Highway Engineering MCQs on “Stone aggregates – 2”.
1. Aggregates obtained from which type of rocks are strong?
a) Igneous
b) Sedimentary
c) Metamorphic
d) Rocks formed by weathering
Answer: a
Clarification: Aggregates that are obtained from igneous rocks are strongest they include granite, basalt. Sedimentary are obtained from igneous rocks and metamorphic from igneous and sedimentary so they are not so strong.
2. What is the maximum size that can be used in plain concrete?
a) 40 mm
b) 20 mm
c) 100 mm
d) 80 mm
Answer: d
Clarification: The maximum size of aggregate that can be used in plain concrete is 80mm with ease of workability, however they exceed in some special cases up to 100 mm, mostly 20 mm aggregate is used in RCC and 40 mm in pavements.
3. What is the maximum size of aggregate that can be used in R.C.C?
a) 10mm
b) 15mm
c) 20mm
d) 25mm
Answer: c
Clarification: The maximum size of aggregates used in RCC is limited to 20mm, for ease of compaction and workability, however 10 mm, 15 mm are also used, in some exceptions 25 mm also is used.
4. The flaky aggregates should not exceed __________
a) 1/2 of mean dimension
b) 3/4th of mean dimension
c) 3/5th of mean dimension
d) 1/8th of mean dimension
Answer: c
Clarification: The flaky aggregate is usually considered as 3/5th of its mean lateral dimension, the flaky aggregates should not be used in pavements.
5. The factors which effect the formation of metamorphic rocks are?
a) Heat
b) Pressure
c) Heat and pressure
d) Molten lava
Answer: c
Clarification: Metamorphic rocks are obtained both from sedimentary and igneous rocks, which are influenced by factors like heat and pressure.
6. The fine aggregates are having a size less than __________
a) 5mm
b) 4.75mm
c) 2.36 mm
d) 75 microns
Answer: b
Clarification: If the sieve size of aggregates less than 4.75mm, then it is called as fine aggregate. If it exceeds 4.75 mm it is gravel, if it is less than 75 microns it is a fine grain soil.
7. Which type of aggregates gives good workability?
a) Round
b) Flaky
c) Angular
d) Irregular
Answer: a
Clarification: The aggregates which gives more ease of working and workability is round aggregate, flaky and angular also used in some cases, irregular also are used in pavements.
8. If the bulk density of an aggregate is 2.6kg/lit and Gs is 2.8 then, the percentage of voids is __________
a) 7.1
b) 71
c) 710
d) 0.71
Answer: a
Clarification: Percentage of voids=G-Ὑ/G
=2.8-2.6/ (2.8)
=7.14%.
9. The dividing and operating of aggregates into different sizes is called __________
a) Sieve analysis
b) Gap grading
c) Impact
d) Hardness
Answer: a
Clarification: The operating and division of the aggregates as per size is called as sieve analysis, in which the particles are divided as per size, gap grading is a part of the graph drawn in sieve analysis.
10. The expansion of aggregate on reaction with water is called __________
a) Swelling
b) Bulking
c) Expelling
d) Breaking
Answer: b
Clarification: If the aggregate reacts with water and its volume increase then it is called as bulking, swelling is absorption of water, expelling is the removal of water, and breaking is a complete failure.
11. The skid resistance is measured in __________
a) Swedish pendulum number
b) British pendulum number
c) Indian pendulum number
d) Friction coefficient
Answer: b
Clarification: The skid resistance of the pavement is measured in British pendulum number, which is obtained just by rubbing the material with equipment.
12. Which material can be replaced in concrete for a strong pervious concrete pavement?
a) Water
b) Course aggregate
c) Fine aggregate
d) Cement
Answer: b
Clarification: Apart from replacement, there are many materials that can be used for substitution, for a strong pervious concrete pavement better option is to replace coarse aggregate.
13. The minimum grade of concrete required for pavement design is __________
a) M30
b) M35
c) M40
d) M45
Answer: c
Clarification: The minimum grade of concrete required for pavement is M40 as it has to resist both wheel loads and weathering action, M30 for low volume roads, M45 may be more helpful.
14. The aggregates which do not have sufficient strength like waste bricks can be used in __________
a) Base
b) Shoulder
c) Surface
d) Footpath
Answer: d
Clarification: The aggregates which don’t have sufficient strength can be used in footpath as it is not so important component, surface and shoulder use gravel, base mostly requires high strength soil.
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