Test 29 - Aggregate IS Specifications and Engineering Selection

Question 1 ప్రశ్న 1

Which statement correctly describes the present Indian Standard framework for aggregates used in normal structural concrete?

A IS 383:2016 specifies requirements for coarse and fine aggregates, while relevant parts of IS 2386 prescribe test methods. B IS 2386 Part 1 is the product specification for all concrete aggregates and IS 383 applies only to cement. C IS 383 applies only to natural river sand and excludes crushed and manufactured aggregates. D All aggregate properties are governed exclusively by IS 456 without separate aggregate specifications.

Question 2 ప్రశ్న 2

Which combination correctly matches aggregate quality activity with the relevant Indian Standard?

A Sampling – IS 2430; particle size and shape – IS 2386 Part 1; specific gravity and absorption – IS 2386 Part 3; mechanical properties – IS 2386 Part 4 B Sampling – IS 2386 Part 4; particle size – IS 2430; specific gravity – IS 2386 Part 7; mechanical properties – IS 2386 Part 1 C Sampling – IS 383 only; particle shape – IS 2386 Part 3; absorption – IS 2386 Part 5; mechanical properties – IS 2386 Part 8 D All four activities are covered only by IS 2386 Part 2

Question 3 ప్రశ్న 3

A fine aggregate gives percentage passing values of 100, 96, 80, 68, 45, 20 and 5 on the 10 mm, 4.75 mm, 2.36 mm, 1.18 mm, 600 µm, 300 µm and 150 µm sieves respectively. Which IS 383 grading zone does it satisfy?

A Zone I B Zone II C Zone III D Zone IV

Question 4 ప్రశ్న 4

A fine aggregate otherwise fits Grading Zone II, but 62 percent passes the 600 µm sieve. Can the general IS 383 grading tolerance be invoked to classify it as Zone II?

A Yes, because any sieve may exceed its zone limit by 5 percent. B Yes, provided its fineness modulus is below 3.0. C No, because the general grading tolerance does not apply to the 600 µm sieve. D No, because no grading tolerance is permitted on any sieve.

Question 5 ప్రశ్న 5

Which set of percentage-passing values satisfies the principal IS 383 grading requirements for nominal 20 mm graded coarse aggregate?

A 40 mm: 100%; 20 mm: 96%; 10 mm: 50%; 4.75 mm: 8% B 40 mm: 95%; 20 mm: 82%; 10 mm: 60%; 4.75 mm: 15% C 40 mm: 100%; 20 mm: 75%; 10 mm: 15%; 4.75 mm: 2% D 40 mm: 90%; 20 mm: 100%; 10 mm: 70%; 4.75 mm: 20%

Question 6 ప్రశ్న 6

Why would a nominal 20 mm aggregate having 45 percent passing the 10 mm sieve be consistent with graded aggregate but not with nominal 20 mm single-sized aggregate?

A Graded 20 mm aggregate permits 25–55 percent passing 10 mm, whereas single-sized 20 mm aggregate permits only 0–20 percent. B Single-sized aggregate requires exactly 100 percent passing 10 mm. C Graded aggregate cannot contain any material smaller than 20 mm. D The distinction depends only on geological source and not grading.

Question 7 ప్రశ్న 7

An all-in aggregate of nominal 20 mm size gives percentage passing values of 100 at 40 mm, 97 at 20 mm, 45 at 4.75 mm, 25 at 600 µm and 4 at 150 µm. What is the correct assessment under the corresponding IS 383 grading envelope?

A It satisfies the stated all-in aggregate grading requirements. B It fails because no more than 10 percent may pass 4.75 mm. C It fails because at least 50 percent must pass 600 µm. D It can only be classified as single-sized coarse aggregate.

Question 8 ప్రశ్న 8

A concrete producer combines 60 percent Fine Aggregate A, having 40 percent passing the 600 µm sieve, with 40 percent Fine Aggregate B, having 70 percent passing that sieve. What percentage of the blend will pass 600 µm?

