Test 19 - Cement Soundness, Strength and Physical Properties

Question 1 ప్రశ్న 1

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

A Soundness – Part 3; compressive strength of hydraulic cement other than masonry cement – Part 6; density – Part 11 B Soundness – Part 6; compressive strength – Part 11; density – Part 3 C Soundness – Part 5; compressive strength – Part 2; density – Part 6 D All three properties are determined under IS 4031 Part 3

Question 2 ప్రశ్న 2

What does soundness of cement primarily describe?

A The ability of hardened cement paste to resist undesirable delayed expansion after setting B The time taken by fresh cement paste to reach initial set C The colour uniformity of dry cement powder D The maximum concrete slump obtainable from the cement

Question 3 ప్రశ్న 3

Which constituents are most commonly associated with harmful delayed expansion and unsoundness of Portland cement when present in excessive reactive form?

A Free lime and magnesia B C-S-H and standard sand C Quartz aggregate and mixing water D Calcium silicate hydrate and entrained air only

Question 4 ప్రశ్న 4

What is the basic measurement obtained in the Le Chatelier soundness test?

A The increase in distance between the indicator points of the split mould after the prescribed conditioning and boiling treatment B The compressive failure load of a cement mortar cube C The specific surface area of cement particles D The penetration depth of the Vicat initial-setting needle

Question 5 ప్రశ్న 5

In a Le Chatelier soundness test, the distance between the indicator points is 14.0 mm after the initial water-conditioning stage and 20.0 mm after boiling and cooling. What is the measured expansion?

A 3.0 mm B 6.0 mm C 14.0 mm D 34.0 mm

Question 6 ప్రశ్న 6

An ordinary OPC sample shows a Le Chatelier expansion of 11 mm. If the applicable maximum under IS 269 is 10 mm, what is the correct interpretation?

A It satisfies the soundness requirement because expansion should exceed 10 mm. B It fails the stated Le Chatelier soundness requirement. C It automatically qualifies as OPC 53. D It should be accepted solely if its compressive strength is high.

Question 7 ప్రశ్న 7

What is the principal purpose of the autoclave soundness test of cement?

A To accelerate potentially harmful expansive reactions under high-temperature and high-pressure steam conditions B To determine only the initial setting time C To determine cement particle size by air flow D To measure the slump of concrete

Question 8 ప్రశ్న 8

Which statement most appropriately compares the Le Chatelier and autoclave soundness methods?

A Both assess dimensional stability, but the autoclave method provides a more severe accelerated exposure and is particularly useful in revealing delayed expansive tendencies including those associated with magnesia. B Both are methods of determining cement compressive strength. C Le Chatelier measures concrete slump while the autoclave measures cement colour. D The two methods always produce numerically identical results expressed in millimetres.

Question 9 ప్రశ్న 9

The standard consistency of a cement is P = 30 percent. For a Le Chatelier soundness test using 100 g of cement, the paste is prepared with 0.78P water. How much water is required?

A 18.0 g B 23.4 g C 30.0 g D 38.4 g

Question 10 ప్రశ్న 10

Which statement correctly describes the compressive-strength test of cement under IS 4031 (Part 6)?

A It determines cement strength using standardized cement-sand mortar cubes rather than ordinary structural concrete cubes. B It determines cement strength by crushing dry cement powder directly. C It determines only the tensile strength of neat cement paste. D It requires coarse aggregate to be included in every test specimen.

Question 11 ప్రశ్న 11

What is the cement-to-standard-sand mass ratio used in the IS 4031 (Part 6) compressive-strength test for hydraulic cement other than masonry cement?

A 1:1 B 1:2 C 1:3 D 1:6

Question 12 ప్రశ్న 12

For one standard cement-strength cube, 200 g cement and 600 g standard sand are used. If the cement has standard consistency P = 30 percent, how much water is required using the IS 4031 (Part 6) expression (P/4 + 3)% of the combined mass of cement and sand?

A 60 g B 72 g C 84 g D 120 g

Question 13 ప్రశ్న 13

What is the nominal size of the cube mould used in the IS 4031 (Part 6) cement compressive-strength test?

