Building Construction Exam 2 With All Answers Correct

BUILDING
CONSTRUCTION EXAM 2
WITH ALL ANSWERS
CORRECT




heatnofnhydrationn-ncorrectnanswer-
exothermicnchemicalnreactionnwhennwaternandnportlandncementncomeninncontact.nth
enhydrationnreactionnbeginsnasnsoonnasnwaternandncementncomeninncontactnwithnea
chnother,nbutnthenratenatnwhichnthenreactionnprogressesnisnextremelynslow.nitntakesn
upnton6nmonthsntonreachnfullnstrength,nbutn80%nofnitsnstrengthndevelopsninn28ndays.
n~2/3nofnthen28-
daynstrengthnisnobtainedninnthenfirstn7ndays,nandn~1/2ninnthenfirstn3ndays.

slumpn-ncorrectnanswer-
thenheightntonwhichnthenconcretensettlesnbelownitsnoriginalnheight:nanmeasurementno
fnsettlementninninchesn-nthendifferencenbetweennthen12-
in.nheightnofnthenconenandnthentopnofnthenslumpednconcrete

water/cementnration-ncorrectnanswer-
thenamountnofnwaternrequirednforncompletenhydrationnisnaboutn40%nofnthenweightnof
nportlandncement.ninnothernwordsnthenw-

, cnrationshouldnben0.40nforncompletenhydration.nexperimentsnhavenindicatednthatnthen
strengthnofnconcretenisninverselynproportionalntonthenw-
cnratio.ntherefore,nanconcretenshouldncontainnthenminimumnamountnofnwaternthatngiv
esnitnthenrequirednworkability

expandednshalen-ncorrectnanswer-
commonlynusednlightweightnaggregate.nobtainednbynheatingncrushednshalentonanhig
hntemperature,nconvertingnanynwaternintonsteam,nwhichn-ninntryingntonexitn-
nexpandsnthenparticle,nreducingnitsndensity.nitsncolornisnsimilarntonthatnofnbrick.


readynmixnconcreten-ncorrectnanswer-
concretenthatnisnmanufacturedninnanfactorynornbatchingnplant,naccordingntonansetnrec
ipe,nandnthenndeliveredntonanworknsite,nbyntrucknmountednin-transitnmixers

advantages:
precisenmix

disadvantages:
90nminutesntongetnontonsite

precastnconcreten-ncorrectnanswer-
concretenmembersntypicallyncastninnanprecastingnplantnandntransportedntonthenconst
ructionnsitenfornerection.nprecastingncannalsonbendonenatnthenconstructionnsite,nsuch
nasnwithnconcretentilt-upnwalls.


dropchuten(elephantntrunk)n-ncorrectnanswer-
cannbenusednifnthenmixerntruckncannbenparkednfairlynclosentonwherenthenconcretenisn
tonbenplaced.nanchutenisnsimplynannopennsteelnchanelnthatnextendsnfromnthendischar
genendnofnthenmixerntonthenconcrete'sndestination.nalmostnallnmixersnhavenanfewnlen
gthsnofnchutenattachedntonit.nanchutentransportsnconcretenbyngravitynandncannonlynb
enusednifnthenconcrete'snfinalndestinationnisnbelownthendischargenendnofnthenmixer

formnreleasingnagentn(formnoil)n-ncorrectnanswer-
beforenconcretenisnplacedninnthenforms,ntheirninteriornsurfacesnarenwithnreleasingnag
entsntonallownthenformsntonbenstrippednwithoutndamagentonbothnthenformsnandnthenc
oncrete.ntheynlubricatenthensurfaces,nandninnthencasenofnwoodnandnplywoodnforms,n
sealnthensurfacesnagainstnwaternabsorption,nwhichnincreasesnformnlife.ntheynareneith
ernoilnornwaxnbasedncoatings.

WWFn(mesh)n-ncorrectnanswer-
prefabricatednreinforcingnsteelnavailableninnrollsnornmats.ntheynarencommonlynusedni
nnground-supportednslabsn(ornpavement)nandnsteelndeck-
supportednslabs,nwherenreinforcementnrequirementsnarenmarginal,nthatnis,nmuchnsm
allernthannthosenneedednfornreinforcednconcretensuspendednslabs.nthenusenofnWWF
ngreatlynspeedsnupnthenreinforcementnassemblynlinenonnsite


prestressingn-ncorrectnanswer-
introducingncompressionntonregionsnofnthenmembernthatnarenexpectedntonexperience
ntensionnasnanresultnofnthenloads.nthencompressionnisncontrollednsonthatnitneithernred
ucesnorncancelsnthentensionncreatednbynthenloads.nprestressingnisnobtainednbynusin