← Junior Engineer
Past Questions
The presence of which of the following substances in water or aggregate beyond permissible limit can cause corrosion of steel in an RCC members:-
A)
Chlorides
B)
Sulphates
C)
Nitrates
D)
Phosphates
Chlorides are the main cause of corrosion of steel in RCC. If chlorides are present in water or aggregates beyond the permissible limit, they destroy the protective passive film on reinforcing steel and initiate rusting, leading to expansion, cracking, and loss of bond in concrete. Sulphates mainly cause sulphate attack on concrete (expansion and deterioration of cement paste), not direct steel corrosion. Nitrates are not a typical cause of reinforcement corrosion in RCC. Phosphates are generally not associated with corrosion of steel in RCC at the levels considered in standard exam context.
Which of the followings would be an example of compaction:-
A)
A clay strata gets compressed under the pressure of a structure built on it
B)
A fill gets compressed under its own weight
C)
Reduction of voids produced during the construction of an earth dam
D)
Both (a) & (c) are correct
Compaction is the densification of soil by mechanical means, typically during construction, which reduces air voids and increases dry density. Option (c) is correct because reduction of voids during the construction of an earth dam is a classic example of compaction. Option (a) is incorrect because compression of a clay stratum under a structure is consolidation, not compaction; it occurs due to expulsion of pore water under sustained load. Option (b) is also incorrect because a fill compressed under its own weight is settlement/consolidation, not deliberate compaction. Therefore, only (c) is an example of compaction, so (d) is false.
One of the purposes of Rain water harvesting and conservation is to:-
A)
Enhance the quantity of surface run-off to Rivers or Streams
B)
Help maximize the evaporation loss for hydrologic cycle
C)
Augment the sustainable yield of Ground water
D)
Prevent excessive waste of water supply by the consumers
Rainwater harvesting and conservation aim to capture, store, and recharge rainwater so it can be used later and to improve groundwater availability. Therefore, the correct purpose is to augment the sustainable yield of groundwater.
Why the others are incorrect:
- d: Preventing waste of water by consumers is a general water-use efficiency measure, not the main purpose of rainwater harvesting.
- b: Maximizing evaporation loss is the opposite of conservation; harvesting seeks to reduce losses and retain water.
- a: Enhancing surface runoff to rivers or streams is not a goal; rainwater harvesting reduces runoff by collecting or infiltrating water.
Choose the most important force from the following causes of failure of slopes:-
A)
Seepage water
B)
Earthquakes
C)
Gravity
D)
Flowing water
Gravity is the primary and most important force responsible for slope failure because it acts continuously on the mass of soil or rock, driving it downslope and creating the shear stress that can exceed the resisting shear strength. Without gravity, slope instability would not occur in the usual sense.
Why the others are not the main cause:
- Seepage water: It can reduce effective stress and weaken slopes, but it is a contributing factor rather than the fundamental driving force.
- Flowing water: It may erode the toe of a slope or trigger local instability, but it is not the principal force causing slope failure.
- Earthquakes: They can trigger landslides by shaking and temporarily reducing stability, but they are occasional triggering agents, not the basic permanent force acting on all slopes.
The economical height for the construction of re-inforced earth wall generally considered is:-
A)
less than 4m
B)
4m to 5m
C)
less than 5m
D)
more than 5m
The economical height for a reinforced earth wall is generally taken as about 4 m to 5 m. Below this range, conventional retaining walls are often more economical; above this range, reinforced earth construction becomes increasingly cost-effective due to reduced material and foundation requirements. Hence option (b) is correct.
Why the others are incorrect:
- (a) less than 4 m: too low; reinforced earth walls are usually not the most economical choice for such small heights.
- (c) less than 5 m: too broad and not the standard economical range; it includes heights where the choice may not be economical.
- (d) more than 5 m: incorrect because reinforced earth walls are generally economical from around 4 m upward, not only beyond 5 m.
The punching shear mode of failure of soil under foundation occurs in:-
A)
Very dense sand
B)
Dense sand
C)
Relatively loose sand
D)
Very loose sand
Punching shear failure occurs in relatively loose, compressible soils where the footing tends to punch downward with little lateral soil heave. This mode is typical of loose sand (and soft clays), because the soil has low density and low shear resistance, so failure is localized beneath the foundation.
Why others are incorrect:
- a) Very dense sand: usually shows general shear failure, not punching shear, because it has high strength and pronounced failure surfaces.
- b) Dense sand: also tends toward general shear failure due to higher friction and stiffness.
- d) Very loose sand: while very loose sand is weak, standard bearing-capacity classification associates punching shear with relatively loose sand; very loose sand is more often treated as an extreme loose condition rather than the usual textbook category for punching shear.
