Please keep at least one language enabled. || కనీసం ఒక భాషను ఎంచుకోండి.
Question 1
ప్రశ్న 1
A batch of burnt clay bricks is pale or yellowish, relatively soft, gives a dull sound when struck, and breaks easily during handling. Which diagnosis and engineering decision are most appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• The combination of pale colour, softness, dull sound and easy breakage is characteristic of inadequate burning rather than adequate vitrification.
• Under-firing leaves the clay body insufficiently matured, so strength, hardness and resistance to weathering can be poor.
• Such units are therefore unsuitable for quality permanent masonry merely because their external dimensions appear usable.
• Over-burnt bricks more commonly become excessively hard, dark, vitrified or distorted rather than soft and pale.
• Efflorescence is a soluble-salt phenomenon and does not explain the full set of symptoms described, so Option A is the sound engineering judgement.
• Under-firing leaves the clay body insufficiently matured, so strength, hardness and resistance to weathering can be poor.
• Such units are therefore unsuitable for quality permanent masonry merely because their external dimensions appear usable.
• Over-burnt bricks more commonly become excessively hard, dark, vitrified or distorted rather than soft and pale.
• Efflorescence is a soluble-salt phenomenon and does not explain the full set of symptoms described, so Option A is the sound engineering judgement.
వివరణ:
Question 2
ప్రశ్న 2
A kiln produces very hard, dark bricks that have become vitrified and noticeably distorted. What is the most appropriate assessment for ordinary regular masonry?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Excessive firing can cause partial vitrification, distortion and loss of the regular geometry required for good brick masonry.
• A very hard brick is not automatically a satisfactory masonry unit if its faces, edges and dimensions are badly distorted.
• Irregular units make it difficult to maintain uniform courses and mortar joints and can impair workmanship.
• Traditional specifications sometimes permit suitably dense over-burnt brick material to be broken for uses such as ballast or soling, but such reuse depends on the project specification and should not be assumed universally.
• Therefore Option B correctly separates possible material reuse from suitability for regular masonry.
• A very hard brick is not automatically a satisfactory masonry unit if its faces, edges and dimensions are badly distorted.
• Irregular units make it difficult to maintain uniform courses and mortar joints and can impair workmanship.
• Traditional specifications sometimes permit suitably dense over-burnt brick material to be broken for uses such as ballast or soling, but such reuse depends on the project specification and should not be assumed universally.
• Therefore Option B correctly separates possible material reuse from suitability for regular masonry.
వివరణ:
Question 3
ప్రశ్న 3
Why are visible nodules of free lime regarded as an undesirable defect in burnt clay bricks?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Free lime can remain as localized nodules within a fired brick when calcareous material is not properly processed or combined during manufacture.
• On later exposure to moisture, free calcium oxide can hydrate to calcium hydroxide and undergo a substantial increase in volume.
• Local expansion can generate internal stresses and lead to popping, cracking or spalling around the inclusion.
• This is why current general-quality requirements for common burnt clay bricks require freedom from nodules of free lime.
• The presence of such nodules does not prove high strength or remove soluble salts, so Option A is correct.
• On later exposure to moisture, free calcium oxide can hydrate to calcium hydroxide and undergo a substantial increase in volume.
• Local expansion can generate internal stresses and lead to popping, cracking or spalling around the inclusion.
• This is why current general-quality requirements for common burnt clay bricks require freedom from nodules of free lime.
• The presence of such nodules does not prove high strength or remove soluble salts, so Option A is correct.
వివరణ:
Question 4
ప్రశ్న 4
Which combination of conditions is fundamentally required for visible efflorescence to develop on brick masonry?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Efflorescence is produced when water-soluble salts migrate through or across masonry and crystallize at an exposed surface after evaporation.
• A soluble-salt source is therefore necessary, but the salts need not originate solely from the brick itself.
• Moisture must contact and dissolve the salts, and the resulting solution must be able to migrate through the masonry pore system or interfaces.
• Evaporation at or near the surface then leaves the characteristic deposit.
• Option A correctly identifies the interacting salt, moisture and transport conditions required for the phenomenon.
• A soluble-salt source is therefore necessary, but the salts need not originate solely from the brick itself.