A 46 percent B 52 percent C 55 percent D 110 percent

Question 9 ప్రశ్న 9

A 2500 g coarse aggregate sample contains 450 g flaky particles. After removing those particles, the remaining 2050 g contains 410 g elongated particles. What is the combined flakiness and elongation index using the IS 383 sequential procedure?

A 18 percent B 20 percent C 36.4 percent D 38 percent

Question 10 ప్రశ్న 10

A crushed coarse aggregate has a combined flakiness and elongation index of 41 percent. No relaxation has been approved by the engineer-in-charge. What is the normal IS 383 compliance decision?

A Accept it because the maximum is 45 percent. B Reject it because the normal maximum combined index is 40 percent. C Accept it whenever the impact value is below 30 percent. D Reclassify it automatically as fine aggregate.

Question 11 ప్రశ్న 11

A coarse aggregate is proposed for a concrete pavement wearing surface. Its ACV is 29 percent, AIV is 28 percent and Los Angeles abrasion value is 31 percent. Which assessment is correct?

A It satisfies all three requirements. B It fails only the crushing-value requirement. C It fails only the impact-value requirement. D It fails only the Los Angeles abrasion requirement.

Question 12 ప్రశ్న 12

Aggregate is proposed for M70 concrete and gives an aggregate crushing value of 21.5 percent and an aggregate impact value of 22.5 percent. What is the correct assessment under the special IS 383 requirement for M65 and above?

A Both values comply because each is below 30 percent. B The ACV complies but the AIV fails the 22 percent maximum. C The AIV complies but the ACV fails. D Neither crushing nor impact limits apply to high-strength concrete.

Question 13 ప్రశ్న 13

An aggregate for non-wearing structural concrete has an aggregate crushing value of 34 percent. The subsequent ten percent fines test gives a load of 56 kN. Considering this IS 383 mechanical requirement alone, what is the appropriate conclusion?

A It can satisfy the stated requirement because when ACV exceeds 30 percent the ten percent fines test is used, with a minimum required load of 50 kN. B It must fail automatically because all concrete aggregates have an absolute ACV maximum of 30 percent. C It passes only if the ten percent fines load is below 50 kN. D The ten percent fines test is applicable only to fine aggregate.

Question 14 ప్రశ్న 14

Which set correctly states the normal maximum mechanical values for aggregate used in concrete wearing surfaces under IS 383?

A ACV 30%; AIV 30%; Los Angeles abrasion value 30% B ACV 45%; AIV 45%; Los Angeles abrasion value 50% C ACV 22%; AIV 22%; Los Angeles abrasion value 22% for every grade D ACV 30%; AIV 45%; Los Angeles abrasion value 50%

Question 15 ప్రశ్న 15

Which combination correctly gives IS 383 limits for material finer than the 75 µm sieve in uncrushed natural fine aggregate, crushed stone sand, mixed sand and manufactured fine aggregate respectively?

A 3%, 15%, 12%, 10% B 1%, 3%, 10%, 15% C 3%, 10%, 15%, 12% D 10%, 15%, 3%, 1%

Question 16 ప్రశ్న 16

A natural coarse aggregate contains 1.4 percent material finer than the 75 µm IS sieve. If the applicable IS 383 maximum is 1 percent, which conclusion is correct?

A It satisfies the limit because coarse aggregate may contain up to 3 percent fines. B It fails the stated fines requirement. C It automatically becomes fine aggregate. D It passes whenever its specific gravity exceeds 2.5.

Question 17 ప్రశ్న 17

A manufactured aggregate has water absorption of 6 percent and is not recycled concrete aggregate or recycled aggregate. Which IS 383 assessment is correct?

A It complies because all manufactured aggregates may have up to 10 percent absorption. B It fails the normal 5 percent maximum water-absorption requirement. C It complies provided its grading is Zone II. D Water absorption is not specified for manufactured aggregate.

Question 18 ప్రశ్న 18

A recycled concrete aggregate has water absorption of 8 percent. Which statement most accurately reflects the IS 383 provision?