A 50 mm B 70.6 mm C 100 mm D 150 mm

Question 14 ప్రశ్న 14

A standard 70.6 mm cement-mortar cube fails under a compressive load of 215 kN. Using a loaded area of approximately 70.6 × 70.6 mm², what is the approximate compressive strength?

A 21.6 MPa B 33.0 MPa C 43.1 MPa D 60.8 MPa

Question 15 ప్రశ్న 15

Three standard mortar cubes tested at the same age give compressive strengths of 42.6 MPa, 43.2 MPa and 44.1 MPa. What is their average compressive strength?

A 42.6 MPa B 43.0 MPa C 43.3 MPa D 44.1 MPa

Question 16 ప్రశ్న 16

Why should the compressive strength obtained from a standard cement mortar cube not be treated as the characteristic compressive strength of concrete made using that cement?

A Concrete strength also depends on water-cement ratio, aggregates, mix proportions, admixtures, compaction and curing, whereas the cement test uses a standardized mortar system. B Cement mortar cubes and concrete always have identical strengths. C Concrete strength depends only on cement colour. D The cement test includes exactly the same coarse aggregate and mix proportions as every concrete structure.

Question 17 ప్రశ్న 17

Why must curing conditions be carefully controlled for cement mortar specimens used in compressive-strength testing?

A Because hydration and strength development depend on moisture and temperature, and inconsistent curing would make test results incomparable. B Because curing permanently stops cement hydration. C Because curing affects only the colour of the mortar cubes. D Because dry storage always gives the maximum possible standardized strength.

Question 18 ప్రశ్న 18

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

A To minimize variation in grading and sand characteristics so that differences in test strength primarily reflect cement performance B Because natural sand cannot be used in any construction work C Because standard sand chemically prevents cement hydration D To make the mortar identical to every concrete mix used in practice

Question 19 ప్రశ్న 19

What is the principal purpose of mechanical vibration during moulding of standard cement-mortar cubes?

A To compact the mortar reproducibly and reduce harmful entrapped voids before strength testing B To initiate flash setting deliberately C To increase the cement grade by chemical reaction D To replace the curing process

Question 20 ప్రశ్న 20

Under IS 4031 (Part 11), determination of cement density is based principally on:

A Determining the volume displaced by a known mass of cement in a suitable non-reactive liquid using a calibrated flask B Measuring Vicat needle penetration into cement paste C Measuring the residue on a 90 micrometre sieve D Crushing a 150 mm concrete cube

Question 21 ప్రశ్న 21

A cement sample has a mass of 64.0 g and produces a net liquid displacement of 20.4 cm³ in a density test. What is its approximate density?

A 2.14 g/cm³ B 3.14 g/cm³ C 3.84 g/cm³ D 4.14 g/cm³

Question 22 ప్రశ్న 22

If the density of a cement is 3150 kg/m³ and the reference density of water is taken as 1000 kg/m³, what is its approximate specific gravity?

A 0.315 B 1.50 C 3.15 D 31.5

Question 23 ప్రశ్న 23

Which statement correctly distinguishes cement density from the bulk density of loose cement powder?

A Cement density refers to the volume of the cement material itself, whereas loose bulk density also includes the void space between powder particles. B The two quantities are necessarily identical. C Bulk density excludes all voids between cement grains. D Cement density is measured only from a concrete cube.

Question 24 ప్రశ్న 24

Match the physical property with the relevant IS 4031 test part:
1. Drying shrinkage
2. Density
3. Air content of hydraulic cement mortar
4. False set

P. Part 14
Q. Part 10
R. Part 12
S. Part 11

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

Question 25 ప్రశ్న 25

Which statement about drying shrinkage of cement-based material is most accurate?

A It refers to dimensional contraction associated with moisture loss from hardened paste or mortar under specified drying conditions. B It is the same phenomenon as initial setting. C It always causes expansion rather than contraction. D It is determined by the Le Chatelier split mould.

Question 26 ప్రశ్న 26

Consider the following statements about cement soundness, strength and physical properties:
1. A cement can have high compressive strength and still fail a soundness requirement.
2. Cement compressive strength under IS 4031 Part 6 is determined on standard cement-sand mortar cubes rather than ordinary structural concrete cubes.
3. Specific gravity is dimensionless, whereas density has units.
4. Final setting time and soundness are two names for the same physical property.

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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