• Moisture must contact and dissolve the salts, and the resulting solution must be able to migrate through the masonry pore system or interfaces.
• Evaporation at or near the surface then leaves the characteristic deposit.
• Option A correctly identifies the interacting salt, moisture and transport conditions required for the phenomenon.
వివరణ:
Question 5
ప్రశ్న 5
A newly constructed brick wall develops a white crystalline deposit. The site engineer immediately concludes that the bricks themselves must be the sole source of the salts. Which response is most technically defensible?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A white crystalline deposit on masonry is consistent with efflorescence, but its appearance alone does not identify the unique salt source.
• Soluble salts may be contributed by masonry units, mortar ingredients, backing materials, adjacent soil or other contacting materials.
• Moisture provides the transport mechanism that carries dissolved salts toward an evaporating surface.
• Effective diagnosis therefore requires investigation of both the salt source and the moisture path rather than automatically blaming the brick.
• Option B is consequently the most defensible engineering response.
• Soluble salts may be contributed by masonry units, mortar ingredients, backing materials, adjacent soil or other contacting materials.
• Moisture provides the transport mechanism that carries dissolved salts toward an evaporating surface.
• Effective diagnosis therefore requires investigation of both the salt source and the moisture path rather than automatically blaming the brick.
• Option B is consequently the most defensible engineering response.
వివరణ:
Question 6
ప్రశ్న 6
Repeated brushing removes efflorescence from an external brick wall, but the deposit returns after every period of rain. Which remedial principle should receive priority?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Recurring efflorescence indicates that the conditions supplying dissolved salts to the evaporation surface continue to exist.
• Brushing may remove a visible deposit, but it does not by itself stop water entry or salt transport through the wall.
• Durable control therefore begins by locating moisture sources such as rain penetration, rising damp or other wetting routes and correcting the relevant detailing or construction defect.
• The potential salt source should also be considered because both soluble salts and moisture are required for renewed deposition.
• Option B addresses the mechanism of recurrence rather than only its visible symptom.
• Brushing may remove a visible deposit, but it does not by itself stop water entry or salt transport through the wall.
• Durable control therefore begins by locating moisture sources such as rain penetration, rising damp or other wetting routes and correcting the relevant detailing or construction defect.
• The potential salt source should also be considered because both soluble salts and moisture are required for renewed deposition.
• Option B addresses the mechanism of recurrence rather than only its visible symptom.
వివరణ:
Question 7
ప్రశ్న 7
A Class 15 common burnt clay brick gives a 'moderate' efflorescence rating when tested by the prescribed method. What is the correct assessment under IS 1077:2025?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• IS 1077:2025 applies different efflorescence limits to lower and higher strength classes.
• Bricks up to and including Class 12.5 may have an efflorescence rating not more than moderate.
• Classes higher than 12.5, including Class 15, are required to have a rating not more than slight.
• A moderate result therefore exceeds the permitted efflorescence level for the specified Class 15 brick.
• Uniform colour or adequate strength does not cancel failure of an independent physical requirement, so Option B is correct.
• Bricks up to and including Class 12.5 may have an efflorescence rating not more than moderate.
• Classes higher than 12.5, including Class 15, are required to have a rating not more than slight.
• A moderate result therefore exceeds the permitted efflorescence level for the specified Class 15 brick.
• Uniform colour or adequate strength does not cancel failure of an independent physical requirement, so Option B is correct.
వివరణ:
Question 8
ప్రశ్న 8
A Class 10 common burnt clay brick has an efflorescence rating of 'moderate'. Which statement is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Class 10 lies within the group up to and including Class 12.5 under the current common-brick specification.
• For this group, the efflorescence rating is permitted to be not more than moderate.
• A moderate rating therefore satisfies this particular requirement at its limiting acceptable level.
• Passing the efflorescence requirement does not establish compressive strength, water absorption, dimensions, warpage or the other independent conformity requirements.
• Hence Option A gives the correct and properly limited interpretation.
• For this group, the efflorescence rating is permitted to be not more than moderate.
• A moderate rating therefore satisfies this particular requirement at its limiting acceptable level.
