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है”ह”ह

IS 2720-2 (1973): Methods of test for soils, Part 2:Determination of water content [CED 43: Soil and FoundationEngineering]

IS : 2720 ( Part II ) - 1173(Reaffirmed 2010)

Indian StandardMETHODS OF TEST FOR SOILS

PART II DETERMINATION OF WATER CONTENT

( Second Revision)

Fifth Reprint FEBRUARY 1993

UDC 624.131.431.3

Copyright 1973

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

Gr 5 July 1913

IS I 2720 ( Part II ) • 1973

Indian StandardMETHODS OF TEST FOR SOILS

PART II DETERMINATION OF WATER CONTENT

( Second Revision)Soil Engineering Sectional Committee, DDO 23

Chairmanhop DIMEIB MOHAN

Rejw,sInting

Central Building Research Institute (CSIR),Roorkee

University of Jodhpur, JodhpurCementation Co Ltd, Bombay

Irrigation & Power Research Institute, AmritsarIn personal capacity ( P 820) New ~/ipor,)

Calcutta 53)Hindustan Construction Co, BombayIrri,ation Research Institute, Khagaul, PatnaIndian Geotechnical Society, New DelhiCentral Water & Power Commission, New Delhi

SHR! A. H. DIVANJ! ( AllmuJII )SaRI O. P. MALHOTRA Buildinp at Road Research Laboratory, Public

Worb Department, Government of Punjab(.Continrutl ",. pa" 2 )

Central Building Research Institute ( CSIR),Roorkee

SHRI D. R. NARAHARI ( Aillmat, )JOINT DIRECTOR RUBARCH (FE). Railway Board ( Ministry of Railways)

RDSaDEPUTY DJREaroR RESEARCH

( SOIL ~iECHANICI),RDSO ( A.luma16)SHRI G. KUItCKBLMANN Rodic'Foundation Engineering Ltd; anti Hazarat It

Co, Bombay

SURt A. G. DAITIDARSHRt R. L. DEWANDR G. S. DHILLONDIRBCTOR. ( CENTRAL SOIL

MaCHANICI RESEARCH STATION)DEPUTY DIRKCTOR ( CSMRS) (AltmuJtI)

Pao. R. N. DOORA Indian Institute of Technology, New DelhiSHRI S. K. GULHATI ( AltmuJu)

SR.' V. G. HEDGE National Buildings Organization, New DelhiSRal J. P. SHARMA ( AltmuJII )

DRJQ,BAL ALI Engineering Research Laboratory, HyderabadSnar K. R. SAXBNA ( Altemat«)

SHRI G. S. JAIN

M"n6er,PRoP ALAY SIMOHDR A. BANaRJa&

SHRI S. GUPTA (AltmuJII)SHRIB.B.L.BRATNAOARSHRI K. N. DADINA

(I) Ctlp~II'" 1973

BUR.EAU OF INDIAN STANDARDS

This publicatioD is protected under the 111111t111 Copyright Acl (XIV of 1957) andreproduction in whole or in part by anI means except with written pormiuioD of thopublisher ahall be deemed to be aD lDrriDlemeDt or copyriaht UDder the said Act.

•

IS a2720( Part U ) • 1973

Dealen

of Uttar

RtpreslntingConcrete Association of India, Bombay

Institution of Engineers ( India), CalcuttaAll India Instruments Manufacturer. &

Association. BombaySHRr V. K. VAlUDEVAN ( Allerna', )

SHRI H. G. VERUA Public Works Department, GovernmentPradesh

SHRl D. C. CHATURVEDI ( Altnnat, )SRRI D. A]tTHA SIUHA, Director General. lSI (&.fJjficio Mtmbn)

Director ( Civ Eogg )

MAJ K. M. S. SAKASlSHRI P. PUTlIUIOAMANI

SECRETARYOa SHAMSHBR. PRAKASHSHRI H. D. SHARMA

SHal S. N. SINHASHal A. S. BlSHNOI ( Alternate)

