Test 18 - Cement Fineness, Consistency and Setting Time

Question 1 ప్రశ్న 1

Which combination correctly matches the cement property with the applicable part of IS 4031?

A Dry-sieve fineness – Part 1; Blaine fineness – Part 2; Standard consistency – Part 4; Initial and final setting times – Part 5 B Dry-sieve fineness – Part 4; Blaine fineness – Part 5; Standard consistency – Part 1; Setting time – Part 2 C Dry-sieve fineness – Part 3; Blaine fineness – Part 4; Standard consistency – Part 6; Setting time – Part 1 D All four properties are determined exclusively under IS 4031 Part 5

Question 2 ప్రశ్న 2

In the dry-sieving method of IS 4031 (Part 1), cement fineness is represented by:

A The percentage of cement passing a 4.75 mm sieve B The mass percentage of residue retained on the standard 90 micrometre IS sieve C The penetration of a Vicat plunger into cement paste D The time required for cement mortar to reach 28-day strength

Question 3 ప్రశ్న 3

A 100 g cement sample leaves 4.5 g residue on the 90 micrometre sieve after the prescribed dry-sieving test. What is the percentage residue?

A 2.25 percent B 4.5 percent C 9.0 percent D 22.2 percent

Question 4 ప్రశ్న 4

What is the fundamental principle of the Blaine air-permeability method for determining cement fineness?

A Measuring resistance to penetration of a needle into cement paste B Measuring the permeability of a prepared cement bed to air and relating it to specific surface area C Measuring the mass of cement dissolved in water D Determining only the largest individual cement particle

Question 5 ప్రశ్న 5

Cement X has a Blaine specific surface of 360 m²/kg and Cement Y has 240 m²/kg. If the two cements are otherwise comparable, which statement is most appropriate?

A Cement X is generally finer according to the Blaine test. B Cement Y is necessarily finer because its numerical value is lower. C Both cements must have identical particle-size distributions. D Blaine specific surface has no relationship with cement fineness.

Question 6 ప్రశ్న 6

Which effect is generally associated with increasing the fineness of otherwise similar Portland cement?

A Slower early hydration and lower early strength in every case B Greater reactive surface, generally faster early hydration and potentially higher early heat evolution C Complete elimination of water demand D Permanent prevention of cement setting

Question 7 ప్రశ్న 7

Why is excessive cement fineness not automatically desirable merely because finer cement can hydrate more rapidly?

A Greater fineness can increase early reaction rate, heat evolution and water demand and also requires additional grinding energy. B Fine cement cannot react chemically with water. C Only coarse cement is capable of developing strength. D Fineness affects colour but no engineering property.

Question 8 ప్రశ్న 8

Under IS 4031 (Part 4), a cement paste has standard consistency when the Vicat plunger penetrates to:

A Exactly the bottom of the mould B A point 5 to 7 mm from the bottom of the Vicat mould C A point 20 to 25 mm from the bottom of the mould D Only 2 mm below the top surface

Question 9 ప్రశ్న 9

A 400 g cement sample requires 118 g of water to produce a paste of standard consistency. What is the standard consistency P?

A 25.0 percent B 27.5 percent C 29.5 percent D 33.9 percent

Question 10 ప్రశ్న 10

During a standard-consistency trial, the Vicat plunger stops 12 mm above the bottom of the mould. What adjustment is generally required for the next fresh trial paste?

A Use less water because the paste is too fluid. B Use somewhat more water because the paste is too stiff to achieve the required penetration. C Change to the final-setting needle without altering the paste. D Accept 12 mm as the standard-consistency criterion.

Question 11 ప్రశ్న 11

Which statement about standard consistency is technically correct?

A It is numerically identical to the water-cement ratio required for every concrete mix made with that cement. B It is a standardized paste property used as a reference for laboratory cement tests and is not itself a concrete mix-design water-cement ratio. C It is determined from the 28-day strength of concrete cubes. D It is the percentage of cement retained on a 90 micrometre sieve.

Question 12 ప్రశ్న 12

Which Vicat-apparatus component is correctly matched with its principal use?

A Standard plunger – consistency; initial-setting needle – initial set; needle with annular attachment – final set B Standard plunger – final set; annular attachment – fineness; initial-setting needle – soundness C Standard plunger – compressive strength; initial-setting needle – Blaine fineness; annular attachment – consistency D All three components are used only for cement soundness

Question 13 ప్రశ్న 13

The standard consistency of a cement is P = 30 percent. Under IS 4031 (Part 5), how much water is required to prepare the setting-time test paste using 400 g of cement?

