Test 34 - Fresh Concrete Workability Tests

Question 1 ప్రశ్న 1

Which statement correctly describes the current IS 1199 framework for testing the consistency of fresh concrete?

A IS 1199 (Part 2):2018 includes slump, Vee-Bee, compacting-factor, degree-of-compactability and flow-table methods, while special tests for fresh self-compacting concrete are covered in Part 6. B IS 1199 Part 2 covers only compressive-strength testing of hardened concrete. C IS 1199 Part 6 specifies aggregate crushing and impact tests. D The slump, Vee-Bee and compacting-factor tests are governed only by IS 383.

Question 2 ప్రశ్న 2

A normal plastic concrete mix at site is expected to have a slump of about 80 mm, and a rapid routine consistency check is required. Which test is the most appropriate first choice?

A Vee-Bee test B Slump test C Los Angeles abrasion test D Aggregate crushing-value test

Question 3 ప్రశ్న 3

Which set correctly gives the principal internal dimensions of the slump mould under IS 1199 (Part 2):2018?

A Height 300 mm, base diameter 200 mm, top diameter 100 mm B Height 200 mm, base diameter 200 mm, top diameter 130 mm C Height 300 mm, base diameter 150 mm, top diameter 75 mm D Height 400 mm, base diameter 200 mm, top diameter 200 mm

Question 4 ప్రశ్న 4

Which sequence correctly describes the principal filling and mould-removal procedure in the current slump test?

A Fill in two layers, apply 10 strokes per layer and lift the mould after 30 seconds. B Fill in three approximately equal layers, tamp each layer 25 times and lift the mould vertically in 5 ± 2 seconds without lateral or twisting motion. C Fill in four layers, vibrate each for 30 seconds and rotate the mould during removal. D Fill the mould without compaction and determine the mass of concrete.

Question 5 ప్రశ్న 5

After lifting a 300 mm high slump mould, the highest point of a true-slump concrete specimen is 225 mm above the base plate. What slump should be reported?

A 25 mm B 75 mm C 225 mm D 300 mm

Question 6 ప్రశ్న 6

What range of measured slump is stated as the normal applicability range of the slump test in IS 1199 (Part 2):2018?

A 0 to 50 mm B 10 to 210 mm C 100 to 300 mm D 340 to 620 mm

Question 7 ప్రశ్న 7

During a slump test, the concrete shears to one side instead of giving a true slump. What is the appropriate action under the current method?

A Report the vertical drop immediately as a valid true slump. B Add water to the same specimen and repeat. C Take another sample and repeat the test; if two consecutive tests shear or collapse, report the test as invalid for that concrete. D Convert the observed shear into a compacting factor mathematically.

Question 8 ప్రశ్న 8

What does the Vee-Bee consistometer test principally measure?

A The time required under vibration to remould concrete from a conical-frustum shape into a cylindrical form. B The percentage air content of concrete under pressure. C The mass loss of aggregate in a rotating drum. D The compressive strength of a concrete cube.

Question 9 ప్రశ్న 9

Under IS 1199 (Part 2):2018, the ordinary Vee-Bee test may be unsuitable when the measured Vee-Bee time is:

A Between 5 and 30 seconds B Less than 5 seconds or greater than 30 seconds C Exactly 15 seconds D Between 10 and 20 seconds only

Question 10 ప్రశ్న 10

Concrete X has a Vee-Bee time of 8 seconds, while Concrete Y has a Vee-Bee time of 22 seconds. Assuming comparable testing conditions, which interpretation is correct?

A Concrete Y is more workable because a larger Vee-Bee time indicates easier remoulding. B Concrete X is more workable because it requires less vibration time to remould. C Both concretes necessarily have identical consistency. D Vee-Bee time has no relationship to concrete consistency.

Question 11 ప్రశ్న 11

A very stiff, dry, essentially zero-slump concrete such as roller-compacted concrete has to be assessed. Which provision in IS 1199 (Part 2) is especially relevant?

A Modified Vee-Bee consistometer procedure B Ordinary flow-table test for 340–620 mm spread C Standard slump test alone regardless of the result D Le Chatelier soundness test

Question 12 ప్రశ్న 12

What is the basic principle of the compacting-factor test?

A Determining the ratio of the mass of partially compacted concrete to the mass of the same volume of fully compacted concrete. B Measuring the vertical slump of concrete after removing a cone. C Measuring the spread after 15 flow-table drops. D Determining the time required for concrete to reach initial set.

Question 13 ప్రశ్న 13

In a compacting-factor test, the net mass of partially compacted concrete is 16.8 kg and the net mass of fully compacted concrete is 19.2 kg. What compacting factor should be reported to the nearest 0.01?