SUPERINTBNDINO ENGINEER (PLAN- Concrete & Soil Research Laboratory, Public WorksNINO AND OSSION CIRCLE) Department, Government of Tamil Nadu

EXECUTIVE ENGINEER INC".~RGE

( SOIL MaCHANICS &. RUEARCHDIVISION) (Alternat,)

SHRJ C. G. SWAMINATHANSRRI lie C. VEaUA

( ContinUldfrom pail J )

Member,SHRJ M. A. MEHTA

SHRI T. M. MENON (Alternat' )SURI T. K. NATAIlAJAN Central Road Research Institute ( CSIR ), New DelhiRUBARCH QnlC&R Buildings & Roads Research Laboratory" Public

Works Department, Government of PunjabEngineer-In-Chief'e Branch, Army Headquarters

(AlterlUJtI )Central Board of Irrigation & Power, New DelhiUniversity of Roorkee, RoorkeeIrrigation Research Institute, RoorkeeRoads Wing ( Ministry of Shipping & Transport)

S,c"tarySHRI G. RAMAN

Deputy Director ( Civ Bngg ), lSI

Soil Testing Procedures and Equipment Subcommittee, BDC 23: 3

Univenity ofJodhpurtJodhpurPROP Auy SINOH

Mnnb"sDR R. K. BHANDARI Central Road Research Institute ( CSIR), New DelhiSHill T. N. BHAROAVA Roads Wing (Ministry of Shipping & Transport)

SHRI A. S. BISKNOI (AlurNlu)Da A. K. CHATTa.JEB Public Worb Department, Government of Uttar

PradeshSaRI R. L. DawAN Irrigation Research Institute, Khagaul, PatnaDmBaroa ( CSMRS ) Central Water &. Power Commission. New Delhi

DEPUTY Dot.oroR ( CSMRS) (Allmlall)SHIll H. K. GURA Geologists' Syndicate Private Ltd, Calcutta

SHill N. N. BHA1TACBAIlVYA ( Allmld16 )SHIU S. K. GULATI Indian-Institute of Technology.~New DelhiSURI O. P. MALHOTRA Buildings &. Road Reseateh Laboratory, Public Worb

Department, Government of PunjabK ' I' )SHU R.. •AOOAaWA:.. •~fmUaII

2

AUGUST 1982AMENDMENT NO.1TO

IS I 2720 ( Part II )-1973 METHODS OP TESTFOR SOILS

PART II DETERMINATION OF WATER CO.TENT

( Second Re~i.ionJAlteratlo••

( Pall 4, elaus« f.l ):

a) Informal tall/I,ftrsl column - Substitute the followinr for the eJEist­ing matter:

c 425,.m IS Sieve2-mm IS Sieve4-75-mm IS Sieve9-50-mm IS Sieve19-mm IS Sieve37 eS-mm IS Sieve t

b) Nol, I - Substitute the following for the existing Dote:• NOT. I - For size. or sieves, $1' IS: 460 ( Part I )-1978t ' •

(Pog, 4, fODI.nol, with "t ' mark) - Substitute the following (or theexisting foot-note:

• tSpecification for t~,t sleves: Part I Wire cloth tett .ieftl (J«n~ rIR,. ). •

( PtJg, 8, "GUS, )6.1 ):a) 1,,!ormmla61t, first column - Substitute the roJlowing for the exist­

ing matter:

, 2-mm IS Sieve19-mm IS Sieve •

b) Not, 1 --- Substitute the following for the existing note:

• NOT. I - For size. or sieves, ,. IS : 460 ( Part I )-1978- I.