• Passing the efflorescence requirement does not establish compressive strength, water absorption, dimensions, warpage or the other independent conformity requirements.
• Hence Option A gives the correct and properly limited interpretation.
వివరణ:
Question 9
ప్రశ్న 9
A Class 20 common burnt clay brick has a dry mass of 2.60 kg and a mass of 2.98 kg after the prescribed 24-hour immersion. What is the correct conclusion based only on water absorption?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Water absorption is calculated as [(wet mass − dry mass) / dry mass] × 100.
• The mass gain is 2.98 − 2.60 = 0.38 kg.
• Therefore the absorption is (0.38 / 2.60) × 100 = approximately 14.6 percent.
• Class 20 is above Class 12.5, so IS 1077:2025 limits its 24-hour water absorption to not more than 15 percent by dry mass.
• The stated result therefore satisfies this particular requirement, making Option B correct, although full conformity requires the remaining properties to be checked.
• The mass gain is 2.98 − 2.60 = 0.38 kg.
• Therefore the absorption is (0.38 / 2.60) × 100 = approximately 14.6 percent.
• Class 20 is above Class 12.5, so IS 1077:2025 limits its 24-hour water absorption to not more than 15 percent by dry mass.
• The stated result therefore satisfies this particular requirement, making Option B correct, although full conformity requires the remaining properties to be checked.
వివరణ:
Question 10
ప్రశ్న 10
A common burnt clay brick lot has an average 24-hour water absorption of 18 percent. How should this result be interpreted under IS 1077:2025 if the same numerical result is considered against Class 10 and Class 15 requirements?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• IS 1077:2025 sets the maximum 24-hour water absorption at 20 percent by dry mass for classes up to and including Class 12.5.
• A value of 18 percent is therefore within the absorption limit applicable to Class 10.
• For classes higher than 12.5, including Class 15, the maximum permitted absorption is 15 percent.
• The same 18 percent result consequently exceeds the Class 15 absorption limit even though it would meet the Class 10 absorption criterion.
• Option A correctly demonstrates that a test result must be interpreted against the requirement of the specified class rather than in isolation.
• A value of 18 percent is therefore within the absorption limit applicable to Class 10.
• For classes higher than 12.5, including Class 15, the maximum permitted absorption is 15 percent.
• The same 18 percent result consequently exceeds the Class 15 absorption limit even though it would meet the Class 10 absorption criterion.
• Option A correctly demonstrates that a test result must be interpreted against the requirement of the specified class rather than in isolation.
వివరణ:
Question 11
ప్రశ్న 11
A sample of 70 mm high common burnt clay bricks has an average warpage of 3.2 mm. What is the correct assessment under IS 1077:2025?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• IS 1077:2025 limits average warpage to 3 mm or 5 percent of the brick height, whichever is lower.
• Five percent of a 70 mm height is 3.5 mm.
• Comparing 3 mm and 3.5 mm shows that the governing limit is 3 mm.
• The measured average warpage of 3.2 mm exceeds that limit and therefore does not comply.
• Option B correctly applies the 'whichever is lower' condition rather than using the percentage limit alone.
• Five percent of a 70 mm height is 3.5 mm.
• Comparing 3 mm and 3.5 mm shows that the governing limit is 3 mm.
• The measured average warpage of 3.2 mm exceeds that limit and therefore does not comply.
• Option B correctly applies the 'whichever is lower' condition rather than using the percentage limit alone.
వివరణ:
Question 12
ప్రశ్న 12
A sample of 40 mm high common burnt clay bricks has an average warpage of 1.9 mm. Which conclusion is correct under IS 1077:2025?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• The standard requires average warpage not to exceed 3 mm or 5 percent of brick height, whichever is lower.
• Five percent of 40 mm is 2.0 mm.
• Since 2.0 mm is lower than the absolute 3 mm value, the governing limit for this thin brick is 2.0 mm.
• The measured average warpage of 1.9 mm is below that limit and therefore complies with this requirement.
• Hence Option B is correct.
• Five percent of 40 mm is 2.0 mm.
• Since 2.0 mm is lower than the absolute 3 mm value, the governing limit for this thin brick is 2.0 mm.
• The measured average warpage of 1.9 mm is below that limit and therefore complies with this requirement.
