Glass - Building Material

1. Definition
2. Manufacturing Process
3. Properties
4. Type of glass
5. Uses

1. GLASS
(building material)
GEETIKA SINGLA

2. DEFINITION
•ThetermGlasssignifiesanamorphoussolidsubstance
thathasbeenformedbysupercooling;aliquidsolution
containingchieflysilicaandsomeotherselected
components.
•InGeneralusageglassesaredefinedassupercooled
liquid.

3. MANUFACTURING
•Thebasicrawmaterialforthemanufacturingofgood
qualityglassissilica,whichinnatureoccursasquartz(
SiO2),thematerialmeltsat17000Candiscooledrapidly
withoutallowingIttoundergorecrystallization.
•Quartzandotherdesiredcomponentsareheatedin
specialmeltingfurnace.Themoltenglasscomesout,
ratherflows,fromthesefurnacescontinuously.Various
Glassshapesareobtainedfromthismoltenglassbyone
ofthefollowingprocess.

5. PRESSING
BLOWING
DRAWING
Airisblowninacontrolledmanner
throughthemoltenglassinproper
containers.Thisairpressuredragsthe
glassliquidtoadesiredshape.
Mouldsoftherequiredshapesarefilled
withthemoltenglass.Itisthencooled
whileunderdesiredpressure.Sheetsof
glassaremadebythismethod.
Inthisprocess,streamofmoltenglass
ismadetopassthroughthemolten
rolls.Itcomesoutfromtheotherside
inthedesireddrawnfromoncooling.
MANUFACTURING PROCESS

7. PROPERTIES
•Glasshasquitehightensilestrength.Inveryfinewiresdrawnfrommeltsglass
mayshowtensilestrengthashighas7.0x105kg/cm2.
•Theordinaryglassthreadpossesstensilestrengthof700to1400kg/cm2
•Themodulusofelasticityofglassisalsoveryhigh.Boththeseproperties.
Howevershowgreatvariationdependinguponthecompositionoftheglassand
methodofmanufacturing.
•Glasseshavelowductility,lowconductivityandlowcoefficientofthermal
expansion.
•Glassesareresistanttoacidsandmanyotherchemicalshencetheyareideal
materialforstorageofchemicals.
•GlassesareverygoodelectricalInsulators
•Theyhaveveryhighsofteningpointandcanbeusedathightemperature.

8. Manyvarietiesofglassaremadebyaddingspecialcompoundsin
thesilicondioxideatthetimeoffusion.Followingaresome
commonlyusedtypesofcommercialGlass
SilicaGlass
•ItispureSilicaSiO2,withoutanyadditives.Itsuseisrestrictedto
hightemperatureapplications.Ithasahighsoftening
temperature.
SodaLimeGlass
•Thisisthemostcommontypeofglassusedextensivelyfor
domesticpurpose;windowpanes,plateGlass,LightBulb,and
Containers.ItiscomposedofSiO2,Na2O,CaO.
TYPES OF GLASS

9. LeadedGlass
ThisglasshasahighreflectiveIndex.ThispropertyisInducedintothe
GlassbyaddingleadOxidewithSilicaduringthemanufacturingStage.A
usualCompositionofleadglassisSiO2,PbO,K2O,Na2O.
ThisLeadglasshasspecialapplicationsuchas;
•InMakingshieldsforprotectionagainstgammaradiations.
•InthemanufacturingofopticalInstruments•ForMakingNeonSigns.
TYPES OF GLASS

10. BorosilicateGlass(Pyrex)
•ItisspecialtypeofglassmadebyaddingBoronOxideasthechiefadditive
withSilicaatthetimeofManufacturing.Thispropertyofboronoxidegivesthe
specialpropertyofincreasingitsmeltingpointandresistanceagainstthermal
shock.ThisGlasscanbeheatedorcooledagain&againwithoutanyriskof
damage.Thisisbecausethecoefficientofexpansiongetsreducedconsiderably
bytheadditionofboronOxide
•BorosilicateGlassisusedextensivelyinhightemperatureconditionssuchas;
•MakingofLaboratorywaresforexperiments;
•CookingUtensils
•ItisalsousedfortelescopeandGlasspiping.
•PyrexisthetradenameforBorosilicate.
TYPES OF GLASS

