1. What is used as a charge for the Los Angeles abrasion test?
a) Electric supply
b) Steel balls
c) Aggregates
d) Drum
Explanation: The materials used to subject the sample to abrasion is termed as a charge. In the Los Angeles test, steel balls are used as the charge. Aggregates are the sample to be tested, the machine is powered electrically and the drum is the machine inside which the sample and charge are rotated.
2. Soundness test is carried out by conducting the accelerated weathering test cycle.
a) true
b) false
Explanation: Soundness test is used to evaluate the weathering action on the aggregates. In order to replicate the wet/dry and freeze/thaw cycles in the laboratory, the accelerated weathering test cycle is made use of.
3. which of the below IS code – test pairs have been matched incorrectly?
a) IS 2386 part 1 – shape test
b) IS 2386 part 5 – hardness
c) IS 2386 part 4 – toughness
d) IS 2386 part 5 – crushing
Explanation: IS 2386 part 4 is used for details on crushing and toughness tests on aggregates. IS 2386 part 5 is used for hardness and durability test. IS 2386 part 1 is used to follow guidelines for shape test.
4. A sample having stripping value as 0% cannot be used for pavement construction.
a) true
b) false
Explanation: Stripping value is examined visually and is taken as the ratio of stripped area to the original area. If the binder coating has not come off, then the stripped area is 0, so is the stripping value. It indicates good adhesion and can be used for constructing pavement.
5. Tar is no longer used as a binder in pavements because of its ______
a) Durability
b) Viscosity
c) Temperature susceptibility
d) Colour change
Explanation: The binder used are bitumen and tar. The colour of tar is black, it has similar viscosity and durability to the bitumen. The problem is the high temperature susceptibility. Also, it results in the release of harmful fumes when it is heated.
6. Which of the below is not a type of bitumen used in the construction of flexible pavements?
a) Oxidised bitumen
b) Cut-back bitumen
c) Modified bitumen
d) Bitumen emulsion
Explanation: Oxidised bitumen is prepared by oxidizing the refined bitumen. This reduces its ductility and can be used for non-road applications. It is employed for use in paints, roofing, adhesives, etc.
7. Bitumen is classified as hard and thin based on ______
a) Application
b) Source
c) Viscosity
d) Strength
Explanation: Bitumen is classified into hard and thin bitumen based on their application. Thin bitumen is used for road applications and hard bitumen is used for non-road applications like in paints, sealants, etc.
8. What does PMB stand for?
a) Polymer Modified Bitumen
b) Polymer Mix Bitumen
c) Penetration Modified Bitumen
d) Penetration Mix Bitumen
Explanation: PMB stands for Polymer Modified Bitumen. These are produced by adding polymers like styrene-butadiene-styrene (SBS), SBR, polyethylene, etc. The polymers help in modifying the properties of bitumen.
9. The paving grade bitumen is susceptible to temperature changes.
a) true
b) false
Explanation: The ordinary paving grade bitumen is susceptible to temperature changes. The road pavements become softer in summer and brittle in winter. This can be solved by adding modifiers to the bitumen.
10. The grades of bitumen used for non-road applications are called as ______ grade bitumen.
a) Market
b) Industrial
c) Oxidation
d) Commercial
Explanation: There are two grades of bitumen based on application – one for road construction purpose and one for waterproofing structures. Paving grade bitumen is used for road construction purpose and industrial grade bitumen is used for other works.