( Pall 8,!tJot-,.ot, willa • • • mark ) - Substitute the followinl for theexisting foot-note:

• -Specification for t.,t .ievf'S: Part I Wire cloth tftC .ievn ( '-rrtJiriM). '

1

( Pdl' t4, eltJIU, 28.', NoI, ) - Substitute the following Cor the exist.ing note:

• No,.. - If the sample i, bulky. reverie the above fl.cem~nt. 'hat ii, put thesample in the chamber and the absorbent in the cup. n the ~.Ie or clayey lOilsand paltel, place the 3 smaller and one bigler .teel ball. in 'he bod, alonl withthe ablorbrnt. t

( PilI' 15, ,laas, 28.4, NOlI) - Substitute the following for the exilt­ing note:

• NOT. -- When Iteel ball. are u••d, place the three Imall., and ODe bil,erballl in the body alanK with the absorbent and the .ample In the cup and leal upthe unit al ulual. Hold the rapid moi,ture meter vertical with the cup downward.and .Itow the absorbent with the balJI to r.11 into the cup. Shake the unit upand down vi,oroully in thi. pOlltion for about 15 seconds. Now invert the unit andallow the material to fall into the body. Now holdin, the unit horisonta' rotate itfor 10 seeonds 10 th.t the ball. rolled round the in.lde circumference or tbe body.Ret' (or 20lecondl. Repeat the • hove evele until the I.u~e re.dins i. conltlat( uluaJly this r.kes 4 to 8 min). Note the re.dlnl a. usual.

(BDe 2~ )

2Reprography Unit. DIS, New Delhi. India

IS &2720 ( Part D ) • 1975

Indian StandardMETHODS OF TEST FOR SOILS

PART II DETERMINATION OF WATER CONTENT

( Second Revision)

o. FOR E WO RD

0.1 This Indian Standard, ( Part II) (Second Revision) was adopted bythe Indian Standards Institution on 22 March 1973, after the draf] finalizedl>y the Soil Engineering Sectional Committee had been approved by theCivil Engineering Division Council.

0.2 With a view to establish uniform procedures for the determination ofdifferent characteristics of soils and also for facilitating comparativestudies of the results, the Indian Standards Institution is bringing out thisIndian Standard methods of test for soils (IS: 2720) which will bepublished in parts.

0.3 This part was first published in 1964 and revised in 1969 toinclude two rapid field methods for the determination of water contentin soils. In this second revision, rapid determination of water contentwith infra-red lamp torsion balance moisture meter and rapid deter­mination of water content from the gas pressure developed by the react ionof calcium carbide with the free water content of the soil have beenincluded.

0.4 In the formulation of this standard due weightage has been given tointernational co-ordination among the standards and practices prevailingin different countries in addition to relating it to the practices in the fieldin this country.

0.5 In reporting the result of a test or. analysis made in accordance withthis standard. if the final value, observed or calculated, is to be roundedoff, it shall-be done in accordance with IS: 2-1960-.

SECTION I OVEN.DRYING METHOD(STANDARD METHOD)

I. SCOPE1.1 This method covers the determination of water content of soilsexpressed as a percentage of the oven-dry weight.

·Rwea Cor rounding off .americal VUUeI (""11I).

IS I 2720 ( Part D ) • 1973

2.TBRMlNOLOOY2.0 For the purpose of this standard, the definitions given in IS: 2809·1972­shall apply.

3. APPARATUS

3.1 eoatala... - Any suitable non-corrodible air-tight container.

3.2 Balaace - of sufficient sensjtivity to weigh the soil samples to anaccuracy of 0-04 percent of the weight of the soil taken fQr the test( $" 4.1 ).

3.3 Ove. - thermostatically controlled, with interior of non-corrodingmaterial to maintain the temperature at 110 :I: 5°0.

3.4 De.lecator - A desiccator with any suitable desiccating agent.

4. SOIL SPECIMEN

425-micron IS Sieve2-mm IS Sieve4:75-mm IS SieveIO-mm IS Sieve20-mm IS Sieve40-mm IS Sieve

NOTa 1-- For Mel of.evet, ,. IS: 460-1962t.NOTa 2 - Drier the 1011, the peater mall be the quaotity of the IOU tUm.Non 3- Water COGtea.t .pecImeD should be dilc:arded and mould not be aaed In

any otber tCitl.

