july november, 2015 · 2017-08-04 · modern construction materials (noc15-ce05) nptel online...

Modern Construction Materials (noc15-ce05)

NPTEL online course for 14 weeks July – November, 2015

Details of the questions set for the assignments

Week Week Details

Released on or

will be released

on

Released on

or will be

released on

Date of submission No. of

Questions

101/07/2015 -

07/07/201529-06-2015 02-07-2015 22-07-2015 5

208/07/2015 -

14/07/201505-07-2015 09/07/015 25-07-2015 8

315/07/2015 -

21/07/201513-07-2015 16-07-2015 25-07-2015 7

422/07/2015 -

28/07/201520-07-2015 22-07-2015 29-07-2015 5

529/07/2015 -

04/08/201527-07-2015 28-07-2015 05-08-2015 10

605/08/2015 -

11/08/201502-08-2015 05-08-2015 12-08-2015 12

712/08/2015 -

18/08/201510-08-2015 13-08-2015 20-08-2015 7

819/08/2015 -

25/08/201517-08-2015 20-08-2015 27-08-2015 15

926-08-2015 -

01/09/201524-08-2015 27-08-2015 03-09-2015 8

1002/09/2015 -

08/09/201531-08-2105 03-09-2015 10-09-2015 11

1109/09/2015 -

15/09/201507-09-2015 10-09-2015 17-09-2015 6

1216/09/2015 -

22/09/201514-09-2015 17-09-2015 24-09-2015 10

1323/09/2015 -

29/09/201521-09-2015 24-09-2015 01-10-2015 13

1430/09/2015 -

06/10/210528-09-2015 01-10-2015 08-10-2015 8

125

Metals-1, Metals-2 and Metals-3

Bituminous Materials-1, Bituminous Materilas-

2 and Concrete-1

Concrete-2, Concrete-3 and Concrete-4

Concrete-5, Glass and

Social perception of construction materials

Water Proofing Materials, Polymer Floor

Finishes and Anchors

Assignments

Chapter : MICRO STRUCTURE

Development of Microstructure-1

Chapter : MATERIAL BEHAVIOUR

Response to Stress-1, Response to Stress-2


Failure theories, Fracture Mechanics-1 and


Rheology and Thermal properties

Chapter : STRUCTURAL MATERIALS

Wood and wood products-1

Polymers

Fibre Reinforced Polymers-1 and

Lectures

Details

Chapter : BASICS

Prologue – Introduction to the course

Chapter : MICROSTRUCTURE

Atomic bonding-1, Atomic bonding-2 and

Chapter : MICROSTRUCTURE

Structure of solids-2, Structure of solids-3 and

ASSIGNMENT-1

1. Which of these material is more brittle that aluminium?

a) Structural steel

b) Timber

c) Titanium Alloys

2. Match the Following

1. Nanoscale A. Material is considered as homogenous

2. Meso scale B. Molecular structure and chemical composition.

3. Macro scale C. Material is composed of different, interacting phases

a) 1-C, 2-A, 3-B

b) 1-B, 2-C, 3-A

c) 1-A, 2-B, 3-C

d) 1-A, 2-C, 3-B

3. Consider a cantilever beam of dimensions b, d. The selection criteria for obtaining

required strength at minimum weight is determined by maximizing the term ‘X’. The

term ‘X’ is given by

a) E1/3

/ ρ

b) ρ/ σmax1/2

c) σmax1/2

/ ρ

d) ρ / E1/3

4. Assuming a normal or Gaussian distribution for the strength of tested samples, what

will be the approximate values of the risk factor k for failure rates of 10%?

1.4

5. Strength tests show that material A has a mean strength of 400 MPa with a

co‐efficient of variation of 12% whereas material B has the same strength with a

co‐efficient of variation of 23%. Material B is marginally cheaper than material A.

Which material would you choose?