• Hence Option B is correct.
వివరణ:
Question 13
ప్రశ్న 13
A common burnt clay brick sample gives an average initial rate of absorption of 44 N/m²/min. Which statement is correct under IS 1077:2025?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Initial rate of absorption measures the rate at which a relatively dry brick initially takes up water through its contact surface.
• IS 1077:2025 requires the average IRA value for common burnt clay bricks to be less than 40 N/m²/min.
• A measured average of 44 N/m²/min is above that requirement and therefore fails it.
• The 24-hour total water-absorption test is a separate property and cannot automatically override a non-compliant IRA result.
• Excessively high initial suction can also affect mortar-brick interface behaviour during construction, so Option B is correct.
• IS 1077:2025 requires the average IRA value for common burnt clay bricks to be less than 40 N/m²/min.
• A measured average of 44 N/m²/min is above that requirement and therefore fails it.
• The 24-hour total water-absorption test is a separate property and cannot automatically override a non-compliant IRA result.
• Excessively high initial suction can also affect mortar-brick interface behaviour during construction, so Option B is correct.
వివరణ:
Question 14
ప్రశ్న 14
A Class 35 brick lot has an average compressive strength of 36.2 N/mm², but the lowest individual result is 29.5 N/mm². What is the correct strength-related conclusion under IS 1077:2025?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• The average result of 36.2 N/mm² exceeds the 35 N/mm² minimum average strength required for Class 35.
• However, an individual tested brick may not fall more than 15 percent below the corresponding class strength.
• Eighty-five percent of 35 N/mm² is 29.75 N/mm².
• The lowest individual value of 29.5 N/mm² is below 29.75 N/mm² and therefore does not satisfy the Class 35 individual-strength requirement.
• Hence Option B is correct even though the lot average itself is adequate.
• However, an individual tested brick may not fall more than 15 percent below the corresponding class strength.
• Eighty-five percent of 35 N/mm² is 29.75 N/mm².
• The lowest individual value of 29.5 N/mm² is below 29.75 N/mm² and therefore does not satisfy the Class 35 individual-strength requirement.
• Hence Option B is correct even though the lot average itself is adequate.
వివరణ:
Question 15
ప్రశ్న 15
Four candidate lots are offered for exposed external brickwork specified as Class 15 common burnt clay bricks. Considering only the properties stated below, which lot shows no non-conformity with the corresponding IS 1077:2025 limits?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Class 15 bricks require an average compressive strength of at least 15 N/mm², and all four stated lots satisfy that average-strength figure.
• Because Class 15 is above Class 12.5, the water-absorption limit is 15 percent and the efflorescence rating must be not more than slight.
• For a 70 mm high brick, the warpage limit is the lower of 3 mm and 3.5 mm, so 3 mm governs.
• Lot B fails on moderate efflorescence, Lot C fails on 15.8 percent absorption, and Lot D fails on 3.4 mm warpage.
• Lot A has no failure among the stated properties, although other applicable requirements would still have to be verified before full conformity could be declared.
• Because Class 15 is above Class 12.5, the water-absorption limit is 15 percent and the efflorescence rating must be not more than slight.
• For a 70 mm high brick, the warpage limit is the lower of 3 mm and 3.5 mm, so 3 mm governs.
• Lot B fails on moderate efflorescence, Lot C fails on 15.8 percent absorption, and Lot D fails on 3.4 mm warpage.
• Lot A has no failure among the stated properties, although other applicable requirements would still have to be verified before full conformity could be declared.
వివరణ:
Question 16
ప్రశ్న 16
Why can severe dimensional irregularity be treated as a durability and serviceability concern rather than merely an aesthetic defect?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Dimensional quality affects how masonry units fit together and how uniformly mortar joints can be formed.
• Severely irregular or warped bricks can lead to variable joint thickness, poor alignment and difficulty maintaining true courses.
• Non-uniform workmanship can in turn create localized weaknesses, easier paths for moisture penetration and poor surface performance even when the individual brick material is strong.
• Dimensional accuracy therefore has practical consequences beyond appearance alone.
• Option A correctly connects geometric quality with masonry performance without claiming that irregularity automatically changes the intrinsic brick strength.