A It is necessarily rejected because no aggregate may exceed 5 percent absorption. B It may be permitted under the recycled-aggregate provision, subject to pre-wetting or saturation before batching and mixing. C It is automatically acceptable without any moisture correction. D Its water absorption must be reduced chemically to exactly 5 percent.

Question 19 ప్రశ్న 19

Which combination correctly states additional general IS 383 requirements for manufactured aggregates?

A Total alkali as Na2O equivalent ≤0.3%; total sulphate as SO3 ≤0.5%; water-soluble chloride ≤0.04%; water absorption normally ≤5% B Total alkali ≤3%; sulphate ≤5%; water-soluble chloride ≤0.4%; water absorption ≤15% C Only specific gravity is controlled; chemical constituents are unrestricted. D Water-soluble chloride must be at least 0.04% and water absorption at least 5%.

Question 20 ప్రశ్న 20

A manufactured aggregate has water-soluble chloride content of 0.05 percent but satisfies its grading and mechanical requirements. What is the correct compliance decision if the applicable maximum is 0.04 percent?

A Accept it because satisfactory mechanical properties override chloride content. B Reject it as non-conforming to the stated water-soluble chloride requirement. C Accept it whenever the concrete is above M40 grade. D Reclassify it automatically as natural aggregate.

Question 21 ప్రశ్న 21

A copper-slag fine aggregate has a specific gravity of 3.6. Which statement correctly reflects the special IS 383 provision?

A It must always be rejected because every aggregate is limited absolutely to a specific gravity of 3.2. B Copper slag with specific gravity up to 3.8 may be used for permitted part replacement, provided the average specific gravity of the resulting fine aggregate does not exceed 3.2. C Copper slag is treated as cement and is outside all aggregate requirements. D Specific gravity has no role in the manufactured-aggregate provisions.

Question 22 ప్రశ్న 22

A fine aggregate fails the organic-impurity colour screening test but produces relative mortar strengths of 97 percent at 7 days and 96 percent at 28 days compared with the control. What is the correct IS 383 interpretation?

A It must be rejected solely because the colour test failed. B It may satisfy the performance-based organic-impurity criterion because relative strength is at least 95 percent at both ages. C It fails because relative strength must exceed 100 percent. D It can be accepted only if its fineness modulus is exactly 2.5.

Question 23 ప్రశ్న 23

Which statement correctly interprets the IS 383 soundness provisions for aggregate to be used in concrete liable to frost action?

A The standard gives guide losses after five cycles, but the actual allowable limits are to be agreed between purchaser and supplier for the relevant exposure. B Every aggregate for every concrete application has an unconditional sodium sulphate maximum of exactly 10 percent. C Soundness requirements are replaced completely by aggregate crushing value. D Soundness is assessed only from specific gravity.

Question 24 ప్రశ్న 24

An aggregate passes grading, shape, crushing and abrasion requirements but is known to contain a potentially alkali-reactive constituent. Which engineering decision is most appropriate?

A Accept it automatically because mechanical compliance proves chemical durability. B Assess the alkali-aggregate reaction risk separately and apply the relevant IS 383 evaluation or mitigation requirements before acceptance. C Ignore reactivity whenever aggregate crushing value is below 30 percent. D Increase aggregate size until the reactive constituent becomes harmless.

Question 25 ప్రశ్న 25

Two compliant aggregate sources are available for reinforced concrete. Source X is well graded but highly absorptive and angular, while Source Y has similar strength but lower absorption and more favourable shape. Which selection principle is most appropriate?

A Select solely from crushing value because all other aggregate properties are irrelevant. B Consider grading, moisture corrections, workability, shape, durability and concrete trial performance together rather than ranking the aggregates from one property alone. C Always choose the aggregate with the highest water absorption. D Always choose the most angular aggregate regardless of workability.

Question 26 ప్రశ్న 26

A proposed aggregate for an M70 pavement has combined flakiness and elongation index 38 percent, ACV 21 percent, AIV 23 percent and Los Angeles abrasion value 28 percent. Which result prevents compliance on the stated mechanical and shape data?

A Combined flakiness and elongation index B Aggregate crushing value C Aggregate impact value D Los Angeles abrasion value

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