A

ASSIGNMENT-2

1. Van de Waals bond can be easily broken by heat.

a) True

b) False

2. In the order of strength of the bonds which amongst the following is true

a) Ionic > Covalent > Hydrogen

b) Covalent > Ionic > Hydrogen

c) Hydrogen > Covalent > Ionic

3. The Condon Morse diagram given below represents which bond

a) Ionic bond

b) Metallic bond

c) Hydrogen bond

4. The boiling point of a material is proportional to the value of

a) Umin

b) R0

c) Ucryst

5. Strongly bonded solids have a higher thermal expansion

a) True

b) False

6. Match the following

1. Metallic Bond A. High thermal and electrical conductivity

2. Covalent Bond B. Non-directional

3. Ionic Bond C. 8-N Rule

a) 1-A, 2-B, 3-C

b) 1-B, 2-A, 3-C

c) 1-A, 2-C, 3-B

d) 1-B, 2-C, 3-A

7. Interlayer cations between the clay causes water adsorption and swelling in clay

a) True

b) False

8. Crystalline structures in which ions are bound directionally lead to random packed

structures

a) True

b) False

ASSIGNMENT-3

1. Which of the following properties are NOT associated with point defects?

a) Strengthening of alloys

b) Causes charge imbalance in clays

c) Increases the lattice binding energy

d) Strain increase in the crystal

2. Different orientation of crystals in a polycrystalline solid causes

a) Discontinuous crystal plane at the grain boundary

b) High energy at the grain boundary

c) Angles of misalignment at the interfacial zones.

d) Only 1 & 3

e) All 1, 2 & 3

3. Name the phenomenon depicted in the image

screw dislocation

4. Fill in the blank spaces: Point defects often occur in pairs. This is to avoid

____________ and also leads to minimisation of ________ within the crystal lattice.

Charge imbalance, strain

5. The image shown below is of ________ plane.

Twinning

6. Which of the following properties are attributed to metallic glasses? (More than one

option can be selected)

a) High resistance to cracking

b) Amorphous

c) Elastic

d) Low work to fracture ratio


1. Linear Polymers A. High strength polymers

2. Cross-Linked Polymers B. High degree of crystallinity

3. Network Polymers C. Covalent bonds between chains

D. Thermosets

a) 1-B; 2-C,D; 3-A

b) 1-B; 2-D; 3-A,C

c) 1-A; 2-C; 3-B,D

d) 1-C; 2-D; 3-A,B

ASSIGNMENT-4


1. Gibb’s phase rule at atmospheric pressure A. 1-2-1 Rule

2. Binary phase diagrams B. Eutectic

systems

3. Alloys with limited solubility C. f+p = n+1

4. Rule for finding the fraction of liquid and solid

compositions

D. Lever rule

a) 1-B; 2-C; 3-B; 4-D

b) 1-C; 2-A; 3-B; 4-D

c) 1-C; 2-D; 3-B; 4-A

d) 1-D; 2-C; 3-A; 4-B

2. The crystal growth resulting from crystallisation of melts occurs along preferential

directions like branches called as ___________ and their growth stops when

__________.

a) Branched structure, temperature falls

b) Dendritic structure, cooling rates are slow

c) Branched structure, nucleation is slow

d) Dendritic structure, dendrites meet

3. What is the liquid and solid compositions for the Cu-Ni alloy system shown in the

figure below at 40% Ni and 1300 degree Celsius?