• Severely irregular or warped bricks can lead to variable joint thickness, poor alignment and difficulty maintaining true courses.
• Non-uniform workmanship can in turn create localized weaknesses, easier paths for moisture penetration and poor surface performance even when the individual brick material is strong.
• Dimensional accuracy therefore has practical consequences beyond appearance alone.
• Option A correctly connects geometric quality with masonry performance without claiming that irregularity automatically changes the intrinsic brick strength.
వివరణ:
Question 17
ప్రశ్న 17
A site supervisor accepts a lot solely because the bricks give a clear ringing sound when struck together and resist scratching by a fingernail. Which criticism is most appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A clear ringing sound and resistance to simple scratching are traditional field indicators of general soundness and surface hardness.
• They are qualitative observations rather than standardized measurements of a brick's compressive strength or moisture-related properties.
• Formal conformity requires the relevant product and test requirements to be satisfied using prescribed procedures.
• A brick can appear hard and sound yet still fail water absorption, efflorescence, dimensional, warpage or strength criteria.
• Therefore Option B correctly treats field checks as screening aids rather than substitutes for specification compliance.
• They are qualitative observations rather than standardized measurements of a brick's compressive strength or moisture-related properties.
• Formal conformity requires the relevant product and test requirements to be satisfied using prescribed procedures.
• A brick can appear hard and sound yet still fail water absorption, efflorescence, dimensional, warpage or strength criteria.
• Therefore Option B correctly treats field checks as screening aids rather than substitutes for specification compliance.
వివరణ:
Question 18
ప్రశ్న 18
Current general-quality requirements for common burnt clay building bricks specifically call for bricks to be free from which combination?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• IS 1077:2025 requires common burnt clay building bricks to be free from cracks and flaws and from nodules of free lime.
• Cracks and flaws can indicate poor manufacture or damage and may adversely affect handling, appearance or mechanical performance.
• Free-lime nodules are undesirable because later hydration can produce expansive local damage such as popping or cracking.
• The requirement does not mean that every microscopic pore or every harmless natural surface variation must be absent.
• Therefore Option A accurately identifies the defects explicitly excluded by the general-quality provisions.
• Cracks and flaws can indicate poor manufacture or damage and may adversely affect handling, appearance or mechanical performance.
• Free-lime nodules are undesirable because later hydration can produce expansive local damage such as popping or cracking.
• The requirement does not mean that every microscopic pore or every harmless natural surface variation must be absent.
• Therefore Option A accurately identifies the defects explicitly excluded by the general-quality provisions.
వివరణ:
Question 19
ప్రశ్న 19
Match the observed brick condition with the most appropriate underlying quality issue:
1. Whitish crystalline deposit after wetting and drying
2. Local popping around a calcareous inclusion
3. Soft pale brick that breaks easily
4. Hard dark brick with badly distorted shape
P. Excessive firing/over-burning
Q. Soluble-salt migration and evaporation
R. Free-lime nodule hydration
S. Insufficient firing/under-burning
1. Whitish crystalline deposit after wetting and drying
2. Local popping around a calcareous inclusion
3. Soft pale brick that breaks easily
4. Hard dark brick with badly distorted shape
P. Excessive firing/over-burning
Q. Soluble-salt migration and evaporation
R. Free-lime nodule hydration
S. Insufficient firing/under-burning
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• A whitish crystalline surface deposit formed after wetting and drying is characteristic of efflorescence, so 1-Q is correct.
• Local popping associated with a calcareous inclusion is consistent with expansion caused by hydration of a free-lime nodule, giving 2-R.
• A soft pale brick that breaks easily is a typical indication of insufficient firing, so 3-S is appropriate.
• Excessive firing can produce a very hard, dark, vitrified and distorted brick, giving 4-P.
• Hence the complete matching is 1-Q, 2-R, 3-S and 4-P, which corresponds to Option A.
• Local popping associated with a calcareous inclusion is consistent with expansion caused by hydration of a free-lime nodule, giving 2-R.
• A soft pale brick that breaks easily is a typical indication of insufficient firing, so 3-S is appropriate.
• Excessive firing can produce a very hard, dark, vitrified and distorted brick, giving 4-P.