4.1 The soil specimen taken shall be representative of the soil mass. Thesize of the specimen selected depends on the quantity required for goodrepresentation, which is influenced by the gradatioa and the maximumsize of particles, and on the accuracy of weighing, The following q uanti­ties are recommended for general laboratory use:

Si~, of Partin,s Minimum a-lUJnti9 ofSoilMor, nan. 90 P"eml Passin, Specim,,, to11, Ta!,nlor T1St

MtUJ in g

2550

200300500

1 000

5. PROCEDURE5.1 Clean the container with lid, dry and weigh (WI.). Take the requiredquantity of the soil specimen in the container crumbled and placed looaely,

-Olo..ry of tenDS aDd .,mboll reladaa to 1011 eqtaeen. (jim,..,.).tSpecification for tat .eva ( rrrIiIItI).

IS I 2720 (Part II) • 1973

and weigh with lid ( WI). Then keep it in an oven with the lid removed,and maintain the temperature of the oven at 110 :I: SoC ( see Note). Drythe specimen in the oven for 24 h. Every time the container is taken outfor weighing. Replace the lid on the container and cool the container ina desiccator. Record the final mass ( WI) of the container with lid withdried soil sample.

Non - Oven-drying at JJO ± 5°C doe. not result in reliable water content valuesfor toil containin, IYplum or other mineral. having loosely bound water of hydrationor for soil containIng sIgnificant amounts of organic material. Reliable water contentYalu~ for these lOiI. can be obtained by drying in an oven at approximately 60 to BOGC.

6. CALCULATION

6.1 The percent of water content shall be calculated as follows:

W, - WI 00w== 'xlW.- WI

where

w - water content percent,

WI = mass of container with lid with wet soil in g,

WI ::: mass of container with lid with dry soil in g, and

WI === mass of container with lid in g.

7. REPORT

7.1 The water content (rD) of the soil shall be reported to two significantfigures.

7.2 The results of the test shall be suitably recorded. A recommendedpr, forma for this record is given in Appendix A.

SECTION 1 SAND-BATH METHOD (SUBSIDIARY METHOD)

8. SCOPE

8.1 This method covers the determination of the water content of a soil asa percentage of its dry mass. It is intended as a rapid alternative to themethod given in Section I but is less accurate and more suitable as a fieldtest. The method shall not be used jf it is suspected that the soil containsa large proportion of gypsum calcareous matter or organic matter.

t. APPARATUS

'.1 COataJa_ ..... any suitable non-corrodible air-tight container,

5

IS I 2720 ( Part D ) • 1973

9.2 Heat-Re.i.taat Tray - of suitable metal and about 5 to 7 em deep.

9.3 Balaace - of sufficient sensitivity to weigh the soil samples to anaccuracy of 0-4 percent of the mass of the soil taken for the test.

9.4 Sand-Bath - of sui table size and containing clean sand to a depth ofat least 3 em.

9.5 EquipDlent for Heati. the Saud-Bath - kerosene stove or spiritlarnp,

9.6 Palette I{Dife or Steel Spatula - a convenient size is one having ablade 10 em long and 2 em wide.

9.7 Scoop - a convenient size is one about 20 em long and 10 em wide.

10. SOIL SPECIMEN

10.1 The mass of soil specimen taken for the test shall be in accordancewith 4.1.

11. PROCEDURE

11.1 Clean the container with lid or the tray, as the case may be, dry andweigh ( WJ ) . Take the required quantity of the soil specimen in thecontainer crumbled and placed loosely and weigh (n'I). Add a fewpieces .of white paper if necessary (ste Note). Place the container withthe lid removed or the tray ()O the sand-bath and heat the sand-bath.Care shall be taken not to get the sand-bath too hot, During heating, thespecimen shall be turned frequently' and thoroughly with the palette knifeto assist the evaporation of water, care being taken to see that no soil islost in the process; Dr'J the specimen to constant mass indicated by thedifference between two consecutive masses of the container with lid or thetray with the dried specimen taken at suitable intervals after initial drying,being a maximum of 0-1 percent of the original mass of the soil specimen.WhCll drying is complete, remove the container or the tray from the sand­bath, 'cool and weigh ( W,), The container should be weighed with lid.