a) 60% and 40%

b) 35% and 65%

c) 100% and 0%

d) 90% and 10%


1. Lotus leaves A. Lowers the zeta potential

2. Self-cleaning glass B. Super hydrophobicity

3. Super-plasticizers C. Increased wetting and

deflocculating

4. For complete wetting to

occur

D. Spreading force should be positive

a) 1-B; 2-C; 3-A; 4-D

b) 1-A; 2-C; 3-D; 4-B

c) 1-B; 2-C; 3-D; 4-A

d) 1-C; 2-B; 3-A; 4-D

5. The composition for the marked point "G" in the figure shown below is

a) 30% Al2O3 – 20% SiO2 – 50% CaO

b) 80% Al2O3 – 10% SiO2 – 10% CaO

c) 50% Al2O3 – 30% SiO2 – 20% CaO

d) 10% Al2O3 – 20% SiO2 – 70% CaO

ASSIGNMENT-5

1. Rubber has higher Young's modulus than Graphite

a) True

b) False

2. Brittle behaviour is when a material is able to support larger strains before failure

a) True

b) False

3. More the number of slip planes, easier the plastic deformation

a) True

b) False

4. Tensile strength decreases with the increase in temperature

a) True

b) False

5. Ductility increases with increase in strain hardening of the material

a) True

b) False

6. Surface cracks are more effective in causing cracks than internal cracks

a) True

b) False

7. Arrange the following in order of their mechanism w.r.t. primary creep deformation

a) BAC

b) ABC

c) CAB

d) BCA


1. Copper has this kind of structure A. Defects

2. Opposite of strain hardening B. FCC

3. Phenomenon leading to failure of metal in cold weather C. Annealing

4. Leads to difference in actual and theoretical value of

strength

D. Ductile to brittle

transition

a) 1-C; 2-B; 3-D; 4-A

b) 1-B; 2-C; 3-A; 4-D

c) 1-B; 2-C; 3-D; 4-A

d) 1-A; 2-C; 3-B; 4-D

9. Permanent deformation of material under load as a function of time is

a) Fracture

b) Annealing

c) Static fatigue

10. The pattern of S-N curve marked "A" in the following is for which material

a) Nylon 6

b) Polymethylmethacrylate

c) Aluminium alloy

ASSIGNMENT-6

1. Shear failure occurs ultimately under hydrostatic compression.

a) True

b) False

2. Failure theories are needed to represent material behaviour under uniaxial loading.

a) True

b) False

3. Concrete exhibits some non-linearity followed by post-peak drop in the stress level.

This phenomenon is called as ______

a) Stress relaxation

b) Strain hardening

c) Stress softening

d) Strain softening

4. The following idealised stress-strain curve represents which behaviour

a) Rigid –perfect plastic

b) Elastic-perfectly plastic

c) Elastic –linear strain hardening

d) Linear elastic

5. Match the following (If σ1 and σ3 are major and minor principal stresses, σ2 is

intermediate principal stress, Y is yield stress)

1. Octahedral shear stress theory i) (σ1-σ2)2 + ((σ2-σ3)

2 + (σ3-σ1)

2 = 2Y

2

2. Rankine theory ii) σ3-σ1 = ±Y

3. Tresca theory iii) σ1 = ±Y

a) 1-ii, 2-iii, 3-i

b) 1-i, 2-ii, 3-iii

c) 1-ii, 2-I, 3-iii

d) 1-i, 2-iii, 3-ii

6. Von-Mises theory predicts yielding better than Tresca theory because Tresca theory

ignores the effect of intermediate principal stresses.

a) True

b) False

7. Increase in all round confinement will lead to ductile failure.

a) True

b) False

8. According to Mohrs-columb theory more general failure envelope is ____

a) Straight line

b) Parabolic

9. Which of the following statements regarding Linear Elastic Fracture Mechanics

(LEFM) is wrong?

a) Fracture mechanics can be understood by either energy release (G) rate or stress

intensity factor (KI)

b) Stress concentration is inversely proportional to radius at crack tip

c) Stress intensity factor has the units MPa-m1/2

d) The relation between G and KI can be represented as G = KI/E2

(where KI is stress-intensity factor and G is energy release rate)

10. What is stress over the red marked region in the figure given below, if σ is the

applied tensile stress?

a) Lesser than σ

b) More than σ

c) Equal to σ

11. Match the following materials with their failure mechanisms

1. Glass i) crazing

2. Metals ii) brittle

3. Polymers iii) yielding

a) 1-ii, 2-I, 3-iii

b) 1-ii, 2-iii, 3-i

c) 1-ii, 2-iii, 3-iii


1. Crack blunting i) crazing

2. Non-linear fracture mechanics ii) rising resistance curve

3. Stress whitened region iii) ductile-tearing

4. Fibres iv) bridging

a) 1-ii, 2-iv, 3-i, 4-iii

b) 1-ii, 2-iii, 3-i, 4-iv

c) 1-ii, 2-iv, 3-i, 4-iii

d) 1-iii, 2-ii, 3-i, 4-iv

ASSIGNMENT-7

1. The components of the Kelvin model are ________ and ____________ elements.

Hookeian, Newtonian

2. What is the SI unit of viscosity?

Poise

3. Viscosity of gas increases with increase in pressure, but for liquids, it decreases.

a) True

b) False


Material Property

1. Tomato Ketchup i. Bingham model

2. Bentonite ii. Shear thinning

3. Toothpaste iii. Thixotropic

4. Cornstarch + water iv. Shear thickening

a) 1-ii; 2-iv, 3-i, 4-iii

b) 1-ii; 2-iii, 3-i, 4-iv

c) 1-iv; 2-iii, 3-ii, 4-i

d) 1-iv; 2-i, 3-ii, 4-iii

5. In earlier times, hard rocks containing ore veins were broken down by heating the

rock face with a wood fire, then quenching with water to induce crack growth. What is

this phenomenon called?