• Hence the complete matching is 1-Q, 2-R, 3-S and 4-P, which corresponds to Option A.
వివరణ:
Question 20
ప్రశ్న 20
For a masonry wall that is likely to experience frequent rain exposure, which selection strategy is most defensible?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Rain-exposed masonry performance depends on the brick units, mortar joints, workmanship and detailing acting together rather than on compressive strength alone.
• Bricks should satisfy the applicable strength, water-absorption, efflorescence, dimensional and other specified requirements for the intended product.
• Lower uncontrolled moisture uptake and proper jointing help reduce water ingress, while sound detailing such as copings, flashings and drainage paths controls exposure at the wall-system level.
• A high-strength but excessively absorptive, cracked or poorly dimensioned brick is not automatically a durable choice.
• Therefore Option B expresses the balanced engineering approach to material selection for rain exposure.
• Bricks should satisfy the applicable strength, water-absorption, efflorescence, dimensional and other specified requirements for the intended product.
• Lower uncontrolled moisture uptake and proper jointing help reduce water ingress, while sound detailing such as copings, flashings and drainage paths controls exposure at the wall-system level.
• A high-strength but excessively absorptive, cracked or poorly dimensioned brick is not automatically a durable choice.
• Therefore Option B expresses the balanced engineering approach to material selection for rain exposure.
వివరణ:
Question 21
ప్రశ్న 21
During storage, pallets of bricks intended for facing masonry are left directly on wet soil and uncovered during repeated rain. Which durability concern is most relevant?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Efflorescence requires soluble salts and moisture transport, and poor storage can provide both additional moisture and contamination from the ground.
• Bricks stored directly on wet soil can be exposed to dissolved salts that may later migrate to visible masonry surfaces.
• Repeated rain also leaves the units wetter at the time of construction and can complicate moisture control and appearance.
• Good practice therefore keeps masonry materials off the ground and protects them from unnecessary precipitation and contamination.
• Option A correctly identifies the durability and appearance concern associated with the described storage condition.
• Bricks stored directly on wet soil can be exposed to dissolved salts that may later migrate to visible masonry surfaces.
• Repeated rain also leaves the units wetter at the time of construction and can complicate moisture control and appearance.
• Good practice therefore keeps masonry materials off the ground and protects them from unnecessary precipitation and contamination.
• Option A correctly identifies the durability and appearance concern associated with the described storage condition.
వివరణ:
Question 22
ప్రశ్న 22
Which statement best distinguishes under-burning from over-burning as brick-quality defects?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Firing must mature the clay sufficiently to develop the desired strength, hardness and durability without causing destructive distortion.
• Under-burning leaves the ceramic body insufficiently developed and commonly produces weaker, softer and less durable bricks.
• Over-burning can drive the material toward excessive vitrification, resulting in very hard, dark and distorted units that may be unsuitable for accurate regular masonry.
• The two defects therefore arise on opposite sides of the proper firing range and can affect much more than colour alone.
• Option A correctly states the engineering distinction.
• Under-burning leaves the ceramic body insufficiently developed and commonly produces weaker, softer and less durable bricks.
• Over-burning can drive the material toward excessive vitrification, resulting in very hard, dark and distorted units that may be unsuitable for accurate regular masonry.
• The two defects therefore arise on opposite sides of the proper firing range and can affect much more than colour alone.
• Option A correctly states the engineering distinction.
వివరణ:
Question 23
ప్రశ్న 23
Consider the following statements about durability-related assessment of burnt clay bricks:
1. Passing the compressive-strength requirement alone does not establish complete conformity.
2. Excessive water absorption can be a durability concern even when strength is adequate.
3. Efflorescence should be interpreted in relation to soluble salts and moisture movement.
4. Severe warpage may impair masonry workmanship even if the brick material itself is strong.
Which statements are correct?
1. Passing the compressive-strength requirement alone does not establish complete conformity.
2. Excessive water absorption can be a durability concern even when strength is adequate.
3. Efflorescence should be interpreted in relation to soluble salts and moisture movement.
4. Severe warpage may impair masonry workmanship even if the brick material itself is strong.
Which statements are correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• Statement 1 is correct because brick conformity includes several independent physical and dimensional requirements in addition to compressive strength.
