AIM:

(i)Todeterminetheconsistencyofbituminousmaterial

(ii)Toassessthesuitabilityofbitumenforuseunderdifferentclimaticconditionsandvarioustypesofconstruction.

APPARATUS:

(i)Container:Aflatbottomedcylindricalmetallicdish55mmindiameterand35mmindepthisrequired.Ifthepenetrationisoftheorderof225ormore,dishof70mmdiameterand45mmdepthisrequired.

(ii)Needle:Astraight,highlypolished,cylindricalhardsteelrod.

(iii)Waterbath:Waterbathmaintainedat250.1C,containingnotlessthan10litresofwater,thesamplebeingimmersedtoadepthnotlessthan100mmfromtop&supportedonperforatedshelfnotlessthan50mmfrombottomofthebath.

(iv)Transferdishortray:Shouldprovidesupporttothecontainer&shouldnotrockit.Itshouldbeofsuchcapacityastocompletelyimmersecontainerduringtest.

(v)Penetrationapparatus:Shouldbesuchthatitallowsneedletopenetratewithoutmuchfriction&isaccuratelycalibratedtogiveresultsinonetenthofamillimeter.

(vi)Thermometer:Range044Candinreadableupto0.20C.

(vii)Timemeasuringdevice:Withanaccuracyoflsecond.

THEORY:

Penetrationvalueisameasureofhardnessorconsistencyofbituminousmaterial.Itistheverticaldistancetraversedorpenetratedbythepointofastandardneedleintothebituminousmaterialunderspecificconditionsofload,timeandtemperature.Thisdistanceismeasuredin

PENETRATION VALUE OF BITUMEN

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onetenthsofamillimeter.Thistestisusedforevaluatingconsistencyofbitumen.Itisnotregardedassuitableforuseinconnectionwiththetestingofroadtarbecauseofthehighsurfacetensionexhibitedbythesematerials.

PROCEDURE:

(i)Preparationoftestspecimen:Softenthematerialtoapouringconsistencyatatemperaturenotmorethan60Cfortarsand90Cforbitumenabovetheapproximatesofteningpointandstiritthoroughlyuntilitishomogeneousandisfreefromairbubblesandwater.Pourthemeltintothecontainertoadepthatleast

10mminexcessoftheexpectedpenetration.Protectthesamplefromdustandallowittocoolinanatmosphereatatemperaturebetween15to30Cforonehour.Thenplaceitalongwiththetransferdishinthewaterbathat250.1C,unlessotherwisestated.

(ii)Fillthetransferdishwithwaterfromthewaterbathtodepthsufficienttocoverthecontainercompletely,placethesampleinitandputituponthestandofthepenetrationapparatus.

(iii)Cleantheneedlewithbenzene,dryitandloadwiththeweight.Thetotalmovingloadrequiredis1000.25gms,includingtheweightoftheneedle,carrierandsuperimposedweights.

(iv)Adjusttheneedletomakecontactwiththesurfaceofthesample.Thismaybedonebyplacingtheneedlepointincontactwithitsimagereflectedbythesurfaceofthebituminousmaterial.

(i)Makethepointerofthedialtoreadzeroornotetheinitialdialreading.

(ii)Releasetheneedleforexactlyfiveseconds.

(vi)Adjustthepenetrationmachinetomeasurethedistancepenetrated.

(vii)Makeatleast3readingsatpointsonthesurfaceofthesamplenotlessthan10mmapartandnotlessthanl0mmfromthesideofthedish.Aftereachtestreturnthesampleandtransferdishtothewaterbathandwashtheneedlecleanwithbenzeneanddryit.Incaseofmaterialofpenetrationgreaterthan225,threedeterminationsoneachofthetwoidenticaltestspecimensusingaseparateneedleforeachdeterminationshouldbemade,leavingtheneedleinthesampleoncompletionofeachdeterminationtoavoiddisturbanceofthespecimen.

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PRECAUTIONS:

(i)Thereshouldbenomovementofthecontainerwhileneedlepenetratesintosample.

(ii)Thesampleshouldbefreefromanyextraneousmatter.

(iii)Theneedleshouldbecleanedwithbenzeneanddriedbeforepenetration.

OBSERVATIONS

Actualtesttemperature=C

Penetrationdialreading Test1 Test2 Test3(a)Initial(b)FinalPenetrationValueMean

RESULT:

MeanPenetrationValue=

RECOMMENDEDVALUE:

Penetrationtestisacommonlyadoptedtestonbitumentogradethematerialintermsofitshardness.A80/100gradebitumenindicatesthatitspenetrationvalueliesbetween80&100.Gradingofbitumenhelpstoassessitssuitabilityindifferentclimaticconditionsandtypesofconstruction.Forbituminousmacadamandpenetrationmacadam,IRCsuggestsbitumengrades30/40,60/70,80/100.Inwarmerregions,lowerpenetrationgradesarepreferredtoavoidsofteningwhereashigherpenetrationgradeslike180/200areusedincolderregionstopreventtheoccurrenceofexcessivebrittleness.Highpenetrationgradeisusedinsprayapplicationworks.

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Worksatveryhelpful...thanksReplyLikeFollowPostJanuary6at6:29am

NirmalaNirmalaFacultyOfEngineeringTechnologyTheOpenUniversityofSriLanka(OUSL)realythisiswonderfulinthatsituationReplyLikeFollowPostDecember29,2014at11:09pm

StephanoBatistaKihaga TakingHighwayEngineeringatArushatechcollegesohelpfulReplyLikeFollowPostNovember5,2014at9:57pm

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EngrNajeebAhmedKhanTareen WorksatPrincipalEngineersandContractorsnicework..ReplyLikeFollowPostSeptember23,2014at1:25am

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MdAmjadAliKhan MNNITnicework,,..especially4"RECOMMENDEDVALUE",,,,,ifpossibleelaboratethissectionmoreReplyLikeFollowPostSeptember1,2014at11:38pm

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