Thermal shock

6. Which of the following statements are true?

a) Invar is a solid solution of Fe-Ni

b) From 0 to 100oC, Invar has zero coefficient of thermal expansion

c) Invar is used as reference in labs for calibration

d) All of the above

7. In Cu-Zn alloy, increasing the composition of copper will increase the thermal

conductivity of the alloy.

a) True

b) False

ASSIGNMENT-8

1. Match the following.

1. Hard wood i) Conifers

2. Soft wood ii) Region between bark and wood

3. Sap wood iii) Early wood

4. Summer wood iv) Deciduous

5. Inner bark v) Conducts moisture from root

vi) Smaller cambium cells

vii) Living tissue

a) 1-v, 2-i, 3-v, 4-iii, 5-vi

b) 1-iv, 2-iii, 3-v, 4-vi, 5-vii

c) 1-iv, 2-i, 3-v, 4-vi, 5-vii

d) 1-i, 2-v, 3-i, 4-vi, 5-vii

2. With reference to the structure of wood, which of the statement (or statements) is/are

wrong?

a) Formation of green or black knots depends upon whether the cambium of branch is alive or

dead

b) Apart from longitudinal and transversely oriented cells, the softwood also contains pores &

fibres

c) Cellulose fibrils are bonded together by hydrogen bonding only

d) Lignin is the cementing agent which binds cellulose cells together

e) Wood is strong in the direction of growth

a) a & c

b) b, c & e

c) b & c

d) a, c & d

3. The number of independent constants require to understand the elastic behaviour of

steel and wood are

a) 2 and 3

b) 2 and 6

c) 2 and 2

d) 2 and 9

4. Specific gravity of a particular wood specie is inversely proportional to the

mechanical properties of that wood. True/False

a) True

b) False

5. Which of the following statement is wrong?

a) Green wood is less vulnerable to fungi attack.

b) Dry timber is recommended for use in structural applications.

c) Seasoning is the removal of moisture from wood with or without causing distortion.

a) A only

b) b & c

c) a & c

d) c only

6. Assertion (A): Strength of wood increases due to seasoning

Reason (R): During seasoning bound water between cells was removed and this leads to

reduced inter atomic distance (r) and subsequently the attractive force

(F=α1α2/r6) increases

a) Both A and R are correct and R is correct explanation for A

b) Both A and R are correct but R is not correct explanation for A

c) A is wrong and R is correct

d) A is correct and R is wrong

7. With reference to the following figure, which of the below given statement (or

statements) is/are wrong?

a) "O" is called fibre saturation point

b) "OB" corresponds to the removal bound water

c) "OA" corresponds to the removal of bound water and shrinkage

d) In the region of "OB" cell walls are still saturated

8. Wood exhibits differential shrinkage. What is the descending order of various

shrinkage's as per their magnitude

(Refer the following figure. Treat L, R and T as Longitudinal shrinkage, Radial

shrinkage and Tangential Shrinkage)

a) R>T=L

b) T>R=L

c) T>R>L

d) R>T>L

9. With reference to the Engineering properties of wood, which of the following is not

correctly matched

Engg. Property Highest in Lowest in

i) Coefficient of variance Work to max. Load Specific gravity

ii) Elastic modulus (E) Longitudinal direction Tangential direction

iii) Tensile strength Perpendicular to grain Parallel to grain

iv) Comp. strength Perpendicular to grain Parallel to grain

a) iv only

b) iii &i

c) iv & iii

d) iii only

10. Match the following Engg. properties of wood with their failure mechanisms

a) Tensile strength perpendicular to grain i) Rupture of bottom fibres

b) Tensile strength parallel to grain ii) Separation of micro-fibrils

c) Tensile strength in bending iii) Buckling of cell walls

d) Comp. strength Parallel to grain iv) Breaking of secondary bonds

e) Comp. strength perpendicular to grain v) Breaking of primary bonds

f) Shear strength parallel to grain vi) Collapsing of cells

a) a-v, b-ii, c-i, d-iii, e-iv, f-vi

b) a-iv, b-vi, c-i, d-iii, e-v, f-ii

c) a-ii, b-v, c-i, d-iii, e-vi, f-iv

d) a-ii, b-i, c-iii, d-iv, e-v, f-vi

11. If the modulus of rupture of a wood is 80 MPa in green state, what might be the

modulus of rupture (in MPa) at 12% moisture content?