A 85 g B 102 g C 120 g D 141 g

Question 14 ప్రశ్న 14

For determination of initial and final setting times under IS 4031 (Part 5), the stopwatch is started:

A When the filled Vicat mould is first placed under the needle B At the instant water is added to the cement C When the initial-setting needle first fails to penetrate D After the cement has remained in the mould for 30 minutes

Question 15 ప్రశ్న 15

Under IS 4031 (Part 5), the initial setting time is reached when the Vicat initial-setting needle:

A Penetrates completely through the paste to the base plate B Fails to pierce the test block to a point 5.0 ± 0.5 mm measured from the bottom of the mould C Makes no contact with the top of the paste D Produces a high-gloss impression on the cement surface

Question 16 ప్రశ్న 16

What observation defines final setting under the Vicat method of IS 4031 (Part 5)?

A Both the central needle and the annular attachment make clear impressions. B The central needle makes an impression on the surface but the annular attachment fails to make an impression. C The needle penetrates completely through the mould. D The cement reaches its specified 28-day compressive strength.

Question 17 ప్రశ్న 17

Which statement best distinguishes initial setting time from final setting time?

A Initial setting marks a standardized stage in loss of plasticity, while final setting represents a later standardized stage of rigidity; neither means hydration is complete. B Initial and final setting are always identical. C Final setting means the cement has attained its full 28-day strength. D Initial setting is measured by the Blaine apparatus while final setting is measured by a sieve.

Question 18 ప్రశ్న 18

Water is added to an ordinary OPC sample at 10:00 AM. The initial-setting criterion occurs at 10:42 AM and the final-setting criterion occurs at 3:20 PM. What are the setting times, and do they satisfy the ordinary OPC limits of at least 30 minutes initially and not more than 600 minutes finally?

A 42 minutes and 320 minutes; both requirements are satisfied B 42 minutes and 520 minutes; only the initial requirement is satisfied C 32 minutes and 300 minutes; both requirements are satisfied D 20 minutes and 320 minutes; only the final requirement is satisfied

Question 19 ప్రశ్న 19

An ordinary OPC sample has an initial setting time of 27 minutes and a final setting time of 410 minutes. Which assessment is correct under the ordinary OPC setting-time requirements?

A It complies because the final setting time is satisfactory. B It fails the initial-setting-time requirement even though the final-setting-time result is within the permitted maximum. C It fails only because final setting must exceed 600 minutes. D Both results comply because setting time has no specification limits.

Question 20 ప్రశ్న 20

An ordinary OPC sample has an initial setting time of 55 minutes and a final setting time of 625 minutes. What is the correct interpretation?

A Both setting-time requirements are satisfied. B The initial-setting requirement fails but the final-setting requirement passes. C The initial-setting requirement passes but the final-setting requirement fails. D The cement automatically becomes Rapid Hardening Portland Cement.

Question 21 ప్రశ్న 21

An ordinary OPC sample has a Blaine specific surface of 218 m²/kg. If the applicable IS 269 minimum is 225 m²/kg, what is the correct conclusion?

A It satisfies the fineness requirement because lower specific surface means finer cement. B It fails the stated Blaine fineness requirement. C It automatically qualifies as PPC. D Blaine specific surface is unrelated to cement specifications.

Question 22 ప్రశ్న 22

Why are temperature, moisture conditions and standardized preparation procedures controlled during consistency and setting-time tests?

A Because penetration and hydration behaviour can be influenced by test conditions, and uncontrolled variation would reduce comparability of results B Because cement properties are completely independent of temperature and moisture C Because the purpose is only to change the colour of the paste D Because standardized testing requires every cement to set at exactly the same time

Question 23 ప్రశ్న 23

Which statement about the effect of temperature on cement setting is generally correct, while recognizing that standardized laboratory tests use controlled conditions?

A Higher temperature commonly accelerates hydration and can shorten setting time, although the exact effect depends on the cement system. B Higher temperature always increases setting time without exception. C Temperature has no possible effect on cement hydration. D Setting time depends only on the colour of the cement.

Question 24 ప్రశ్న 24

Which statement about final setting time is correct?

A Final setting means that hydration has completely ceased. B Final setting means that the cement has achieved its full specified compressive strength. C Final setting is a standardized stage of rigidity, after which hydration and strength development continue. D Final setting is determined from the percentage residue on a 90 micrometre sieve.

Question 25 ప్రశ్న 25

Consider the following statements about fineness, consistency and setting of cement:
1. The Blaine method expresses fineness in terms of specific surface area.
2. Standard consistency is determined with the Vicat plunger rather than the setting-time needle.
3. The setting-time paste under IS 4031 (Part 5) is prepared using 0.85 times the water required for standard consistency.
4. Final setting signifies completion of all subsequent cement hydration and strength development.

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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