• Statement 2 is correct because excessive absorption indicates undesirable moisture uptake and may affect durability and masonry behaviour.
• Statement 3 is correct because efflorescence results from the transport and subsequent crystallization of soluble salts by moisture.
• Statement 4 is correct because excessive warpage can cause irregular joints, alignment problems and poor workmanship despite adequate material strength.
• All four statements are therefore correct, making Option D the unique answer.
• Statement 2 is correct because excessive absorption indicates undesirable moisture uptake and may affect durability and masonry behaviour.
• Statement 3 is correct because efflorescence results from the transport and subsequent crystallization of soluble salts by moisture.
• Statement 4 is correct because excessive warpage can cause irregular joints, alignment problems and poor workmanship despite adequate material strength.
• All four statements are therefore correct, making Option D the unique answer.
వివరణ:
Question 24
ప్రశ్న 24
An exposed brick wall shows heavy salt deposits together with powdering and flaking of the brick surface in the standardized efflorescence assessment. Which rating and interpretation are appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• The standardized efflorescence assessment considers both the extent of salt deposition and whether the exposed surface undergoes deterioration.
• A heavy deposit without powdering or flaking can fall within the Heavy category under the test method.
• When a heavy salt deposit is accompanied by powdering or flaking of the exposed surface, the classification becomes Serious.
• IS 1077:2025 permits no more than moderate efflorescence up to Class 12.5 and no more than slight for higher classes, so Serious is beyond the permitted level for every common-brick class.
• Therefore Option D gives both the correct rating and the correct conformity implication.
• A heavy deposit without powdering or flaking can fall within the Heavy category under the test method.
• When a heavy salt deposit is accompanied by powdering or flaking of the exposed surface, the classification becomes Serious.
• IS 1077:2025 permits no more than moderate efflorescence up to Class 12.5 and no more than slight for higher classes, so Serious is beyond the permitted level for every common-brick class.
• Therefore Option D gives both the correct rating and the correct conformity implication.
వివరణ:
Question 25
ప్రశ్న 25
A Class 20 common burnt clay brick lot has the following results: average compressive strength 20.4 N/mm²; lowest individual strength 17.1 N/mm²; 24-hour water absorption 14.8%; efflorescence slight; average warpage 2.9 mm for 90 mm high bricks; average initial rate of absorption 39 N/m²/min; and average modulus-of-rupture/compressive-strength ratio 0.072. Based only on these stated requirements of IS 1077:2025, what is the correct conclusion?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
• The average compressive strength of 20.4 N/mm² exceeds the Class 20 minimum, and the individual lower limit is 20 × 0.85 = 17.0 N/mm², so 17.1 N/mm² satisfies the stated strength criteria.
• For a class above 12.5, the maximum 24-hour water absorption is 15 percent, so 14.8 percent complies, and slight efflorescence is also within the permitted rating.
• For a 90 mm high brick, the warpage limit is the lower of 3 mm and 4.5 mm, so the measured 2.9 mm complies.
• The IRA of 39 N/m²/min is below 40 N/m²/min, and the modulus-of-rupture/compressive-strength ratio of 0.072 is greater than 0.07.
• Hence all of the specifically stated requirements are satisfied, but full conformity still requires proper sampling, valid test procedures and compliance with the remaining applicable provisions, making Option C correct.
• For a class above 12.5, the maximum 24-hour water absorption is 15 percent, so 14.8 percent complies, and slight efflorescence is also within the permitted rating.
• For a 90 mm high brick, the warpage limit is the lower of 3 mm and 4.5 mm, so the measured 2.9 mm complies.
• The IRA of 39 N/m²/min is below 40 N/m²/min, and the modulus-of-rupture/compressive-strength ratio of 0.072 is greater than 0.07.
• Hence all of the specifically stated requirements are satisfied, but full conformity still requires proper sampling, valid test procedures and compliance with the remaining applicable provisions, making Option C correct.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: A. Likely under-burnt bricks; reject them for quality permanent masonry because inadequate firing has left them weak and less durable. సమాధానం: A.