a) 80

b) 82

c) 100

d) 75

12. Thermal conductivity of wood is directly proportional to the specific gravity of the

wood. True/False?

a) True

b) False

13. Timber can maintain its strength with temperature better than steel and concrete.

The key factor/factors contributing to this is/are:

i) Temperatures beyond 100 0C are necessary for self-ignition.

ii) Formation of char prevents incoming convective heat and protects inner un-burnt timber.

iii) Temperatures beyond 500 0C are necessary for self-ignition in absence of fire.

iv) Failure occurs only when burnt material is lost.

a) i and iii

b) ii and iv

c) iii and ii

d) iv only

14. Grade of plywood is determined by the type of adhesive used in its manufacturing

process. True/False?

a) True

b) False

15. With reference to the Pre-pressing of veneers in plywood making, which of the

statement is wrong

a) Purpose of pre-pressing is to equally distribute the moisture across the plywood

b) Both heat and pressure are involved

c) By doing this, wraps in end product can be eliminated

d) This should be done after spreading the glue on veneers

ASSIGNMENT-9

1. Polypropylene can be easily melted when compared to Polyethylene

a) True

b) False

2. Which of the following is true when it comes to forming process of FRP

A. Pultrusion

B. Mandrel wrapping

C. Compression moulding

a) Only A and B are true

b) Only A and C are true

c) All are false

d) All are true


A. Geomembranes 1. Soil reinforcement

B. Geotextile 2. Anchor for sheet wall structures to soil

C. Geogrid 3. Tunnel lining

D. Geo linear elements 4. Reservoir

a) A-2, B-3, C-4, D-1

b) A-3, B-4, C-1, D-2

c) A-4, B-3, C-2, D-1

d) A-1, B-4, C-2, D-3

4. In Elastomeric response of thermoplastic polymers, the entire stress is recovered

on removal of strain.

a) True

b) False

5. Polymer is said to be viscous when T<Tg

a) True

b) False

6. Which of the following statement is incorrect for Fiber Reinforced Polymer (FRP)

a) Glass reinforced polymers are strongest and most resistive to deforming forces when

the polymers fibres are perpendicular to the force being exerted.

b) There are no sufficient codes for the use of FRP in strengthening

c) FRP strengthening is expensive

d) Slabs may be strengthened by applying FRP strips at their bottom face

7. Glass fiber is more tensile than steel fiber

a) True

b) False


A. Glass fibre reinforced polymer 1. Kevlar

B. Aramid fibre reinforced polymer 2. Good compressive strength

C. Carbon fibre reinforced polymer 3. Good heat resistance

a) A-2, B-3, C-1

b) A- 3, B-1, C-2

c) A-1, B-3, C-2

d) A-3, B-2, C-1

ASSIGNMENT-10

1. Hot working technique of metal forming involves in the contraction of dimensions on

cooling. True/False

a) True

b) False

2. Which of the following statement/statements is/are incorrect regarding metal forming

and joining techniques

a. Exposure of hot metal to air because heavy oxidation film on surface

b. Cold working creates large amounts of dislocations

c. In poly-crystalline metals, cold working produces isotropy

d. Joining material for welding should have properties better than parent metal

e. Filler material melts at lower temperatures in brazing than in soldering

a) b & d

b) c & e

c) b & e

d) only b

3. Match the following in the context of Dry oxidation

a. Oxide occupies lesser volume than metal i. Prevents further oxidation

b. Oxide occupies more volume than metal ii. Shrinkage & cracking

c. Insignificant volume change iii. Fall off

a) a-i, b-ii, c-iii

b) a-ii, biii, c-i

c) a-i, b-iii, c-ii

d) a-ii, b-i, c-iii

4. In the absence of O2 and presence H2O corrosion occurs. True/False

a) True

b) False

5. The following figure shows the elevation of a RC beam whose bottom surface is

subjected to chloride attack. In this context, identify the four components (C-cathode,

A-anode, E-electric conductor and I-ionic conductor) of wet corrosion

a) C-top rebar, A-bottom rebar, E-surrounding concrete, I-stirrups

b) C-bottom rebar, A-top rebar, E-surrounding concrete, I-stirrups

c) C-top rebar, A-bottom rebar, E-stirrups, I-surrounding concrete

d) C-top rebar, A-stirrups, E-surrounding concrete, I-bottom rebar

6. Which of the following statement/statements is/are correct regarding corrosion

prevention

a. Ni, Ti are mostly selected for corrosion resistance as they produce protective oxide films

b. Sacrificial anode can serve large areas

c. Non-cathodic coatings leads to formation of corrosion cells with high anode to cathode

ratio

d. Insufficient dosage of inhibitors results in enhanced corrosion

a) a, c & d

b) a, b & d

c) a & d

d) b & c

7. Two compositions A & B of pearlitic grey cast iron are given below. Among these two

which composition represents "Ductile iron" and which component is responsible for

ductility?