The maximum height beyond which Random Rubble Dry masonry Retaining wall should be avoided unless it is unavoidable is:-
A)
5m
B)
6m
C)
8m
D)
10m
The correct answer is **6 m**. In practice, **random rubble dry masonry retaining walls** are generally recommended only up to about **6 m height** because dry masonry has no mortar bond, so its strength and stability against sliding, overturning, and seepage are limited. Beyond this height, the wall becomes uneconomical and unsafe unless special circumstances make it unavoidable.
Why the other options are incorrect:
- **5 m (a):** Too low; dry rubble retaining walls can commonly be used beyond 5 m in suitable conditions.
- **8 m (c):** Exceeds the usual safe/standard limit for dry masonry retaining walls.
- **10 m (d):** Much too high for random rubble dry masonry; such heights would normally require a more robust retaining structure, often with mortar or reinforced concrete.
Hence, the maximum height beyond which random rubble dry masonry retaining walls should be avoided is **6 m**.
Any man made scheme or facility that adds water to an aquifer is referred to as:-
A)
Percolation
B)
Recharge
C)
Precipitation
D)
Sedimentation
The correct answer is **Recharge**. In hydrology, any natural or man-made process or facility that adds water to an aquifer is called **groundwater recharge**. Artificial recharge schemes are specifically designed to increase the amount of water entering groundwater storage.
Why the others are incorrect:
- **Precipitation**: This is water falling from the atmosphere as rain, snow, etc.; it is not the term for adding water to an aquifer.
- **Sedimentation**: This refers to the settling of suspended particles, not groundwater replenishment.
- **Percolation**: This is the movement of water through soil or porous material, which may contribute to recharge, but it is not the name of the man-made scheme/facility itself.
The dead storage in water tank is meant mainly to:-
A)
reserve water for emergency situation
B)
keep the floor of the tank wet at all time for curing purpose
C)
regulate pressure due to water level fluctuation
D)
assist settling of silt
Dead storage is the portion of water stored below the outlet level and is not normally available for use. Its main purpose is to allow suspended impurities and silt to settle at the bottom, so the usable water remains clearer. Hence, option d is correct. Option a is incorrect because emergency reserve is a function of reserve storage, not dead storage. Option b is incorrect because keeping the tank floor wet for curing is not a storage function. Option c is incorrect because pressure regulation due to water level fluctuation is related to service/storage operation, not dead storage.
For the horizontal backfill of cohesive soil on smooth vertical walls under active earth pressure condition, a height or depth of vertical section less than critical depth:-
A)
the backfill soil will be very unstable
B)
the state of stress in the backfill is maximum and critical
C)
is the depth upto which lateral support may be provided
D)
is the depth upto which the backfill can stand without lateral support
For cohesive soil under active earth pressure, the critical depth is the maximum vertical cut height that can stand unsupported due to cohesion. If the height/depth of the vertical section is less than this critical depth, the soil can remain stable without any lateral support. Hence option (d) is correct.
Why others are incorrect:
- (a) Incorrect: a depth less than critical depth does not make the soil very unstable; it is actually stable enough to stand unsupported.
- (b) Incorrect: the state of stress is not described as maximum and critical for this condition; the key idea is stability without support.
- (c) Incorrect: lateral support is generally needed when the depth exceeds the critical depth, not for depths less than it.
Among the various methods of controlling of crack in RCC water tank is/are:-
A)
the cement concrete mix should have the largest practical coarse aggregate as this will reduce the cement content
B)
Slowly filling up the Tank the first time
C)
Both (a) and (b) are correct
D)
Both (a) and (b) are incorrect
Crack control in RCC water tanks focuses on minimizing shrinkage, temperature, and restraint stresses. Using the largest practical coarse aggregate is generally a good concrete practice, but the statement given is not a specific crack-control measure for water tanks and the reason stated (“as this will reduce the cement content”) is not a reliable crack-control principle. Also, slowly filling the tank the first time is not a standard method of controlling cracking in the tank structure; it is more related to commissioning/initial testing and does not prevent cracking in the RCC itself. Therefore both (a) and (b) are incorrect, so option (d) is correct.
Why others are incorrect:
- (a) Incorrect: crack control in water tanks depends mainly on low shrinkage concrete, proper reinforcement, joints, curing, and temperature control; merely choosing the largest aggregate to reduce cement content is not a valid stated method.
- (b) Incorrect: slow initial filling does not control structural cracking; it may reduce sudden loading during testing, but it is not a crack-control method.
- (c) Incorrect because both statements are not correct.
Alteration of slope geometry for remedial measure taken in landslide control means:-
A)
complete removal of unstable material
B)
either remove some of the material near the top of unstable zone or to add material at the toe
C)
proper slope design by adoption of flatter uniform slope followed by proper surface drainage
D)
improving the soil slopes near vertical cuts by the inclusion of elements which are resistant to tensile, compressive, shear and/or bending forces
Alteration of slope geometry in landslide control means changing the slope profile to improve stability by reducing driving forces or increasing resisting forces. This is done either by removing material from the upper part of the unstable slope (reducing the load and driving moment) or by adding material at the toe (providing counterweight and increasing resistance). Hence, option (b) is correct.
