道路工程材料申爱琴版作业集料水泥英文版.docx

道路工程材料申爱琴版作业集料水泥英文版.docx

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道路工程材料申爱琴版作业集料水泥英文版

AssignmentforRoadEngineeringMaterials

Chapter1&Chapter2

Name：

Class：

NO.：

SCHOOLOFHIGHWAYCOLLEGE

CHANG’ANUNIVERSITY

OCTOBER31,2013

ChapteroneAggregate

1.Herearetwokindsofstone,andthetestresultsareshowninfollowingtable.Whichkindofstonehasbetterperformance?

Solution:

Step1,theporosityofthesetwostonecanbecalculatedasthefollowingformula:

Andthe

.

Step2,thevaluesaturation-watercoefficientofAstoneis0.75,whichishigherthantheBstone’s,0.65.

Step3,thehigherporosityofstoneis,thebetterwaterabsorptiongetsandtheworsefrostresistanceis.Soisthesaturation-watercoefficient.Fromwhathasbeenmentionedabove,thestoneAapparentlygetsahigherporosityofstoneandsaturation-watercoefficient,sothestoneAisworseatfrostresistance.

Conclusion:

stoneBhasbetterperformance.

2.Pleasedescribethedifferencebetweenstrengthindexesofstoneandaggregate,andthetestmethods.

Solution:

a）Themajorstrengthindexforstoneisuniaxialcompressivestrength.Theresultofmeasuringuniaxialcompressivestrengthtestisrepresentedasresilientmodulus

withtriaxialchamberwithexternalLVDT’sandloadcell.Andthepreparesamplecanbecube（inroadengineering）orcylinder（inbridgeengineering）.

b）Themajorstrengthindexforaggregateiscrushingvalue.Andthetestmethodisinthebelow.

ProceduretodetermineAggregateCrushingValue

i）Theaggregatespassingthrough12.5mmandretainedon10mmISSieveareoven-driedatatemperatureof100to110oCfor3to4hrs.

ii）Thecylinderoftheapparatusisfilledin3layers,eachlayertampedwith25strokesofatampingrod.

iii）Theweightofaggregatesismeasured（Weight‘A’）.

iv）Thesurfaceoftheaggregatesisthenleveledandtheplungerinserted.Theapparatusisthenplacedinthecompressiontestingmachineandloadedatauniformratesoastoachieve40tloadin10minutes.Afterthis,theloadisreleased.

v）Thesampleisthensievedthrougha2.36mmISSieveandthefractionpassingthroughthesieveisweighed（Weight‘B’）.

vi）Twotestsshouldbeconducted.

Aggregatecrushingvalue=（B/A）x100%.

3.Pleasedescribetheclassificationofaggregatefromdeferentperspectives

Solution：

Solution:

Notification:

Thereissomeothertypesofaggregatebydifferentstandards

●Crashedgravel

●Crushedsand

●Stonechip

●Filler

●Slag

4.Therearetwokindsofaggregate,andthetestresultsareshowninfollowingtable.Pleasedescribethedifferenceoftheperformanceofthesetwokindsofaggregate.

Solution:

Thelowercrushingvalueis,thebetteranti-crushingperformanceaggregategets.AndsoistheLosAngelesabrasionration.So,theaggregateBhasabetteranti-crushingandanti-crushingandabrasivenessperformance.

Thehigherpolishingvalueis,thebetteranti-slipperformanceaggregategets.So,theaggregateAhasabetteranti-slipperformance.

5.Pleasedescribethedefinition,thetestandthecalculationmethodsofdensitiesofaggregate,andgivetherankofdifferentdensities.

Solution:

a）Truedensity:

Definition:

themassofaunitvolumeoftheimpermeableportionofmaterial,includingthesolidandimpermeablepore..

Test:

LeChatelierflaskmethod

Calculationmethod:

b）Apparentdensity:

Definition:

themassofaunitvolumeoftheimpermeableportionofmaterial,includingthesolidandimpermeablepore.

Test:

Wirebasketmethods

Calculationmethod:

c）Bulkdensity:

Definition:

themassofaunitvolumeofmaterialundernaturalstatus,includingsolid,permeableandimpermeablepores.

Test:

Wirebasketmethodsforcoarseaggregate

Flaskmethodforfineaggregate

Calculationmethod:

d）Stackingdensity：

Definition:

drymassperunitvolumeofaggregateundersomestackingmethods.

including：

Loosedensity,Tampingdensity,Compactiondensity

Calculationmethod:

Rank:

6.

ThegradationcurvesofthreekindsofaggregateareshowinrightFig.Pleasejudgethegradationcategories,andthestructureofasphaltmixtureconsistedoftheseaggregate

Solution:

GradationAisthegapgradation.Oneormoreintermediateparticlesizesaggregatesaremissing.

GradationBisthecontinuousgradation.Theparticlesdistributeoneachsievesizefromthelargetosmall.

GradationCistheopengradation.Theparticlesdistributeonlargersievesize.

7.DiscussthedifferencesbetweengradationandfinenessmodulusoffineaggregateHavesandAandsandB,whichhavethesamefinenessmodulus,thesamegradation?