A - 3.4 wt % of C, 2.5 wt % of Si, 0.01 wt % of P

B - 3.4 wt % of C, 2.5 wt % of Si, 0.01 wt % of P and 0.03 wt % of Mg

a) B and P

b) A and P

c) B and Mg

d) A and C


a. Carbon steel i. Carbon content up to 0.25%

b. Mild steel ii. Presence of elements other than Mn& Si

c. Stainless steel iii. Carbon content between 0.3% to 0.6%

d. Alloy steel iv. Ferrite & Fe3C phases

v. Contains Cr & Ni

a) a-ii, b-i, c-v, d-iii

b) a-iii, b-i, c-v, d-ii

c) a-ii, b-i, c-v, d-ii

d) a-iii, b-i, c-ii, d-v

9. High carbon contents in steel results in good toughness. True/False?

a) True

b) False

10. Which of the following statement is wrong in relation to the micro structure of TMT

bar in Tampering stage?

a) Core transforms to ferrite & Pearlite

b) Surface is of tampered matensite

c) Core is composed of Austenite before this stage

d) This tampering happens after quenching stage


a. External Al layers with alternate Bituminous layers i. Sacrificial anode

b. Copper ii. High strength to weight ratio

c. zinc iii. Insulated roof

d Titanium iv. Anti-microbial in nature

v. Anodizing

a) a-v, b-iv, c-ii, d-i

b) a-iii, b-iv, c-ii, d-v

c) a-iii, b-iv, c-i, d-ii

d) a-v, b-iv, c-i, d-ii

ASSIGNMENT-11


1 Emusified bitumen A. used as binder in cold mix asphalt

2 Zeolite B. has high air void content

3 Foamed bitumen C. reduces the temperature required in hot mix asphalt

4 Cold mix asphalt D. uses two binders - soft & hard bitumen

5 Warm mix asphalt E. used to increase fluidity in warm mix asphalt

a) 1-C; 2-E; 3-A; 4-B; 5-D

b) 1-C; 2-A; 3-E; 4-D; 5-B

c) 1-E; 2-A; 3-C; 4-B; 5-D

d) 1-A; 2-C; 3-E; 4-D; 5-B

2. Denser grading of aggregates ensures

A. Better stability

B. Better flexibility

C. Better fatigue resistance

D. Prevents rutting

a) Only A & D are true

b) Only A & B are true

c) Only A & C are true

d) A, C & D are true

e) All are true

3. Which of the following statements is incorrect?

I Cracking occurs at high temperatures

II Rutting occurs at high viscosity

III Rutting is identified by ditches formed perpendicular to the direction of traffic

IV Cracking can lead to pattern type cracking

a) All of the above

b) I & III only

c) I only

d) II & III only

e) III only

4. Two samples of bitumen, Sample A and Sample B are tested for penetration grade.

Sample A has a penetration value of 10 mm and Sample B has a penetration value of 7

mm. Which sample has better potential for resisting cracking at low temperature?

a) Sample A

b) Sample B

5. Bitumen can be represented as a colloid where _____ are the solid particles in the

form of micelles, dispelled in _____, with _____ forming the interface.

Asphaltenes, oils, resins

6. Which of the following is least favourable condition for asphalt-bitumen bond?

a) Complete wetting of surface of the aggregates by bitumen

b) A thin layer of bitumen surrounds the aggregates

c) Aggregates are moist when bitumen is added

d) Aggregates having rough surfaces are used

ASSIGNMENT-12

1. The following pie chart shows the cement composition. Identify the components A, B,

C, D& E.

a) A-SiO2, B- CaO, C-Al2O3, D-MgO& E-Fe2O3

b) A-SiO2, B- CaO, C-Al2O3, D-Fe2O3 & E-MgO

c) A-CaO, B-SiO2 , C-Al2O3, D-MgO& E-Fe2O3

d) A-CaO, B-SiO2 , C-Al2O3, D-Fe2O3 & E-MgO

2. With the help of following figure, match the following.

a) Peak I i. Rapid dissolution of C3S

b) Peak II ii. Ettringite to Monosulfoaluminite transition

c) Peak III iii. Heat of wetting

d) T iv. Dormant period

a) a-ii, b-i, c-iii, d-iv

b) a-iii, b-ii, c-i, d-iv

c) a-iii, b-i, c-ii, d-iv

d) a-ii, b-iii, c-i, d-iv

3. What is the ascending order of the following parameters related to Hydrated Cement

Paste according to their dimensional range?

