Lesson 6

Question 1

It is a binder, a substance that sets and hardens as it dries and also reacts with carbon dioxide in the air dependently, and can bind other materials together.

Answer 1

Cement

Question 2

It traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed rock with burnt lime as binder.

Answer 2

cement

Question 3

It is to describe masonry resembling modern concrete that was made from crushed rock with burnt lime as binder.

Answer 3

opus caementicium

Question 4

The word “cement” traces to the Romans, who used the term _____________________ to describe masonry resembling modern concrete that was made from crushed rock with burnt lime as binder.

Answer 4

opus caementicium

Question 5

The volcanic ash and pulverized brick additives that were added to the burnt lime to obtain a hydraulic binder were later referred to as ____________, _______________, ___________, and ______________.

Answer 5

cementum, cimentum, cäment, and cement.

Question 6

Cements used in construction can be characterized as being either ______________ and _______________, depending upon the ability of the cement to be used in the presence of water.

Answer 6

hydraulic or non-hydraulic

Question 7

is made by replacing some of the cement in a concrete mix with activated aluminum silicates, pozzolanas, such as fly ash, to activate cement setting in wet conditions or underwater and further protect hardened concrete from chemical attack. (e.g., Portland cement) hardening because of hydration.

Answer 7

Hydraulic cement

Question 8

This will not set in wet conditions or underwater, and is attacked by some aggressive chemicals after setting.

Answer 8

Non-hydraulic cement

Question 9

a combination of cement and an aggregate to form a strong building material.

Answer 9

concrete

Question 10

One of the most important uses of cement is being an ingredient in the production of _________ in masonry.

Answer 10

mortar

Question 11

One of the most important uses of cement is being an ingredient of __________, a combination of cement and an aggregate to form a strong building material.

Answer 11

Concrete

Question 12

are important to civil engineers, because it is by these properties that the engineer judges the suitability of cements

Answer 12

main properties of hydraulic cement

Question 13

___________________ of concrete is the result of the reaction of water with cement particles.

Answer 13

Strength development

Question 14

True or False

The reaction always starts between water and cement particle at its surface. Thus, the SMALLER the surface
area available for reaction, greater is the rate of hydration.

Answer 14

false ; LARGER

Question 15

It is a very important property.

Answer 15

Fineness of cement

Question 16

True or False

The FINER the cement, the quícker it sets.

Answer 16

true

Question 17

The active element in the cement

Answer 17

Impalpable powder

Question 18

True or False

About 40%-50% of standard Portland cement is INACTIVE and the rest is to some extent inert.

Answer 18

false ; ACTIVE

Question 19

_______________ of Cement is measured either in terms of: percentage of weight retained after sieving cement through 90 micron sieve and surface area of cement in cm² per gram.

Answer 19

Fineness

Question 20

is the action of changing from a fluid state to a solid state; and should not be confused with ‘hardening’.

Answer 20

Setting

Question 21

is a process by which a material acquires greater hardness, such as cold forming or heat treatment.

Answer 21

Hardening

Question 22

During the next stage of hydration, _____________ starts hardening owing to the reaction of C3S and C2S with water and the paste gains strength

Answer 22

cement paste

Question 23

During the next stage of _________, cement paste starts hardening owing to the reaction of C3S and C2S with water and the paste gains strength

Answer 23

hydration

Question 24

True or False

In the first few minutes, the setting action is more predominant and later on the hardening action becomes dominant.

Answer 24

true

Question 25

It is not much value for the determination of degree of calcination

Answer 25

Specific Gravity Test

Question 26

this test is valuable for detecting adulteration

Answer 26

Specific Gravity Test

Question 27

This test is also of some value in determining the solidity of mortar and concrete.

Answer 27

Specific Gravity Test

Question 28

The specific gravity of good Portland cement should be between ________ and _________.

Answer 28

3.15 and 3.20.

Question 29

The ______________ of good Portland cement should be between 3.15 and 3.20.

Answer 29

specific gravity

Question 30

True or False

It is important that the cement, after setting, shall not undergo any appreciable amount of volume

Answer 30

True

Question 31

This test is to determine that the cement does not show any appreciable subsequent expansion, is of prime importance.

Answer 31

testing of soundness of cement

Question 32

Certain ____________ have been found to undergo a large expansion after setting, causing disruption of the set and hardened mass.

Answer 32

cements

Question 33

The ______________________________ is the most important for structural design

Answer 33

mechanical strength of hardened cement

Question 34

it is also important to note the difference between ___________ and _____________ time of cement.

Answer 34

setting and hardening

Question 35

Two functions of compressive strength test.

Answer 35

1. to final check on the quality of cement
2. classify cement according to the strength it gives after 3 days and 7 days of curing

Question 36

It is the most important property of hardened cement.

Answer 36

Compressive Strength

Question 37

True or False. Therefore, it is not surprising that the cement is always tested for its elasticity at the used in laboratory before the cement is important works.

Answer 37

False (elasticity - strength)

Question 38

Why are strength test not made on neat cement paste?

Answer 38

because of difficulties of excessive shrinkage and subsequent cracking

Question 39

It is the mixture indirectly found on specific proportions.

Answer 39

Strength of cement

Question 40

It is used for finding the strength of cement.

Answer 40

Standard sand

Question 41

It is the chemical reaction between cement and water.

Answer 41

Heat and Hydration

Question 42

True or False. Heat and Hydration is the chemical reaction between cement and sand.

Answer 42

False (sand - water)

Question 43

It is the process of changing mixed cement with water into a liquid state, to a solid state.

Answer 43

Setting Time of Cement

Question 44

The time cement harden sufficiently and the hydration of cement with water is almost completed.

Answer 44

Setting time of cement

Question 45

It is define as the period of elapsing between the needle of 1 mm square section fails to pierce the test block to a depth of about 5 mm from the bottom of the mold.

Answer 45

Initial Setting Time

Question 46

Initial setting time is define as the period of elapsing between the needle of __ mm square section fails to pierce the test block to a depth of about __ mm from the bottom of the mold.

Answer 46

1;5

Question 47

Wnat is the minimum initial setting time for ordinary and rapid hardening Portland cement?

Answer 47

30 minutes

Question 48

Wnat is the minimum initial setting time for low heat cement?

Answer 48

60 minutes

Question 49

It is define as the period elapsing between the time when water is added to cement and the time

Answer 49

Final setting time

Question 50

What is the maximum time specified for the final set for all the above mentioned Portland Cement?

Answer 50

600 minutes

Question 51

It is used to test the setting power of cement.

Answer 51

Vicat Needle Apparatus

Question 52

It is a method that determines the time of setting of hydraulic cement by means of Vicat Needle Apparatus

Answer 52

Test for setting of hydraulic cement

Question 53

Why do we need gloves, protective clothing and eye protection in testing for setting of hydraulic cement?

Answer 53

fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.