1. The presence of air voids will result in ______ specific gravity and indicate ______ strength characteristics.
a) Lower, lower
b) Lower, higher
c) Higher, higher
d) Higher, lower
Explanation: The air voids or pores present in the stones will decrease the specific gravity and that indeed will decrease the strength and durability of stone aggregates. Specific gravity is related to the density. The increase in air voids will lower the density, which will, in turn, reduce the specific gravity.
2. Toughness is defined as the resistance to ______
a) Deformation
b) Impact
c) Abrasion
d) Friction
Explanation: Toughness is a property of the aggregate that is a measure of the resistance against impact. Impact on the pavement is subjected by the heavy moving traffic. Resistance to deformation and friction are necessary to provide a smooth and comfortable riding surface. Resistance to abrasion is measured by the hardness property.
3. Which of the below is not a factor that affects the durability property?.
a) Ageing of bitumen
b) Adhesion
c) Movement of traffic
d) Permeability
Explanation: Movement of traffic is a factor that affects the abrasion property. It is responsible for the wearing of the pavement surface. Ageing of bitumen, permeability and adhesion are all factors that affect the durability property. These are responsible for the weathering of the pavement.
4. Which of the below is not a type of soft aggregate?
a) Gravel
b) Crushed brick
c) Slag
d) Laterite
Explanation: Soft aggregates are the ones having less strength compared to hard aggregates. The hard aggregates consist of crushed stones, gravel that have high strength property. Soft aggregates include moorum, kankar, brick aggregates, laterite and slag.
5. Which of the below igneous rocks exhibit good hardness when used as a road aggregate?
a) Granite
b) Basalt
c) Shale
d) Marble
Explanation: Granite and basalt are the types of igneous rocks, out of which basalt exhibits good hardness property. Shale is a type of sedimentary rock and marble is a type of metamorphic rock.
6. Which of the below is supposed to be present in the aggregate?
a) Flaky pieces
b) Angular pieces
c) Rounded pieces
d) Elongated pieces
Explanation: If the pieces of the aggregate are too flaky or elongated, they will be easily crushed when subjected to compaction by roller and also under heavy loads. Rounded pieces possess good strength but don’t have proper interlocking, so angular pieces are preferred.
7. Which of the below accelerates the smoothening of pavement surface?
a) Water
b) Fines
c) Aggregates
d) Vehicle
Explanation: The fine particles like sand and dust are present between tyres of the vehicle and the pavement surface. When the vehicle moves, the fines provide a grinding effect on the surface and aid in the smoothening process.
8. Specific gravity is considered to be a measure of the strength or quality of a material.
a) true
b) false
Explanation: Specific gravity is related to the density of the material. If the specific gravity is less, then the material is found to be weaker. A weak material will have lesser quality compared to a stronger material.
9. The process of coating the aggregates with the binder is largely controlled by ______ of the binder.
a) Viscosity
b) Durability
c) Penetration
d) Surface tension
Explanation: Viscosity is the important property that controls the coating of aggregate with the binder. If the viscosity is high, the coating will be slower. Viscosity is dependent on temperature and it is low at higher temperatures.
10. The polished stone value test is used to test which of the below properties?
a) Roundness
b) Crushing
c) Abrasion
d) Durability
Explanation: The polished stone value test is used to test the abrasion of the pavement. It gives a measure of the friction in the pavement also. Roundness can be tested using the shape test, crushing by crushing test and durability by soundness test.