Test 20 - Cement Tests and Test Apparatus

Question 1 ప్రశ్న 1

Which combination correctly matches the physical test of hydraulic cement with the relevant part of IS 4031?

A Dry-sieve fineness – Part 1; Blaine fineness – Part 2; soundness – Part 3; standard consistency – Part 4; setting time – Part 5; compressive strength – Part 6 B Dry-sieve fineness – Part 2; Blaine fineness – Part 1; soundness – Part 5; standard consistency – Part 3; setting time – Part 6; compressive strength – Part 4 C Dry-sieve fineness – Part 3; Blaine fineness – Part 4; soundness – Part 6; standard consistency – Part 5; setting time – Part 1; compressive strength – Part 2 D All six properties are determined under IS 4031 Part 1

Question 2 ప్రశ్న 2

Match each cement test with the form in which its principal result is reported:
1. Dry-sieve fineness
2. Blaine fineness
3. Standard consistency
4. Le Chatelier soundness

P. Percentage water by mass of cement
Q. Specific surface area per unit mass
R. Expansion in millimetres
S. Percentage residue on the specified sieve

A 1-S, 2-Q, 3-P, 4-R B 1-Q, 2-S, 3-R, 4-P C 1-P, 2-R, 3-Q, 4-S D 1-R, 2-P, 3-S, 4-Q

Question 3 ప్రశ్న 3

What does the dry-sieving fineness test under IS 4031 (Part 1) primarily measure?

A The proportion of comparatively coarse cement particles represented by residue on the 90 micrometre IS sieve B The total chemical lime content of the cement C The compressive strength of cement mortar D The penetration resistance of cement paste

Question 4 ప్రశ్న 4

A 100 g cement sample leaves 3.8 g residue on the 90 micrometre sieve after the prescribed dry-sieving test. What is the percentage residue?

A 1.9 percent B 3.8 percent C 7.6 percent D 26.3 percent

Question 5 ప్రశ్న 5

Which statement best describes the principle of the Blaine air-permeability apparatus?

A It measures the resistance to air flow through a prepared bed of cement and relates this behaviour to specific surface area. B It determines cement soundness by boiling a split mould. C It determines initial setting by penetration of a needle. D It crushes cement mortar cubes to determine compressive strength.

Question 6 ప్రశ్న 6

Which statement correctly distinguishes the dry-sieve and Blaine methods of measuring cement fineness?

A Dry sieving measures the coarse residue on a specified sieve, whereas the Blaine method estimates specific surface area from air permeability. B Both methods directly determine the complete particle-size distribution. C Dry sieving measures specific gravity while Blaine measures setting time. D The Blaine method measures only particles larger than 90 micrometres.

Question 7 ప్రశ్న 7

In the standard-consistency test using the Vicat apparatus, the required consistency is reached when the standard plunger penetrates the paste to:

A A point 5 to 7 mm from the bottom of the mould B Exactly the bottom of the mould C A point 20 mm below the top surface regardless of mould height D A point where the annular final-setting attachment makes no impression

Question 8 ప్రశ్న 8

A 400 g cement sample requires 114 g of water to reach standard consistency. What is the standard consistency P?

A 25.0 percent B 28.5 percent C 30.0 percent D 35.1 percent

Question 9 ప్రశ్న 9

During a consistency trial, the Vicat plunger stops 10 mm above the bottom of the mould. What should generally be done in the next fresh trial?

A Use somewhat more water because the paste has not permitted sufficient penetration. B Use less water because the paste is already too fluid. C Accept the result because 10 mm is the specified standard-consistency criterion. D Change directly to the Le Chatelier apparatus without determining P.

Question 10 ప్రశ్న 10

Match the test with the prescribed water relationship based on standard consistency P:
1. Initial and final setting-time paste
2. Le Chatelier soundness paste
3. Compressive-strength mortar

P. 0.78P of the standard-consistency water
Q. 0.85P of the standard-consistency water
R. (P/4 + 3)% of the combined mass of cement and standard sand

A 1-Q, 2-P, 3-R B 1-P, 2-Q, 3-R C 1-R, 2-P, 3-Q D 1-Q, 2-R, 3-P

Question 11 ప్రశ్న 11

The standard consistency of a cement is 28 percent. How much water is required for a setting-time test paste prepared with 400 g of cement?

A 87.4 g B 95.2 g C 112.0 g D 134.4 g

Question 12 ప్రశ్న 12

For the Vicat setting-time test, from what instant is the elapsed setting time measured?

A From the instant water is added to the cement B From the instant the mould is placed beneath the needle C From the first needle penetration reading D From the time the specimen is finally set

Question 13 ప్రశ్న 13

Which observation represents the initial-setting criterion in the Vicat test?

A The initial-setting needle fails to penetrate beyond a point 5.0 ± 0.5 mm from the bottom of the mould. B The standard plunger reaches exactly the bottom of the mould. C The annular attachment makes no impression but the central needle does. D The mortar cube fails under compression.

Question 14 ప్రశ్న 14

Which observation represents final setting in the Vicat test?

