Test 30 - Cement Mortar Properties, Proportions and Applications

Question 1 ప్రశ్న 1

Which statement correctly describes the Indian Standard framework relevant to ordinary cement mortar used in masonry and plastering work?

A IS 2250 deals with preparation and use of masonry mortars, IS 2116 specifies sand for masonry mortar, and IS 1542 specifies sand for plaster. B IS 2250 is exclusively a cement-strength specification and does not deal with masonry mortar. C IS 2116 specifies coarse aggregate for reinforced concrete, while IS 1542 specifies structural steel. D All mortar materials and applications are governed solely by IS 383.

Question 2 ప్రశ్న 2

What are the basic constituents of a plain cement-sand mortar?

A Cement, suitable sand and water B Cement, coarse aggregate and reinforcing steel C Sand, bitumen and lime only D Cement and coarse aggregate without water

Question 3 ప్రశ్న 3

What is an important function of properly graded sand in cement mortar?

A It provides bulk and a suitable particle skeleton while helping control shrinkage and cement-paste demand. B It chemically replaces all the cement required for strength. C It prevents cement hydration. D It is used only to change the colour of mortar.

Question 4 ప్రశ్న 4

According to IS 2250, how should the quantity of water for masonry mortar generally be selected?

A Use only enough water to obtain the required working consistency and avoid excess water. B Use a fixed water-cement ratio of exactly 1.00 for every mortar. C Add water until segregation becomes visible. D The quantity of water is unrelated to the masonry unit or required consistency.

Question 5 ప్రశ్న 5

Which statement best distinguishes workability from cohesiveness of fresh cement mortar?

A Workability concerns ease of spreading and handling, while cohesiveness concerns the mortar's ability to remain homogeneous without segregation. B Workability and cohesiveness are exactly the same as 28-day compressive strength. C Cohesiveness refers only to cement colour. D Workability is measured solely by the cement grade number.

Question 6 ప్రశ్న 6

Why is good water retentivity particularly important when mortar is used with masonry units having high suction?

A It prevents the masonry unit from removing water from the mortar so rapidly that workability and hydration are adversely affected. B It ensures that all water evaporates immediately after laying. C It eliminates the need for cement in the mortar. D It makes the masonry unit completely non-absorbent.

Question 7 ప్రశ్న 7

Under the IS 2250 water-retentivity test concept, what minimum relationship is specified for mortar used where water retentivity needs to be assessed?

A Flow after suction should not be less than 70 percent of the flow before suction. B Flow after suction must be exactly twice the initial flow. C Flow after suction must be zero. D Water retentivity is determined only from compressive strength.

Question 8 ప్రశ్న 8

Which matching of recommended mortar-consistency penetration with application is correct under IS 2250?

A Solid bricks: 90–130 mm; perforated bricks: 70–80 mm; cavity filling: 130–150 mm B Solid bricks: 10–20 mm; perforated bricks: 130–150 mm; cavity filling: 20–30 mm C Solid bricks: 130–150 mm; perforated bricks: 130–150 mm; cavity filling: 70–80 mm D Exactly 100 mm penetration is mandatory for every masonry application.

Question 9 ప్రశ్న 9

Which statement correctly describes how masonry mortar should preferably be specified under IS 2250?

A By mortar grade based on minimum 28-day compressive strength, with nominal mix proportions provided as guidance. B Only by the colour of the cement used. C Only by water content, with strength ignored. D Every masonry application must use the same 1:3 mortar.

Question 10 ప్రశ్న 10

Which pair correctly matches masonry-mortar grade with its 28-day compressive-strength range under IS 2250?

A MM 3: 3–5 N/mm²; MM 5: 5–7.5 N/mm² B MM 3: 0.3–0.5 N/mm²; MM 5: exactly 50 N/mm² C MM 3: 7.5 N/mm² and above; MM 5: 0.5–0.7 N/mm² D Both MM 3 and MM 5 necessarily have the same strength

Question 11 ప్రశ్న 11

Which set correctly matches plain cement-sand nominal proportions, by loose volume, with the corresponding IS 2250 mortar grades?

A 1:6 – MM 3; 1:5 – MM 5; 1:4 or 1:3 – MM 7.5 B 1:6 – MM 7.5; 1:5 – MM 0.5; 1:3 – MM 0.7 C 1:8 – MM 7.5; 1:3 – MM 0.5 D Mortar grades have no relationship at all with mix proportions

Question 12 ప్రశ్న 12

Compared with a 1:6 cement-sand mortar, what does a 1:3 cement-sand mortar represent when both proportions are measured consistently by volume?

A A richer mortar containing more cement relative to sand B A leaner mortar containing less cement relative to sand C A mortar containing no fine aggregate D A mortar having exactly the same cement content

Question 13 ప్రశ్న 13

Ignoring volume change on mixing, what fraction of the combined loose dry constituent volume is cement in a 1:6 cement-sand mortar?

A 1/7 B 1/6 C 1/5 D 6/7

Question 14 ప్రశ్న 14

A batch is to contain 0.84 m³ of combined loose cement and sand measured in a 1:6 proportion, ignoring subsequent volume change. What loose volumes of cement and sand are required?