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Question 2 ప్రశ్న 2Answer: B. Reject them for regular masonry where dimensional accuracy and proper bonding are required; any alternative reuse should be permitted only where a suitable specification allows it. సమాధానం: B.
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Question 3 ప్రశ్న 3Answer: A. They can hydrate and expand after construction, creating local stresses that may cause cracking, popping or spalling. సమాధానం: A.
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Question 4 ప్రశ్న 4Answer: A. A source of soluble salts, moisture capable of dissolving and transporting them, and a path to a surface where evaporation can leave the salts behind సమాధానం: A.
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Question 5 ప్రశ్న 5Answer: B. The conclusion is premature because salts may originate from bricks, mortar, backing materials, soil or other materials in contact with the masonry, and moisture transport must also be investigated. సమాధానం: B.
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Question 6 ప్రశ్న 6Answer: B. Identify and reduce the recurring moisture path and relevant salt source instead of treating repeated surface removal as the complete solution. సమాధానం: B.
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Question 7 ప్రశ్న 7Answer: B. It fails the efflorescence requirement because classes higher than 12.5 are limited to not more than slight efflorescence. సమాధానం: B.
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Question 8 ప్రశ్న 8Answer: A. It satisfies the efflorescence criterion for its class, although other specification requirements must still be checked. సమాధానం: A.
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Question 9 ప్రశ్న 9Answer: B. Water absorption is about 14.6%, so it satisfies the 15% limit applicable to this class. సమాధానం: B.
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Question 10 ప్రశ్న 10Answer: A. It satisfies the absorption criterion for Class 10 but not for Class 15. సమాధానం: A.
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Question 11 ప్రశ్న 11Answer: B. It fails because the limit is the lower of 3 mm and 5% of the brick height, which is 3 mm in this case. సమాధానం: B.
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Question 12 ప్రశ్న 12Answer: B. It complies because the governing limit is 2.0 mm. సమాధానం: B.
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Question 13 ప్రశ్న 13Answer: B. It fails the IRA requirement because the average value is required to be less than 40 N/m²/min. సమాధానం: B.
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Question 14 ప్రశ్న 14Answer: B. It fails the Class 35 individual-strength requirement because 29.5 N/mm² is below 85% of 35 N/mm². సమాధానం: B.
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Question 15 ప్రశ్న 15Answer: A. Average strength 15.8 N/mm²; water absorption 14.2%; efflorescence slight; average warpage 2.4 mm for 70 mm high bricks సమాధానం: A.
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Question 16 ప్రశ్న 16Answer: A. It can force irregular mortar joints, impair alignment and workmanship, and create non-uniform local conditions in masonry. సమాధానం: A.
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Question 17 ప్రశ్న 17Answer: B. The observations are useful preliminary indicators of soundness and hardness, but they cannot establish compliance with strength, absorption, efflorescence, warpage and other specified requirements. సమాధానం: B.
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Question 18 ప్రశ్న 18Answer: A. Cracks, flaws and nodules of free lime సమాధానం: A.
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Question 19 ప్రశ్న 19Answer: A. 1-Q, 2-R, 3-S, 4-P సమాధానం: A.
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Question 20 ప్రశ్న 20Answer: B. Select bricks that meet the required strength class and moisture-related limits, use compatible mortar and detailing, and control rain penetration rather than relying on brick strength alone. సమాధానం: B.
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Question 21 ప్రశ్న 21Answer: A. Ground and rainwater can introduce moisture and soluble salts, increasing staining or efflorescence risk before and after construction. సమాధానం: A.
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Question 22 ప్రశ్న 22Answer: A. Under-burning tends to leave bricks weak and insufficiently matured, whereas over-burning can cause excessive vitrification, darkening and distortion. సమాధానం: A.
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Question 23 ప్రశ్న 23Answer: D. 1, 2, 3 and 4 సమాధానం: D.
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Question 24 ప్రశ్న 24Answer: D. Serious; the deposit is accompanied by powdering or flaking and is unacceptable for common burnt clay brick classes. సమాధానం: D.
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Question 25 ప్రశ్న 25Answer: C. The stated results satisfy all of the listed requirements, although complete conformity still depends on the remaining applicable requirements and valid sampling/testing. సమాధానం: C.