A 0.78 B 0.88 C 1.14 D 1.88

Question 14 ప్రశ్న 14

Two concretes tested under identical compacting-factor conditions give values of 0.86 and 0.94. Which statement is generally correct?

A The concrete with compacting factor 0.94 is more readily compacted and has higher workability under the test. B The concrete with compacting factor 0.86 is necessarily more workable because the lower number is always better. C The two values measure only compressive strength. D A compacting factor closer to 1 indicates poorer compactability.

Question 15 ప్రశ్న 15

A very low-workability conventional concrete gives almost no meaningful differentiation in repeated slump tests. Which test is specifically described in IS 1199 Part 2 as being more precise and sensitive than slump and particularly useful for very low-workability concrete?

A Compacting-factor test B Flow-table test C Concrete cube test D Air-content test

Question 16 ప్రశ్న 16

In the degree-of-compactability test, which expression is used when h1 is the internal height of the container and h2 is the mean distance from the compacted concrete surface to the upper edge?

A c = h2/h1 B c = h1/(h1 − h2) C c = (h1 − h2)/h2 D c = h1 + h2

Question 17 ప్రశ్న 17

In a degree-of-compactability test, the internal container height h1 is 400 mm and the mean distance h2 from the compacted concrete surface to the top edge is 60 mm. What is the degree of compactability to the nearest 0.01?

A 1.06 B 1.18 C 1.47 D 6.67

Question 18 ప్రశ్న 18

Which statement correctly describes the applicability and interpretation of the degree-of-compactability test?

A The stated valid range is 1.04–1.46, and a value closer to 1 generally represents concrete requiring less compaction-induced volume reduction. B The valid range is 10–210 and a larger value always means greater slump. C Only values below 0.50 are valid. D A value of 2.0 represents ideal self-compacting concrete.

Question 19 ప్రశ్న 19

For which type of concrete is the ordinary IS 1199 Part 2 flow-table test principally intended?

A High-workability concrete having a flow spread generally between 340 and 620 mm, but not self-compacting concrete B Very dry zero-slump roller-compacted concrete only C Hardened concrete after 28 days D Only concrete with flow greater than 1000 mm

Question 20 ప్రశ్న 20

Which procedure correctly describes important steps in the IS 1199 Part 2 flow-table test?

A Fill the mould in two equal layers, tamp each 10 times, remove the mould and subject the table to 15 standardized drops before measuring spread. B Fill the mould in three layers, tamp each 25 times and measure only vertical settlement without moving the table. C Fill one layer without tamping and rotate the table for 500 revolutions. D Apply a 40-tonne compressive load and measure the resulting spread.

Question 21 ప్రశ్న 21

A flow-table test gives maximum spread dimensions d1 = 510 mm and d2 = 550 mm in perpendicular directions. What flow value should be reported?

A 510 mm B 520 mm C 530 mm D 550 mm

Question 22 ప్రశ్న 22

A fresh self-compacting concrete has to be assessed for filling ability and related SCC behaviour. Which approach is correct?

A Use only the ordinary Part 2 flow-table test because it is specifically intended for SCC. B Use the appropriate fresh-SCC tests under IS 1199 (Part 6) rather than treating the ordinary Part 2 flow-table test as the SCC test. C Use the aggregate crushing-value test. D Use only a 28-day cube test because fresh SCC does not require fresh-property assessment.

Question 23 ప్రశ్న 23

The fresh concrete contains coarse aggregate larger than 40 mm, but an IS 1199 Part 2 consistency test is required. What should be done before testing?

A Test the concrete unchanged because aggregate size has no effect on the test. B Wet-sieve the concrete through a 40 mm screen to exclude particles larger than 40 mm. C Crush all coarse aggregate until it passes the 4.75 mm sieve. D Replace the coarse aggregate with cement paste.

Question 24 ప్రశ్న 24

Why should fresh-concrete consistency tests intended for comparison be carried out at a consistent elapsed time after completion of mixing?

A Because concrete consistency changes with time owing to cement hydration and possible moisture loss. B Because concrete consistency remains exactly constant after mixing. C Because elapsed time affects only aggregate specific gravity. D Because waiting longer automatically increases slump.

Question 25 ప్రశ్న 25

Consider the following statements about fresh-concrete workability tests:
1. Slump is normally applicable for measured slumps between 10 and 210 mm.
2. A shorter Vee-Bee time generally indicates a more workable concrete than a longer time under comparable conditions.
3. Compacting factor is the ratio of partially compacted concrete mass to fully compacted concrete mass.
4. The ordinary IS 1199 Part 2 flow-table test is specifically intended as the principal test for SCC.

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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