A 0.12 m³ cement and 0.72 m³ sand B 0.14 m³ cement and 0.70 m³ sand C 0.21 m³ cement and 0.63 m³ sand D 0.42 m³ cement and 0.42 m³ sand

Question 15 ప్రశ్న 15

An external masonry wall is frequently exposed to rain but will receive protective plaster or rendering. Which statement best reflects IS 2250 mortar-selection guidance?

A The mortar should not be below MM 0.7 and MM 2 is preferred. B Only MM 0.5 is permitted. C Mortar strength is irrelevant when protective plaster is provided. D Only neat cement without sand may be used.

Question 16 ప్రశ్న 16

An external masonry wall will be frequently exposed to rain and will have no protective plaster, rendering or other finish. What minimum mortar grade is specified by IS 2250 for this condition?

A MM 0.5 B MM 0.7 C MM 2 D MM 7.5 only

Question 17 ప్రశ్న 17

For a load-bearing internal masonry wall, which IS 2250 recommendation is most accurate?

A MM 0.7 or higher is preferred for high durability, but the grade should in no case be below MM 0.5. B Only MM 7.5 may be used. C The mortar must always be 1:3 irrespective of the loading. D Internal load-bearing masonry requires no mortar-strength consideration.

Question 18 ప్రశ్న 18

Masonry in a foundation below the damp-proof course is located in soil saturated with water. Which selection best reflects IS 2250?

A MM 3 should be used, and in no case should the grade be below MM 2. B MM 0.5 is mandatory because wet soil requires a weak mortar. C Only lime putty without sand may be used. D Exposure to saturated soil does not influence mortar selection.

Question 19 ప్రశ్న 19

Which application requires a masonry mortar grade of at least MM 3 according to IS 2250?

A Masonry in a building subjected to machinery vibration B Every non-load-bearing internal partition regardless of conditions C Temporary dry stacking without mortar D Painting of plastered surfaces

Question 20 ప్రశ్న 20

For bedding joints in masonry constructed with large concrete blocks, what minimum mortar grade does IS 2250 specify?

A MM 0.5 B MM 0.7 C MM 3 D No mortar is required

Question 21 ప్రశ్న 21

Which sequence correctly describes preparation of ordinary cement-sand mortar under IS 2250?

A Measure the materials, dry-mix cement and sand to uniform colour, then add the required water and mix to workable consistency. B Add all water to the sand first, allow it to segregate, and finally sprinkle dry cement on top. C Mix cement with coarse aggregate only and omit sand. D Add excess water first because the final consistency is independent of water content.

Question 22 ప్రశ్న 22

When cement mortar is prepared in a mechanical mixer under IS 2250, what minimum mixing duration is specified after addition of water?

A At least 30 seconds B At least 1 minute C At least 3 minutes D Exactly 30 minutes

Question 23 ప్రశ్న 23

Which statement correctly reflects IS 2250 practice regarding the quantity and retempering of ordinary cement mortar?

A Generally only enough cement mortar for about 30 minutes of work should be mixed, and mortar stiffened by evaporation may be retempered with water only within 60 minutes from addition of cement. B An entire day's cement mortar should always be mixed at once and freely retempered at any age. C Retempering is mandatory after final setting. D Cement mortar may be stored indefinitely if extra water is added periodically.

Question 24 ప్రశ్న 24

Why is simply adding excessive water an unsuitable way of improving the workability of cement mortar?

A Excess water can promote segregation, increase shrinkage and porosity, and reduce hardened strength and durability. B Excess water always increases mortar strength. C Water has no effect on fresh or hardened mortar. D Excess water converts sand into coarse aggregate.

Question 25 ప్రశ్న 25

Which statement about the selection of a mortar proportion for masonry, plastering and pointing is most technically appropriate?

A The required proportion should follow the specified application, exposure and performance requirement; common practice may use richer mixes such as 1:3 for pointing or demanding finishes and leaner mixes such as 1:6 for suitable general masonry, but these are not universal substitutions for the project specification. B Cement mortar 1:3 is mandatory for every masonry, plastering and pointing operation. C Cement mortar 1:8 is always stronger than 1:3 because it contains more sand. D Mortar proportions may be selected without considering surface, exposure, masonry unit or required strength.

Question 26 ప్రశ్న 26

A specification calls for flush pointing of brickwork in cement mortar 1:3. Compared with mortar 1:6, why is the 1:3 mix described as richer?

A It contains twice as much cement relative to the same quantity of sand ratio basis and therefore has a higher binder-to-sand proportion. B It contains no cement. C It contains six times more sand than the 1:6 mortar. D The term richer refers only to mortar colour.

Question 27 ప్రశ్న 27

Consider the following statements about cement mortar:
1. Workability, cohesiveness and water retentivity are important fresh-mortar properties.
2. Mortar selection should account for masonry loading and environmental exposure.
3. A richer cement-sand proportion generally contains more cement relative to sand than a leaner proportion.
4. Maximum water content should always be used because additional water necessarily increases mortar strength.

Which statements are correct?

A 1 and 2 only B 1, 2 and 3 only C 2, 3 and 4 only D 1, 2, 3 and 4

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