can be mixed in a mobile
batcher mixer at the job site.

Answer 12

Mobile Batcher Mixed Concrete

Question 13

should be
deposited continuously as close as possible
to its final position.

Answer 13

Depositing Concrete

Question 14

is frequently used for large
construction projects. Special pumps deliver the concrete directly into the forms.

Answer 14

Pump Concrete

Question 15

Quality concrete requires thorough
consolidation to reduce the entrapped air
in the mix

Answer 15

Vibration of Concrete

Question 16

The pressure
method is based on _______, which
relates pressure to volume.

Answer 16

Boyle’s Law

Question 17

compares the unit weight of freshly mixed
concrete with the theoretical maximum
unit weight of the mix.

Answer 17

Gravimetric Method

Question 18

can be used
for concrete made with any type of
aggregate. The basic process involves
placing concrete in a fixed volume
cylinder

Answer 18

Volumetric Method

Question 19

is a
quick method used to determine the air
content of freshly mixed concrete

Answer 19

Chace Air Indicator Test

Question 20

is the process of maintaining
satisfactory moisture content and
temperature in the concrete for a definite
period of time.

Answer 20

Curing

Question 21

is a
long-term process and requires water and
proper temperature.

Answer 21

Hydration of Cement

Question 22

involves covering the exposed
surface of the concrete structure with
water.

Answer 22

Ponding

Question 23

A system of nozzles or sprayers can provide
continuous spraying or fogging This
method requires a large amount of water
and could be expensive. It is most suitable
in high-temperature and low humidity envi
ronments.

Answer 23

SPRAYING / FOGGING

Question 24

Moisture-retaining fabric coverings saturated
with water, such as burlap, cotton mats, and
rugs, are used in many applications

Answer 24

Wet Coverings

Question 25

which is the most common technique for evaluating workability acrossthe world.

Answer 25

Slump Test

Question 26

is better suited for adequately measure the workability of stiff and dry mixes.

Answer 26

Vee Bee Test

Question 27

a given volume of concrete undergoes free fall from one hopper to the second, and then into a cylindrical container.

Answer 27

Compaction Factor Test

Question 28

involves the spread of a truncated cone of concrete on a table that is dropped a number of times.

Answer 28

Flow Table Test

Question 29

is a quality index, because its correlates with other characteristics as: compaction, mechanical strength, permeability, freeze – thaw resistance and etc.

Answer 29

Specific Weight

Question 30

It is considered only when it is required as a necessity in the design project that establishes the maximum and minimum valuesfor concrete temperature.

Answer 30

Temperature

Question 31

defined as the largest stress that does not cause a measurable permanent strain.

Answer 31

Elastic Limit

Question 32

is commonly used in designing concrete structures. Since the stress-strain relationship is not exactly linear, the classic definition of the modulus of elasticity (Young’s modulus) is not applicable.

Answer 32

Modulus of Elasticity

Question 33

s used in advanced structural analysis of shell roofs, flat-plate roofs, and mat foundations. Poisson’s ratio of concrete varies between 0.11 and 0.21,

Answer 33

POISSON’S RATIO

Question 34

is an important property of concrete because concrete structures are highly vulnerable to tensile cracking due to various kinds of effects and applied loading itself.

Answer 34

Tensile Strength

Question 35

is used to evaluate the shear resistance provided by concrete in reinforced lightweight aggregate concrete members.

Answer 35

Split Tensile Strength

Question 36

measures the tensile strength of concrete. In this test, a 0.15-m by 0.30-m (6-in. by 12-in.) concrete cylinder is subjected to a compressive load at a constant rate along the vertical diameter until failure.

Answer 36

SPLIT TENSION TEST

Question 37

The specimen is prepared either in the lab or in the field in accordance with ASTM C192 or C31, respectively.

Answer 37

FLEXURE STRENGTH TEST

Question 38

It is a measure of an unreinforced concrete beam or slab to resist failure in bending.

Answer 38

Flexture Strength

Question 39

also known as the Schmidt hammer test, is a nondestruc tive test performed on hardened concrete to determine the hardness of the surface

Answer 39

Rebound Hammer Test

Question 40

also known as the Windsor Probe test, is standardized by ASTM C803.

Answer 40

PENETRATION RESISTANCE TEST

Question 41

measures the velocity of an ultra sonic wave passing through the concrete. This test is used to detect cracks, discontinuities, or internal deterioration in the structure of concrete.

Answer 41

ULTRASONIC PULSE VELOCITY TEST

Question 42

is defined as the degree of cement hydration, which varies as a function of both time and temperature.

Answer 42

Maturity

Question 43

an ultimate strength pertaining to the failure of beams by flexure equal to the bending moment at rupture divided by the section modulus of the beam

Answer 43

Modulus of Rupture