A The central needle makes an impression, but the annular attachment fails to make an impression on the surface. B Both the needle and annular attachment penetrate completely through the paste. C The standard-consistency plunger reaches 5 to 7 mm from the bottom. D The cement mortar cube reaches its 28-day strength.

Question 15 ప్రశ్న 15

Which sequence is most appropriate for determining the setting time of a cement when its standard consistency is not yet known?

A Determine P by the consistency test → prepare fresh paste with 0.85P water → fill the Vicat mould → make the prescribed setting-needle observations with time measured from water addition B Measure final set first → determine P → dry sieve the hardened paste → calculate initial set C Prepare the setting paste with an arbitrary water content → determine P after final setting → correct the result mathematically D Perform the Le Chatelier test → crush the specimen → use its failure load as the setting time

Question 16 ప్రశ్న 16

Which sequence correctly represents the basic Le Chatelier soundness procedure?

A Prepare the prescribed paste → fill the split mould between glass plates → condition it under water → measure the indicator spacing → apply the prescribed boiling cycle → cool and remeasure → calculate the increase in spacing B Crush a mortar cube → sieve the fragments → measure Vicat penetration → calculate expansion C Determine Blaine fineness → polish the specimen → immerse it in oil → determine final setting D Heat dry cement powder directly and report the maximum temperature as soundness

Question 17 ప్రశ్న 17

In a Le Chatelier test, the indicator spacing is 17.5 mm before the boiling stage and 23.0 mm after boiling and cooling. What is the measured expansion?

A 4.5 mm B 5.5 mm C 17.5 mm D 40.5 mm

Question 18 ప్రశ్న 18

Which statement correctly compares the Le Chatelier and autoclave soundness tests?

A Both assess dimensional stability, but the autoclave method uses severe high-pressure steam exposure and is especially useful for revealing slower expansive tendencies such as those associated with magnesia. B Le Chatelier determines compressive strength while the autoclave determines setting time. C The two tests are simply alternative methods of measuring Blaine fineness. D Autoclave testing measures only the colour change of cement.

Question 19 ప్రశ్న 19

Which combination correctly describes specimen preparation for the standard cement compressive-strength test under IS 4031 (Part 6)?

A Cement and standard sand are mixed in a 1:3 mass ratio, cast into approximately 70.6 mm cubes and compacted using the prescribed vibration procedure. B Neat cement paste is cast into 150 mm concrete cubes with coarse aggregate. C Cement and local soil are mixed in equal proportions and tested without curing. D Dry cement powder is compressed directly between steel plates without making mortar.

Question 20 ప్రశ్న 20

Why is IS standard sand used in the cement compressive-strength test instead of arbitrary locally available sand?

A To minimize variability due to grading, mineralogy and particle characteristics so that differences in measured strength more reliably reflect cement performance B Because local sand can never be used in construction C Because standard sand prevents cement hydration D To ensure that the laboratory mortar is identical to every field concrete mix

Question 21 ప్రశ్న 21

For a cement-strength test, 200 g cement and 600 g standard sand are used. If P = 28 percent, how much water is required using (P/4 + 3)% of the combined mass of cement and sand?

A 56 g B 64 g C 80 g D 112 g

Question 22 ప్రశ్న 22

A standard cement-mortar cube having a loaded face approximately 70.6 mm × 70.6 mm fails under a load of 210 kN. What is its approximate compressive strength?

A 21.1 MPa B 33.7 MPa C 42.1 MPa D 59.4 MPa

Question 23 ప్రశ్న 23

Three cement-mortar cubes tested at the same age give compressive strengths of 41.6 MPa, 42.3 MPa and 42.8 MPa. What is their average strength?

A 41.6 MPa B 42.0 MPa C 42.2 MPa D 42.8 MPa

Question 24 ప్రశ్న 24

Why must the compressive strength obtained from IS 4031 cement-mortar cubes not be treated as the characteristic compressive strength of concrete made using that cement?

A The cement test uses a standardized mortar system, whereas concrete strength also depends on water-cement ratio, coarse and fine aggregates, admixtures, compaction, curing and mix proportions. B Cement mortar strength is always exactly twice concrete strength. C Concrete strength depends only on cement colour. D The cement test and every structural concrete mix have identical constituents and proportions.

Question 25 ప్రశ్న 25

Which of the following test-apparatus or test-purpose pairs is INCORRECT?

A Vicat apparatus – standard consistency and setting-time determinations B Le Chatelier apparatus – cement soundness by expansion measurement C Blaine air-permeability apparatus – cement specific-surface fineness D Standard cement-mortar vibration machine – determination of cement density

Question 26 ప్రశ్న 26

Consider the following statements about standard cement testing:
1. Standard consistency should be determined before tests whose water quantity is expressed in terms of P.
2. The setting-time test and Le Chatelier soundness test use different fractions of the standard-consistency water.
3. The standard cement compressive-strength test uses a 1:3 cement-to-standard-sand mortar rather than ordinary structural concrete.
4. A satisfactory final-setting time automatically proves that the cement is sound.

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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