NOT" - Avoid overheatin~. A convenient method of detecting overheating of thesoil is by the use of small pieces of white paper mixed with the soil. Overheatinlis indicated if the paper turns brown.

12. CALCULATION

12.1 The percentage of water content shall be calculated at follows:

WI - W, 100Was lA' W X

'Ya - 1

6

18 I 2720 ( Part II ) • 1173

where

w = water content percent,

WI =- mass of container with lid ( or tray) with wet soil in g,

Wa .. mass of container with lid (or tray) with dry soil in g,and

WJ := mass of container with lid (or tray) in g.

13. REPORT

13.1 The water content and the results of tests shall be reported inaccordance with 7.1 and 7.2.

SECTION 3 ALCOHOL METHOD (SUBSIDIARY METHOD)

14. SCOPE

It.l This method covers the determination of the water content of a soilas a percentage of its dry mass. It is intended as a rapid alternative tothe method given in Section 1 but is less accurate and is more suitable asa field test. Since methylated spirit is used, care shall be taken againstrisk of fire. TIle method shall not be used if the soil contains a largeproportion of clay, gypsum, calcareous matter or organic matter.

15. APPARATUS

15.1 Evaporadag Di.h-- 10 to 15 em in diameter.

15.2 Palette Kalfe or Steel Spatala - having a blade 10 em long and2 em wide.

15.3 BaIaDce ...... of sufficient aensitivity to weigh the soil samples to anaccuracy or 0·4 percent of the mass of the soil taken for the test.

15.4 Methylated Spirit

16. SOiL SPECIMEN

16.1 The soil. specimen taken shall be representative of the soil mass.The size of the specimen selected depends on the quantity required forgood representation, which is influenced by the gradation and the maxi­mum size of particles, and on the accuracy of weighing. The following

7

IS I 2720 ( Part 0 ) • 1973

quantities are recommended for general use:

SkI ofParti,lllM0" Than 90 p,,'11Il Passi"g

2-mm IS Sieve20-mm IS Sieve

Minimum QpQ"ti~ ofSoilSp"imm to b« T den for Test

Mass in g

30

300

NoTS 1- For sizes of Iieves. s" IS: 460·1962-.

NOTB 2 - Drier the soil, the greater ahall be the quantity of the soil taken.

NOTE 3 - Water content samples should be discarded and should not be used in an.,other testl.

17. PROCEDURE

17.1 Clean the evaporating dish, dry and weigh ( W1 ) . Take the requiredquantity of the soil specimen in the evaporating dish and weigh ( J¥: ).Pour over the soil methylated spirit at the rate of about one millilitre torevery gram of soil taken so that the soil is well covered. Wark the methy­lated spirit well into the soil with the palette knife and break up any largelumps of soil. Place the evaporating dish on a surface which will not beaffected by heat and ignite the methylated spirit. Stir the soil constantlywith the spatula or knife, care being taken to see that none of the soil islost. After the methylated spirit has burnt away completely allow thedish to cool and weigh it with the contents ( Wa).

18. CALCULATION

18.1 The percentage of water content shall be calculated as follows:

w .. W, - WlI X 100W.- WI

whereIII .. water content percent,

WI =- mass of dish with wet soil in g,WI == mass of dish with dry soil in g. andWI -= mass of dish in g.

19. REPORT

19.1 The water content and the results of tests shall be reported inaccordance with 7.1 and 7.2.

-Specification for ttlt sieva (fWIiI,tl).