Solution:

Gradation,theparticlesizesandsizedistribution,referstotheproportionbymassorweightofaggregateparticlesdistributedinspecialparticle-sizeranges,notonlytoindividualfineandcoarseaggregate,butalsotothecombinedormixedaggregate

Finenessmodulus,avaluewhichstatisticallyrepresentsthecoarseorfineconditionoffineaggregate,isstatisticallydeterminedbythepercentageofcoarseaggregate

So,thedifferentgradationcanhavethesamefinemodulus,andthesamefinemodulusmaynotrepresentthesamegradation.

SandAandsandBcanhavethesamethesamefinenessmodulusbutnotthesamegradation.

8.Sievingtestresultsof500gsandareshownintable.Pleasefilltheblank,andcalculatethefinenessmodulus.

Solution:

sievesize（mm）

9.5

4.75

2.36

1.18

0.6

0.3

0.15

Pan

mi（g）

0

20

15

40

115

125

155

30

ai（g）

0

4

3

8

23

25

31

6

Ai（g）

0

4

7

15

38

63

94

100

Pi（g）

100

96

93

85

62

37

6

0

Thefinenessmodulus:

2.052

9.ThepassingpercentagesoffouraggregatesarelistedintheTab.9.1andthegradationlimitareshowninTab.9.2.Pleaseusethegraphicmethodandlinearprogrammingmethodtodeterminetheproportionsinmixedaggregateaccordingtothemid-valueofgradationlimits,andcalculatethecompositegradation.

Table9.1

Table9.2

Solution:

Linearprogrammingmethod

ThegradationcanbedesignedbytheExcelmacro,linearprogramming,aslongassomeconstraintsarecorrectlyset.

Hereisthegradationdesignsheet.

Designedvaluesofgradationarethenumberswiththebluebackground.Theyareproportionsofdifferentcomponentswhicharesimulatedbylinearprogramming.

Withtheassumedamountoffouraggregates,thecompositevaluescanbecalculatedandtheyaredisplayedinthesheet.

Andnextisthegradationcurve

Therearefourlinesinthisillustration.Fromthelegend,itcanbeknownthatthepurpleone,compositegradation,isalwaysbetweentheupperlimitofgradationandlowerlimitofgradationandapproachingthemiddlevalueofgradation.So,thedesignofcompositiongradationisqualified.

Graphicmethod：

Thegradationisillustratedintheattachedgraph.

10.Theshapeandsurfacetextureofaggregateparticlesareimportantforbothcementconcreteandhotmixasphalt.

（1）ForpreparingPCC,wouldyoupreferroundandsmoothaggregateorroughandangularaggregate?

Brieflyexplainwhy.

（2）ForpreparingHMA,wouldyoupreferroundandsmoothaggregateorroughandangularaggregate?

Brieflyexplainwhy.

Solution:

（1）ForPCC,theroundandsmoothaggregateparticlesaredesirabletoimproveworkability.Becausetheangularaggregatewillbemoredifficulttoworkinplaceandeasiertobefractured.Besides,aggregatewitharoughtexturearemoredifficulttocompactintoadenseconfigurationthansmoothaggregate.

（2）Forasphaltmixture,angularandroughaggregateParticlesaredesirabletoimproveworkability.Becauseangularaggregateproducebulkmaterialswithhigherstabilitythanroundaggregateandtheroughnessofaggregatesurfaceplaysanimportantroleinthewayofaggregatecompactsandbondswithbindermaterials.

11.Asampleofcoarseaggregatefromastockpilehasthefollowingproperties:

Massofwetaggregate=5298g

Massofovendryaggregate=5216g

Massofaggregateinwater=3295g

MassofSSDaggregate=5227

Determine:

（a）Thebulk&apparentspecificdensity

（b）Themoisturecontentandabsorptionofstockpileaggregate

Solution：

Known:

a）Theapparentspecificdensity

Thebulkspecificdensity

b）Theabsorptioncontent

0.21%

Themoisturecontent

1.57%

ChaptertwoPortlandCement

1.Brieflydescribethehardeningprocessoflime.

Solution:

Thehardeningprocessoflimecomprisestwoparts,recrystallizationandcarbonification.

Part1:

Recrystallization

Thereactionproducthassomestrengthbythecrystalandshowssomecementingproperties.

Part2:

Carbonification

Thereactionproductisinsoluble,showingbetterwaterstability.Anditmakesmaterialdenserandhigherstrength.

2.Discussthereasonofthegenerationofunder-burntlimeandover-burntlime.Explaintheharmsofover-burntlimetoconcretestructure,andhowtoeliminatetheharm.

Solution:

a）Under-burntlime

Generationreason:

Whenfireheatinlimekilnisnotevenorrawmaterialsizeisoverlarge,someproductmaybecome“under-burntlime”whichisconsideredasresidue.Itwillreduceactualcontentofactiveingredient.

b）Over-burntlime

Generationreason:

Iffiringprocessisoverheatorovertime,someproductmaybecome“burnedlime”.

Harms:

Becausesomeexpansionfrom“burnedlime”involumewillstilltakeplaceduringapplicationprocessandinservicestage,itwillresultincrackingandplasterflaking.

Elimination:

Immersingtheburntlimeintheslakingpoolforseveralweekssothatthoseunslakedgraincangettotallyslaked.（陈伏）

3.WhatingredientsareusedfortheproductionofPortlandcement?

Whatistheroleofgypsum？

Solution:

ProductionofPortlandcementstartswithtwobasicrawingredients:

acalcareousmaterialandanargillaceousmaterial.

Thecalcareou