மார்ச்சு 25, 2023 இதழ்
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ஆற்று மணல் – கட்டுரை

Typical compressive strength of concrete:

The following result show the behavior of manufactured sand and riverbed sand when used in concrete.

With using riverbed sand [all proportions are weight]

Cement- 50kg

River sand – 75kg

Agg.20mm – 75 kg

Agg.12mm – 37.5kg

Water – 19 liters

Compressive strength achieved after 7- days curing 44.1mpa with using manufactured sand [ all proportions are weight]

Cement – 50kg

Artificial sand – 70 kg

Agg. 20mm – 80kg

Agg. 12mm – 35kg

Water – 19 liters

Compressive strength achieved after 7-days curing- 46.8 mpa.

Technical specification – comparison between manufactured sand riversand.

S.No Property River sand Manufactured sand Remarks
1 Shape Spherical particle Cubical Particle Good.
2. Gradation Cannot be Controlled Can be controlled
3 Particle passing 75 micron Presence of silt shall be less than 3% Presence of Dust particle shall be less than 15% Limit 3% for unrushed and limit 15% for crushed sand.
4. Silt and organic impurities Present [Retard the setting compressive strength] Absent Limit of 5% for uncrushed & 2% for crushed sand.
5. Specific gravity 2.3 – 2.7 2.5 – 2.9 May vary.
6. Water absorption 1.5-3% 2-4% Limit 2%
7. Ability to hold surface moisture Upto 7% Upto 10%
8. Grading zone [FM] Zone II, III FM 2.2 – 2.8 Zone- III FM 2.6-3.0 Recommends zone II for mass concrete.
9. Soundness [Sodium sulphate-ss & magnesium sulphate-ms] [5 cycles] Relatively less sound [Ex>5] Relatively sound [Ex>5] Limit 10% SS and 15% ms
10. Alkali silica relativity 0.002-0.01 0.001-0.008 Limit 0.1% expansion
S.No Property River sand Manufactured sand Remarks
1 Work ability & its retention Good & good retention Less & less retention Control of fires apply water absorption correction use of plasticisers
2 Setting Normal Comparativery Faster Apply water absorption correction use retarders.
3 Compressive Strength Normal Marginally higher As shown above
4 Permeability Poor Very poor
5 Cracks May be Send to surface crack Early curing & protection of Fresh concrete.

Behavior of manufactured Sand & River sand when used in concrete.

SIEVE ANALYSIS RIVER SAND & MANUFACTURED SAND

IS SIEVE River sand % age passing Manufactured sand % age passing % age passing per single sized aggregate of normal sand [IS 383-1970] Zone II
4.75mm 99.25 99.75 90 to 100
2.36mm 93.50 78.25 75 to 100
1.18mm 48.00 52.00 55 to 90
600micron 21.00 38.00 35 to 54
300micron 04.00 21.00 08 to 30
150micron 0.05 5.00 0 to 10

Typical sieve Analysis: Comparison of River sand & Manufacture sand

IS Sieve % of passing [Riversand] % of passing manufactured sand Zone II (As Per IS:383)
4.75mm 100 100 90-100
2.36mm 99.7 90.7 75-100
1.18mm 89 66.2 55-90
600micron 60.9 39.8 35-59
300micron 17.7 25.5 8-30
150micron 3.1 9.9 0-20
75micron Max 3

Zone II

Max 15

Zone II

Max 15

 

Zone II Zone II: The gradation of manufactured sand can be contracted at crushing plant.

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