11. Glassusedinindustryinvarietyofforms,somecommonforms
areasfollows;
PressedGlass
•Thisispreparedbymoldingthefusedglassintosheetsandother
shapesunderpressure.Thesesheetsarestartingmaterialfor
makingGlasswaresandStructuralBlocks.
GlassBuildingBlocks
•Thesearemanufacturedfrompressedglassbyfusingtwoor
moresheetsinsuchawaythatpartialvacuumiscausedinthe
interioroftheblocks.Theseblocksareusedinmasonry
constructionforpermittingtransmissionofLightwithoutbeing
transparentandwithoutbearinganyload.
INDUSTRIAL FORMS OF GLASS

12. INDUSTRIAL FORMS OF GLASS
GlassFibres
•IthasbeenfoundthatverythinfibresofGlasspossessveryhigh
tensilestrength.Thethinnerthefibrethehigherthestrength.This
propertyhasresultedinaseparateindustryofconsiderable
importancetheglassfibreindustryfibreofglassaremadeina
specialmannerthemoltenglassisforcedoutthroughnumerous
minuteopeningsintheformofthinstreamsuponthesestreamis
impingedablastofairorstreamunderapre-calculatedpressure.
Thestreamsolidifiesintothinfibres.TheGlass-reinforcedplasticis
commonlyknownasFIBREGLASSandhasacquiredaplaceofits
ownasacompositeengineeringMaterial.

13. LaminatedGlass
•Thesearemadebyboundingtogethertwoormoreplatesof
glass.Sometimes,layerofathirdmateriallikeasphalt,rubberor
resinarealsomadeapartofthelaminatedglass.
LaminatedGlasscanbecharacterizedas:
•ShatteringResistance
•Itspiecesdonotflyawayinallthedirectiononitbroken
suddenlyunderimpact.ThismakesthelaminatedGlassanideal
materialforuseasasafetyglassinautomobileandaircraft.
•ShockResistance
•Itcanbearsafelysuddenimpactsuptodesiredvalue.This
propertyalsoplaysinlaminatedglassbeingUsedasasafety
Glass.
INDUSTRIAL FORMS OF GLASS

14. INDUSTRIAL FORMS OF GLASS
BulletResistantGlass
•Thisisspeciallyusefulinvehiclesandother
automobilesusedforsecurityreasons.Itisinfacta
varietyoflaminatedglasswhichismadebypressingto-
geatherseverallayersofglassandvinylresinsin
alternatemanner.ThicknessofsuchGlassvariesfrom
12mmto75mmormore.

15. USES OF GLASS
GlasshasaverywidefieldofIndustrialApplications;
ForanArchitect;
•Glassisanindispensiblearchitecturalmaterial.In
allthemodernbuildingincludingthehigh-rise
buildings,Glasscurtainwallsmaketheskyline.

16. USES OF GLASS
ForanCivilEngineer;
•Itisoneofthemostimportantmaterialfor
constructionwhichcannotbeavoided.
ForAnElectricalEngineer;
•Glassisausefulinsulatingmaterialinmany
situations,andisalsoanessentialmaterialfor
makingtubesandvalves.

17. USES OF GLASS
ForaMechanicalEngineer;
•Glassaloneorinacompositematerialisanintegralpartin
automobilesandotherlocomotivesincludingrailwaywagons
ToaChemicalEngineer;
•Itispackagingmaterialwithoutanyeasyalternative.
•Glassfindsitsapplicationfromthekitchenofpoormanto
mostadvancedscientificdevicesandinpalatialbuildingand
CabinetRooms.Itcanbemadeinvarietiespossessinga
combinationofmechanical,electrical,optical,andchemical
resistantpropertiesthatmakethemidealindustrialMaterial
forvarietyofApplications.