A - Aggregation of CSH particles

B - Entrapped air void

C- Spacing between CSH sheets

D- Entrained air void

a) C-D-B-A

b) D-C-A-B

c) D-B-A-C

d) C-A-D-B

4. For a deck in metro rail project, contractor used M60 concrete. After the

construction, an investigation was carried out under the deck. The investigation

revealed that there are shrinkage cracks. Which of the following might be the problem

related to mix design?

Use of fibres @ dosage of 15kg/m3

Mass replacement of cement with silicafume

Mass replacement of cement with slag

Mass replacement of cement with flyash

5. Every 1% additional air entrainment into the concrete will leads to 10% reduction in

its strength. True/False?

a) True

b) False

6. Which of the following effects are not common between flyash concrete and

silicafume concrete.

A. Increased setting time

B. Reduction in bleeding

C. More requirement of air-entrained admixture for entraining air into concrete

D. Increased water demand

E. Bad fire performance

F. Higher amounts of creep & shrinkage than normal concretes

a) C, B & D

b) A, D & E

c) A, C & F

d) A, C & E

7. Assertion (A) : Corrosion of steel in concrete results in cracks and spalling.

Reason (R) : Rust has a volume of 2-6 times that of steel and creates expansion in the

concrete.

a) A is false, but R is correct

b) Both A and R are correct, but R is not correct explanation

c) A is correct, but R is false

d) Both A and R are correct, R is correct explanation

8. Which of the following statements are correct in relation to creep and shrinkage of

concrete?

a) Shrkage strains are different in different directions

b) Under the conditions of restrained shrinkage and creep, there will be a reduction in

cracking

c) Creep and shrinkage strains are recoverable

d) To determine the autogeneous shrinkage, the samle should be sealed

a) a & d

b) b & d

c) a, b & c

d) c, b & d

9. Match the following.

a) Water reducers i. Early removal of formwork

b) Set-accelerators ii. Lowers the surface tension of capillary water

c) Steel fibres iii. Dispersion effect

d) Shrinkage reducing admixtures iv. Anti- washout agent for concretes under water

e) Viscosity Modifying Agent (VMA) v. Improved post peak behaviour

a) a-iii, b-i, c-v, d-ii, e-iv

b) a-ii, b-iii, c-iv, d-v, e-i

c) a-iii, b-iv, c-v, d-ii, e-i

d) a-ii, b-i, c-v, d-iii, e-iv

10. Match the following in the context of materials used special concretes?

a) Propylene fibres i. Geopolymer concrete

b) More fines content ii. High strength concrete

c) Sodium Hydroxide iii. Aerated concrete

d) Aluminium powder iv.Self compacting concrete

a) a-ii, b-iv, c-iii, d-i

b) a-iii, b-iv, c-ii, d-i

c) a-ii, b-iv, c-i, d-iii

d) a-iii, b-iv, c-i, d-ii

ASSIGNMENT-13

1. Which of the following is the right sequence during the hydration process?

a) Dormant period, Heat evolution, Steady state, Rapid reaction of alite

b) Heat evolution, Dormant period, Rapid reaction of alite, Steady state

c) Steady state, Dormant period, Heat evolution, Rapid reaction of alite

d) Rapid reaction of alite, Heat evolution, Dormant period, Steady state

2. What happens in flash set reaction in hydration?

a) Aluminates in the absence of gypsum hydrate rapidly to produce calcium-aluminate-

hydrates

b) Silicates hydrate to produce Calcium-silicate-hydrate gel and calcium hydroxide