8

IS I 2720 ( Part n ) • 1973

SECTION 4 RAPID DETERMINATION OF WATERCONTENT WITH INFRA-RED LAMP TORSION

BALANCE MOISTURE METER

20. SCOPE

20.1 This section describes a method for rapid determination of watercontent of soils employing a device providing infra-red lamp for dryingand torsion balance for getting of percentage of water on wet basis from ascale, and the results obtained are convertible to water content on drybasis.

Non - The water estimation with this method take. 15 to 30 min depending uponthe type of soil and quantity of water present, Plastic soils might take about 30 min.The reproducibility of readings i. within .0·25 percent. The probable error isabout. 0·3 percent water content in case of granular soils and about 0-8 to J per­cent in case of clay••

21. APPARATUS

21.1 Infra-red LaD1p aDd Tor.loa Balaace Mol.ture Meter- Themoisture meter is illustrated in its essential details in Fig. 1 and 2.

21.1.1 The equipment should be of two main parts, the infra-red lamp,and the torsion balance. TIle infra-red radiation should be provided by250 walt lamp built in the balance for use with an alternating current220...230 V, 50 cycle, single phase mains supply. Provision should be madeto adjust tlie input voltage to the infra-red lamp to control the heat fordrying of specimen. A suitable thermometer graduated from 40 to ISOaCshould be provided for ascertaining the temperature of drying in the panhousing. The weighing mechanism, a torsion balance, should have abuilt in magnetic damper. Thebalance scale should be divided in termsof water percentages, from 1 to 100 percent water content in 0'2 percentdivisions.

21.2 Palette Kaife or Steel Spatala - having a blade 10 em long and2 em wide.

22. SOn. SPECIMEN

22.1 The soil specimen taken shall be representative of the soil mass. Thespecimen should weigh 25 g. As this moisture meter is calibrated to use25 g of soil, the maximum size of particle present in the specimen shall beless than 2 mm,

23. PROCEDURE

2'.1 Keep the test samples always in suitable containers so that the watercontent to be determined is not affected by ambient conditions.

9

IS I 2720 ( Part D ) • 1"73

TO IR LAMP

TO 230 V SINGLEPHASE 50 c/.AC MAINS SUPPL

J. Bale2. Pan housingS. Pan4. On-off switch5. Wire tensioner6. Initial adjustment knob7. Left-band wire Srip8. Gear9. Dampilll magnet

10. DaJDping vaneII. Balan~e arm12. Stopper

•

D,#riltiota13. Calibrated drum14. Wire grip ror balance15. Gear16. Torsion wire17. Pointer18. Right-hand wire grip19. Drum drive knob20. Index mark21. Lock22. Variac knob (for heat control)28. Thermometer29. Thermometer bracket

FlO. 1 TORSION BALANCE MOISTUU METER. (0-100 PERCENT) ­PLAN (COVER REMOVED)

10

lSI 2720 ( Part D ) • 1173

29

tTO ~30 V SINbl~--........._ ......-----_..............._--~PHASE 50 cis

AC MAINS SUPPLY

1. Base

2. Pan housing

4. On-off'swilch

6. Initial adjustment knob

19. Drum drive knob

22. Variac knob ( (or heat control)

23. Cover

24. Lamp houling

25. Lifting handle

26. Viewing lens

27. Locking screw

28. Thermometer

29. Thermometer bracket

SO. Indicating lamp

Flo.2 TORSION BALANCE MOISTURE METER (0-100 PERCENT) ­FRONT Vmw.

11

IS I 2720 ( Part II ) • 1973

23.2 Set the 100 percent scale division of the calibrated drum to alignwith the index mark with the help of drum drive knob.

23.3 Witll the pan placed on the pivot, check that the pointer is alignedwith the index line and the 100 percent scale division. If not, set thepointer with the help of initial setting knob.

23.4 Rotate the drum drive knob anti-clockwise and bring the 0 percentscale division in line with the index mark, thus prestressing the wirethrough an amount equal to 100 percent (this represents the amount ofunbalance). The pointer will now be above the index mark.