Option (a) is incorrect because complete removal of unstable material is not the general meaning of slope-geometry alteration; it is only one possible remedial action in special cases. Option (c) is incorrect because adopting a flatter slope with drainage is a broader slope-stabilization measure, but the phrase specifically refers to modifying the geometry by cutting at the top or loading at the toe. Option (d) is incorrect because it describes soil reinforcement/retaining measures, not alteration of slope geometry.
According to classification of soil as per grain size (IS:1498-1970), silts and clays would be:-
A)
Less than 0.075mm
B)
0.075mm to 4.75mm
C)
0.075mm to 2.00mm
D)
0.475mm to 2.00mm
As per IS:1498-1970 (grain-size classification), soils finer than 0.075 mm are classified as silt and clay (fine-grained soils). Therefore, the correct range is less than 0.075 mm.
Why others are incorrect:
- b (0.075 mm to 4.75 mm): This includes sand and gravel-sized particles, not silts and clays.
- c (0.075 mm to 2.00 mm): This is only part of the sand range; it excludes finer silt/clay particles.
- d (0.475 mm to 2.00 mm): This is also within the sand range and not applicable to silts and clays.
The presence of organic impurities in sand can be detected if the solution of sodium hydroxide or caustic soda, when added to sand and stirred turns:-
A)
Brown
B)
Blue
C)
Red
D)
Green
Organic impurities in sand are detected by the color test with sodium hydroxide (caustic soda). When sand is shaken with NaOH solution, the presence of organic matter produces a brown coloration in the solution. Hence, the correct option is (a) Brown. The other colors are incorrect because this standard impurity test does not produce blue, red, or green coloration for organic impurities in sand.
A thin sheets or slices of wood of superior quality with the thickness varies from 0.40mm to 6mm or more, obtained by rotating a log of wood against a sharp knife of rotary cutter or saw are called:-
A)
Ply woods
B)
Fibre boards
C)
Compreg timber
D)
Veneers
The correct answer is **d) Veneers**. Veneers are very thin sheets or slices of high-quality wood, typically about **0.40 mm to 6 mm or more** thick, produced by **rotary cutting, slicing, or sawing** a log against a sharp knife or cutter. This matches the description exactly.
Why the others are incorrect:
- **a) Ply woods**: Plywood is made by bonding several thin layers of wood veneer together with adjacent layers having their grain directions at right angles. It is a finished product made from veneers, not the thin sheets themselves.
- **b) Fibre boards**: Fibre boards are manufactured boards made from wood fibres compressed and bonded together. They are not thin slices of wood from a log.
- **c) Compreg timber**: Compreg timber is a resin-impregnated, compressed wood product used for improved strength and durability. It is not the thin sheet material described in the question.
The chemical formula of ‘Gypsum’ is:-
A)
MgSO4 . 4H2O
B)
CaSO4 . 2H2O
C)
CaSO4 . 4H2O
D)
MgSO4 . 2H2O
Gypsum is calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. Therefore option b is correct. Option c (CaSO4·4H2O) is incorrect because gypsum contains 2 water molecules, not 4. Options a and d are incorrect because they are magnesium sulfate compounds (MgSO4), not calcium sulfate, so they do not represent gypsum.
Given the foundation on firm ground, the depth of Retaining wall / Breast wall below ground level or side drain or terrace level shall be at least:-
A)
300mm
B)
500mm
C)
600mm
D)
900mm
The minimum depth of a retaining wall/breast wall below ground level, side drain level, or terrace level on firm ground is generally taken as 500 mm to ensure adequate embedment, stability, and protection against undermining and erosion. Hence, option (b) 500 mm is correct.
Why the others are incorrect:
- (a) 300 mm: too shallow for a retaining/breast wall foundation on firm ground; it may not provide sufficient stability.
- (c) 600 mm: deeper than the usual minimum requirement, but not the standard minimum asked in the question.
- (d) 900 mm: unnecessarily deep for the stated condition and not the minimum prescribed depth.
The maximum thickness recommended to be maintained in a single operation for proper compaction while refilling the excavation of foundation is:-
A)
10cm
B)
15cm
C)
20cm
D)
30cm
For refilling foundation excavations, soil should be placed and compacted in thin layers so that compaction is effective throughout the full depth of each layer. The generally recommended maximum thickness for one layer is about 20 cm. This allows proper tamping/compaction and avoids loose pockets or uneven settlement.
Why the others are incorrect:
- 10 cm is thinner than necessary in normal foundation backfilling and is not the standard maximum recommended thickness.