c) In the presence of gypsum, ettringite and monosulphate are produced

3. What leads to gel formation of Calcium-Silicate-Hydrate?

a) High covalent/ionic and Van der Waals forces

b) C/S ratio of 1.5 to 2

c) High surface area

4. Indicate what does A, B and C marked in the diagram indicate

a) Portland cement, Natural pozzolan, Class C fly ash

b) Natural pozzolan, Portland cement, Class C fly ash

c) Class C fly ash, Portland cement, Natural pozzolan

5. Which type of grading is ideal for a good concrete mix usually?

a) Gap grading

b) Uniform grading

c) Continuous grading


A. Silica

fume

1.Used as replacement to cement largely in India

B. Fly Ash 2. By-product of iron or steel manufacturing

process

C. Bentonite 3. Used in conjunction with a superplasticizer

D. GGBS 4. Used in stabilizing sides of bore holes

a) A-3, B-1, C-4, D-2

b) A-2, B-3, C-4, D-1

c) A-4, B-1, C-2, D-3

d) A-1, B-4, C-2, D-3

7. Which of the following statements is true w.r.t Chemical admixtures

a) Chemical admixtures affect workability mostly

b) Set controlling chemicals are types of Chemical admixtures

c) Also called Supplementary Cementing materials

a) All are true

b) Only A and B are true

c) Only A and C are true

d) Only B and C are true

8. What type of shrinkage is the Concrete protected against when freshly laid concrete

is covered by polythene cover?

a) Autogenous shrinkage

b) Thermal shrinkage

c) Plastic shrinkage

d) Drying shrinkage


A. Sulphate attack 1. Attacks pore fluid of Concrete

B. Carbonation 2. Results in formation of gel

C. Alkali-silicate reaction 3. Destroys cementing effect of Concrete

a) A-3, B-1, C-2

b) A-2, B-3, C-1

c) A-1, B-3, C-2

10. In sulphate attack, the primary products formed are gypsum and ettringite

a) True

b) False

11. Carbonation results in Increase of pH of concrete

a) True

b) False

12. Increase in addition of air entraining admixtures increases the concrete strength

a) True

b) False

13. Moisture and Oxygen both are required for corrosion sustenance

a) True

b) False

ASSIGNMENT-14

1. Damp-proofing is resistance to the passage of water under the hydrostatic pressure.

True/False?

a) True

b) False

2. Which of the following statement/statements is/are correct in relation to the water

proofing

1. Brick bat coba system is flexible

2. Leakage, Seepage and Dampness are distinguished baed on the quantum of flow

3. Seepage refers to continuous flow of water

4. Visible moisture which can be felt by palm is an indication of dampness

a) 1, 2 & 3

b) 2 & 3

c) 2 & 4

d) 2, 3 & 4


1. External waterproofers a. Pore blockers

2. Internal waterproofers b. Membranes and coatings

3. PVC waterstops c. Water proofing material for construction joints

4. Polyurethane injection d. Arrests the crack

a) 1- a, 2-b, 3-c, 4-d

b) 1- b, 2-a, 3-c, 4-d

c) 1-d , 2-a, 3-c, 4-b


1. Epoxy flooring a. Industrial applications

2. PU flooring b. self-levelling

3. Densipolished flooring c. Use of Lithium Silicate

4. Deck flooring d. Dissipates eddy currents developed

5. ESD flooring e. Anticarbonation floor

a) 1-b, 2-a, 3-c, 4-e, 5-d

b) 1-b, 2-e, 3-a, 4-d, 5-c

c) 1-a, 2-b, 3-c, 4-d, 5-e

d) 1-a, 2-d, 3-c, 4-e, 5-d

5. Aromatic PU floors are used for exterior applications because they have high

resistance to UV radiation. True/False?

a) False

b) True

6. Failure of anchor system due to closely spaced anchors is called......?

a) Concrete breakage

b) Concrete Splitting

7. Identify the incorrect statement in relation to mechanism of anchors

a) The Bonding force decides the force T2

b) The diameter of anchor decides the force T2

c) As the nut gets tightened, the sleeve opens up and friction force develops

d) Friction decides the tension capacity T1

8. Which of the following is incorrectly matched

a) PROFIS Anchors - a software, which gives size of insert plate for connection between

RCC member and steel; Rebarring with splice - Load transfer by Strut & tie model

b) PROFIS Anchors - a software, which gives anchor force for connection between RCC

member and steel; Rebarring with splice - Load transfer by Strut & tie model

c) PROFIS Rebar - a software, which gives the dowel bars details for connection

between RCC members; Rebarring without splice - Load transferred is equal to

Concrete cone capacity

july november, 2015 · 2017-08-04 · modern construction materials (noc15-ce05) nptel online...

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