23.5 Raise the lamp housing and carefully distribute the test materialevenly on the sample pan until the pointer returns to the' index mark( approximately 25 g of the material will be needed in one operation).

23.6 Lower the lamp housing and switch on the infra-red lamp with thehelp of the switch provided on the left-hand side. Insert the thermometer'in ,Its socket and bracket. Adjust the variac control knob between 95 and100 on the scale .if it is desired that the temperature of drying is around110°C. The sample will now begin to lose water and the pointer willrise above the index.

NOTa - Keep a watch on the column of mercury on the thermometer when thethermometer records a temperature of 105°0. control the variac in such a manner thatthere is no more rise in the temperature beyond 110°0 and the temperature in thehOUling is maintained at 110 • 5°C. If for a particular sample, the temperature i. Cobe higher or lower than J100 e, the variac control knob can be adjusted accordingly.

23.7 To determine the percentage reduction of mass at any instant, rotatethe drum scale by turning the drum drive knob until the pointer returnsto the index. Read the percentage directly from the scale. The percentwater which is read from the scale is the percent water based upon theinitial mass of the sample, that is, the wet mass of the sample.

23.8 The criterion for taking the final reading is that the pointer shouldremain steady on the index mark which shows that the sample has driedto constant mass. Note the drum scale reading against the pointer whichis the percent water on the total mass taken. Remove the thermometerfrom its bracket.

23.9 Repeat steps 23.1 to 23.8 with a fresh sample using a cool and cleanpan.

24. CALCULATION

24.1 From the water" content (m) as obtained on the moisture balancescale. the water content ( w) on the dry weight basis shall be calculated ufollows:

mw - 100 _ m X 100 percent

12

IS 12720 (Part It) .1973

SECTION 5 RAPID DETERMINATION OF WATERCONTENT FROM THE GAS PRESSURE DEVELOPED

BY THE REACTION OF CALCIUM CARBIDEWITH THE FREE WATER OF THE SOIL

25. SCOPE

25.1 This section describes a method for rapid determination of watercontent from the gas pressure developed by the reaction of calcium car­bide with the free water of the soil. From the calibrated scale of thepressure gauge the percentage of water on total (wet) mass of soil isobtained and the same is converted to water content on dry mass of soil.

26. APPARATUS

26.1 Metallic Pre••ure Ve••el- with clamp for scaling cup, and agauge calibrated in percentage water content ( se« Fig. 3 ).

26.2 CoaDterpoi.ecl BalaDee - for weighing sample as shown in Fig. 3.

26.3 Scoop -- for measuring absorbent ( calcium carbide).

26.4 ODe Bottle of the Ab.orbeat ( CalciaDi Carbide)

26.5 ODe CleaDiaI Bnuh

26.6 Steel BaU. - three steel balls of about 12-5 mm diameter arid onesteel ball of 25 mm diameter.

27. son. SPECIMEN

27.1 Sand requires no special preparation. Coarse powders may beground and pulverized. Cohesive and plastic soils and material are testedwith addition of steel balls in the pressure vessels. This test requires about6 g of. soil sample.

28. TEST PROCEDURE

28.1 Set up the balance. Place sample in pan till the mark on the balancearm mass lines up with the index mark.

28.2 Unclamp the clamping screw of the instrument sufficiently to movethe Uvclamp off the cup. Lift off the cup. Check that cup and body areclean; otherwise clean it using a brush.

28.3 Hold the body horizontal and gently deposit one level scoopful ofabsorbent (calcium carbide) halfway inside the chamber. Then lay thechamber down without disturbing the absorbent charge. Transfer the

IS I 2720 ( Part n )· 1973

10

sI

,

D"cripti,n

I. Scoop2. Balance bale3. Index mark

4. Balance arm

5. Stirrup6. Pan

D,scri/ltion

7. Gauge 0-50%8. Body9. Cup

10. U-clamp11. Clamp screw

FIG.. 3 RApID MOISTURB METER

soil weighed out as above (rom the pan to the cup. Holding cup andchamber approximately horizontal bring them together without disturb­ing sample or absorbent, bring the U-clamp round and clamp the cuptightly into place.

