Question 1 |

The softening point of bitumen has the same unit as that of

distance | |

temperature | |

time | |

viscosity |

Question 1 Explanation:

Softening point is the temperature at which bitumen becomes soft and starts flowing.

Question 2 |

Group-I gives a list of test methods for evaluating properties of aggregates. Group-II
gives the list of properties to be evaluated.

The correct match of test methods under Group-I to properties under Group-II, is

The correct match of test methods under Group-I to properties under Group-II, is

P-4, Q-1, R-2, S-3 | |

P-2, Q-1, R-4, S-3 | |

P-3, Q-4, R-1, S-2 | |

P-2, Q-4, R-3, S-1 |

Question 2 Explanation:

Soundness test is done to evaluate
resistance against weathering of aggregate.

Crushing test is done to evaluate strength of aggregate.

Los angles abrasion test is to evaluate hardness of aggregate.

Stripping value test is to evaluate ratio of uncovered area observed to the total area of aggregate. The test is conducted to determine the effects of moisture upon the adhesion of binding material.

Crushing test is done to evaluate strength of aggregate.

Los angles abrasion test is to evaluate hardness of aggregate.

Stripping value test is to evaluate ratio of uncovered area observed to the total area of aggregate. The test is conducted to determine the effects of moisture upon the adhesion of binding material.

Question 3 |

The Los Angeles test for stone aggregates is used to examine

abrasion resistance | |

crushing strength | |

soundness | |

specific gravity |

Question 3 Explanation:

Los Angles abrasion test is carried out to
examine the hardness i.e., abrasion resistance
property of aggregate

Question 4 |

Structural failures considered in the mechanistic method of bituminous pavement design are

Fatigue and Rutting | |

Fatigue and Shear | |

Rutting and Shear | |

Shear and Slippage |

Question 5 |

The initial concavity in the load-penetration curve of a CBR test is NOT due to

uneven top surface | |

high impact at start of loading | |

inclined penetration plunger | |

soft top layer of soaked soil |

Question 5 Explanation:

Initial concavity in CBR test due to

Improper compaction.

Soft top layer

Inclined plunger

Improper compaction.

Soft top layer

Inclined plunger

Question 6 |

A bitumen sample has been graded as VG30 as per IS : 73-2013. The '30' in the grade means that

penetration of bitumen at 25^{\circ}C is between 20 and 40 | |

viscosity of bitumen at 60^{\circ}C is between 2400 and 3600 Poise | |

ductility of bitumen at 27^{\circ}C is more than 30 cm | |

elastic recovery of bitumen at 15^{\circ}C is more than 30% |

Question 7 |

The following observations are made while testing aggregate for its suitability in pavement construction:

i. Mass of oven-dry aggregate in air = 1000 g

ii. Mass of saturated surface-dry aggregate in air = 1025 g

iii. Mass of saturated surface-dry aggregate under water = 625 g

Based on the above observations, the correct statement is

i. Mass of oven-dry aggregate in air = 1000 g

ii. Mass of saturated surface-dry aggregate in air = 1025 g

iii. Mass of saturated surface-dry aggregate under water = 625 g

Based on the above observations, the correct statement is

bulk specific gravity of aggregate = 2.5 and water absorption = 2.5 % | |

bulk specific gravity of aggregate = 2.5 and water absorption = 2.4 % | |

apparent specific gravity of aggregate = 2.5 and water absorption = 2.5% | |

apparent specific gravity of aggregate = 2.5 and water absorption = 2.4 % |

Question 7 Explanation:

Bulk specific gravity =\frac{A}{B-C}

Apparent specific gravity =\frac{A}{A-C}

Where,

A= Mass of oven dry aggregate in air

B= Mass of Saturated surface dry aggregate in air

C= Mass of Saturated surface dry aggregate under water

\therefore Bulk specific gravity

=\frac{1000}{1025-625}=\frac{1000}{400}=2.5

Water absorption

=\frac{1025-1000}{1000} \times 100=2.5 \%

Apparent specific gravity =\frac{A}{A-C}

Where,

A= Mass of oven dry aggregate in air

B= Mass of Saturated surface dry aggregate in air

C= Mass of Saturated surface dry aggregate under water

\therefore Bulk specific gravity

=\frac{1000}{1025-625}=\frac{1000}{400}=2.5

Water absorption

=\frac{1025-1000}{1000} \times 100=2.5 \%

Question 8 |

During a forensic investigation of pavement failure, an engineer reconstructed the graphs P, Q, R and S, using partial and damaged old reports.

Theoretically plausible correct graphs according to the 'Marshall mixture design output' are

Theoretically plausible correct graphs according to the 'Marshall mixture design output' are

P, Q, R | |

P, Q, S | |

Q, R, S | |

R, S, P |

Question 8 Explanation:

The graph between VFB and Bitumen content is,

Question 9 |

In Marshall method of mix design, the coarse aggregate, fine aggregate, fines and bitumen having respective values of specific gravity 2.60, 2.70, 2.65 and 1.01, are mixed in the relative proportions (% by weight) of 55.0, 35.8, 3.7 and 5.5 respectively. The theoretical specific gravity of the mix and the effective specific gravity of the aggregates in the mix respectively are:

2.42 and 2.64 | |

2.42 and 2.78 | |

2.42 and 2.93 | |

2.64 and 2.78 |

Question 9 Explanation:

Theoretical specific gravity,

\begin{aligned} G_{t} &=\frac{w_{1}+w_{2}+w_{3}+w_{4}}{\frac{w_{1}}{G_{1}}+\frac{W_{2}}{G_{2}}+\frac{W_{3}}{G_{3}}+\frac{W_{4}}{G_{b}}} \\ &=\frac{55+35.8+3.7+5.5}{\frac{55}{2.6}+\frac{35.8}{2.7}+\frac{3.7}{2.65}+\frac{5.5}{1.01}}+ \\ &=2.42 \end{aligned}

Effective specific gravity of aggregates (coarse + fine) is given by,

\begin{aligned} G^{\prime} &=\frac{(55 \times 2.6)+(35.8 \times 2.7)}{55+35.8} \\ &=2.639=2.64 \end{aligned}

\begin{aligned} G_{t} &=\frac{w_{1}+w_{2}+w_{3}+w_{4}}{\frac{w_{1}}{G_{1}}+\frac{W_{2}}{G_{2}}+\frac{W_{3}}{G_{3}}+\frac{W_{4}}{G_{b}}} \\ &=\frac{55+35.8+3.7+5.5}{\frac{55}{2.6}+\frac{35.8}{2.7}+\frac{3.7}{2.65}+\frac{5.5}{1.01}}+ \\ &=2.42 \end{aligned}

Effective specific gravity of aggregates (coarse + fine) is given by,

\begin{aligned} G^{\prime} &=\frac{(55 \times 2.6)+(35.8 \times 2.7)}{55+35.8} \\ &=2.639=2.64 \end{aligned}

Question 10 |

Match the information related to test on aggregates given in Group-I with that in Group-II.

P-1, Q-3, R-4, S-2 | |

P-3, Q-1, R-4, S-2 | |

P-4, Q-1, R-3, S-2 | |

P-3, Q-4, R-2, S-1 |

There are 10 questions to complete.