- 15 cm is also acceptable in some cases, but the commonly cited maximum for proper compaction in foundation refilling is 20 cm.
- 30 cm is too thick for effective compaction in a single operation; the lower portion of the layer may remain inadequately compacted, leading to settlement.
The load which is held constant during Box shear test on a soil sample is:-
A)
Horizontal load
B)
Vertical load
C)
Both Horizontal and Vertical loads
D)
None of these
In a box shear test, the soil specimen is subjected to a constant normal (vertical) load while the horizontal load is increased until failure. The vertical load is kept constant so that the shear strength can be determined under a known normal stress. Option (a) is incorrect because the horizontal load is the one applied progressively to cause shear failure, not held constant. Option (c) is incorrect because both loads are not constant; only the vertical load is maintained constant. Option (d) is incorrect because the correct choice is clearly given by option (b).
Choose the Thermoplastic type of polymers from the followings:-
A)
Epoxies
B)
Polypropylene
C)
Polyesters
D)
Vinylester
Polypropylene is a thermoplastic polymer: it softens on heating and can be remoulded repeatedly without major chemical change. In contrast, epoxies and vinylesters are thermosetting polymers, meaning they cure into a rigid network and do not remelt on reheating. Polyesters, in the usual engineering-plastics context here, are generally treated as thermosetting resins when used with reinforcement (e.g., unsaturated polyester resins), so they are not the intended thermoplastic choice in this question.
‘Granite’ is an example of:-
A)
Plutonic rocks
B)
Hypobyssal rocks
C)
Volcanic rocks
D)
None of these
Granite is a plutonic (intrusive igneous) rock. It forms when magma cools slowly deep inside the Earth, allowing large crystals to develop. The other options are incorrect because volcanic rocks are extrusive igneous rocks formed at the surface, hypabyssal rocks form at shallow depths and are intermediate in texture, and ‘None of these’ is wrong since granite clearly belongs to the plutonic group.
The varnishes used for varnishing maps, pictures, covering wall papers etc are:-
A)
Spirit varnishes
B)
Oil varnishes
C)
Water varnishes
D)
Turpentine varnishes
Spirit varnishes are used for varnishing maps, pictures, and covering wall papers because they dry quickly, form a clear hard film, and are suitable for delicate indoor decorative work. Oil varnishes are slower-drying and are mainly used for durable exterior or heavy-duty finishes. Turpentine varnishes are not the standard choice for such fine decorative applications. Water varnishes are not used as true varnishes for this purpose, since varnishes generally require a resin dissolved in a suitable solvent to form a protective glossy film.
The intensity of loading at the base of the foundation which would cause shear failure of the soil support is:-
A)
Ultimate bearing capacity
B)
Safe bearing capacity
C)
Allowable bearing capacity
D)
None of these
The intensity of loading at the base of a foundation that causes shear failure of the supporting soil is the **ultimate bearing capacity**. It is the maximum pressure the soil can sustain before failure occurs.
Why others are incorrect:
- **Safe bearing capacity**: This is the allowable pressure after applying a factor of safety to the ultimate capacity; it is lower than the failure load.
- **Allowable bearing capacity**: This is the design pressure permitted considering both shear failure and settlement criteria, so it is not the failure-causing load.
- **None of these**: Incorrect because the correct term is clearly ultimate bearing capacity.
Moisture in timber, for any combination of vapour pressure and temperature, the corresponding moisture content such that there will be no inward or outward diffusion of water vapour, is called:-
A)
Average moisture content
B)
Equivalent moisture content
C)
Critical moisture content
D)
Equilibrium moisture content
The correct answer is **Equilibrium moisture content**. It is the moisture content of timber at which, for a given surrounding vapour pressure and temperature, there is **no net movement of moisture** into or out of the wood. In other words, the timber is in moisture balance with the surrounding air.
Why the others are incorrect:
- **Equivalent moisture content**: not the standard term for the no-diffusion condition in timber.
- **Average moisture content**: simply refers to the mean moisture present in the timber, not the balance condition with air.
- **Critical moisture content**: is the moisture level at which certain properties change significantly (often related to drying or strength behavior), but it does not mean no vapour diffusion.
Hence, the correct option is **d) Equilibrium moisture content**.
which one of the following formations has the highest specific yield for ground water harvesting:-
A)
Clay
B)
Sand
C)
Shale
D)
Gravel
Gravel has the highest specific yield because it consists of coarse, well-sorted particles with large pore spaces that drain readily under gravity, so it releases the maximum amount of stored groundwater. Sand also has good specific yield, but it is lower than gravel because its pores are smaller and retain more water by capillary forces. Clay has very low specific yield because its extremely fine particles hold water tightly and do not drain easily. Shale is a compact, low-permeability rock and generally yields very little groundwater.