NOTa - Ifth~ sample is bulky reverse the above placements, that ii, put the sample inthe chamber and the absorbent in the cup. I n the case of clayey soils and pastes, Placethe , .maJJer steel balls in the cup along with the sample and larger one in the bodyalonl with the absorbent.

21.4 With gauge downwards (except when the steel balls are used) shakethe moisture meter up and down vigorously for 5 seconds, then quicklyturn it so that the gauge is upwards, give a tap to the body of the moisturemeter to ensure that all the contents fall into the cup. Hold the rapid

If

IS I 2720( Part n )•1973

moisture meter downwards, again shake (or 5 seconds, then turn it with~auge upwards and tap. Hold for one minute. Repeat this for a third time.Once more invert the rapid moisture meter and shake up and down tocool the gas, Turn tile rapid moisture meter with the gauge upwards anddial horizontal held at chest height. When the needle comes to rest takethe reading. Tile readings on the meter are the percentages of water onthe wet mass basis.

NOTE - When steel baU. are used place the , .maUer ball. in the cup aloDI withthe soil and the larger one in the body along with the absorbent and seal up the unitas usual. Hold the rapid moisture meter vertical so that the material in the cup raIl.into the body. Now holding the unit horizontal rotate it for 10 seconds so that theballs arc rolled round the inside circumference of the body. Rest for 20 seconds.Repeat the rotation-rest cycle until the gauge reading is constant (Ulually thil takes4 to 8 min). Note the reading as usual.

28.5 Finally release the pressure slowly (away from the operator) byopening the clamp screw and taking the cup out, empty the contents andclean the instrument with a brush.

29. CALCULATION

29.1 From the water content ( m ) obtained on the wet mass basi. as thereading on the rapid moisture meter, the water content ( w ) on the drymass basis shall be calculated as follows:

mw = ( 100 _ m) X 100 percent

NOTa ...... The absorbeDt i. highly IUlCeptibJe to absorption of moiaturtt and So shallnot be exposed to atmosphere; as a result the absorbent suffers deterioration and willgive results 00 'he lower side. Replace the lid of the abaorbent container firmly at soonAI the required amount of the absorbent Cor a test i. taken from the bottle. The abtor­bent .der. deterioration with time.

15

IS t 2720 ( Part II ) • 1973

APPENDIX A

( Clause 7.2 )

PRO FORMA FOR RECORD OF RESULTS OF TESTFOR THE DETERMINATION OF WATER CONTENT OF SOIL

Details of soil sample:

Method of test adopted :

1. Container N().

Tested by:

Oven drying:

Sand-bath:

Alcohol:

2. Mass of container and wet soil WI' in g

3. Mass of container arid dry soil ~V3' in g

4. Mass of container WI' in g

5. Mass of dry soil ( Wa - WI)' in g

----- --~------------._------:---------6. MaS! of moisture ( WI - W" J, in g

1. Water content w = ~t - WW~ X 100%3 - 1

16

( ConlinUltlfrom /J'JII 2 )

M,mh"sSURI G. S. JAIN

IS I 2720 ( Part II ) • 1973

Re!Jr,smIin,Central Building Research Institute ( CSIR ).

RoorkeeSHRI AMAH SINOH ( AllnfttJII )

DR V. V. S. RAO United Technical Consultant. Pvt Ltd, New DelhiSRRI K. K. GUPTA (Alll1nal,)

MAJ K. M. S. SAHAst Engineer-in..Chie('s Branch, Army HeadquartersPROP R. B. SINOH Banaras Hindu University, BanarasSHRI II. C. VERMA Associated Instrument Manufacturers (India) Pvt

Ltd, New DelhiSURI M. N. BALIOA ( Alternat« )

17

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