FRITZ ENGINEERING LABORATORY LEHIGH UNIVERSITY

1 , :IILEHIGHUNIVERSITYBETHLEHEM, ' '__'5 '.' ' :13 AbrasionTests19"TestforToughness;.','19 HardnessTests"'20. 'CoefficientofExpansionTests>-:21-MeanRe sultsofPhysicalTests<:23-TeststoDetermin etheTemperatureatwhichCracksDevelop24_Te ststoDeterminetheDistancebetweenaHeating UnitandSpecimen,-theTemperatureandPeriod ofTimetoDevelopCracks:;,27 MeanResultsofTemperatureTests27' ~.~~ "82 -SpecificGravityTcsts,..~9'3 -FlexureTests-DimensionsofBeams147 -FlcxureTests~Scries13':158-FlexureTests -SeriesC;159 "2012-Coefficient'ofExpansionTests2313an d13(a) ~cksDevelop24-2514-TesttoDetermine'Dista nce,TemperatureandTime2715-OhmicResistan cepercubicinch2916-OhmicI~esistancebetwe enmetalpoints3017-OhmicResistan'cepercub ic"i~ch(oncubes)31,'/,,-, (a) (ll) ::7 TypicalCompressionFractures12 TypicalFracturesofSlateBeams':~17 TypicalFracturesDuetoHeat26".

2 --1 PHYSICALANDELECTRICALTESTSOFSLATEINTRODU CTIONT hemainobjec"tsofthetestshereinreportedwe retodeterminethephysicalpropertiesofa so-calledelectricalslateanditsspecialsui tabilityfQruseintheelectricalindustries" Thespecimenswerefreefromribbons,hada fine,evengrain,densecompactstructure,' "jorityofthetestingwork"wasperforIl]edin theFritzEngineeringLab-"oratory,LehighUn iversity,amithespesimenswerefurnishedbyt heStructuralSlat~ , , , ,totheCivilEngineeringDepartmentofLafaye tteCollegefortheuseoftheirAbrasionmachin e,andtotheStateHighwayDepartmentwhosokin dlyallowedtheuseoftheirmachinesfortheHar dnessandTo' ,uniformstructureofthematerial,whichi ,curiously,enoughalmot identicalinappearancewiththetructureofa :'HOTOMICROGRAPHOFSLATE325 DIAMETERSPHYSICALANDELECTRICALTESTSOFSLA TEPHOTOMICROGRAPHSOFSLATE200 DIAMETERS78 PHYSICALANDELECTRICALTESTSOFSLATEQUANTIT ATIVECHEMICALANALYSIS\'Thespecimensusedi nthisdeterminationwereaveragesamplestake nfromthebrokencompressionspecill~ ,onequarterdiscarded,thebalancewasthenmi xed finalquarterre-tainedforfi!

3 L1egrindinginanagatemortar,inordertosecu rea repre-sentativesample' ,givestheresults:.TABLE' 'Silica_---------------(Si02) ;10 Alumina(AI203) ;10 FerricOxide(Fe203) ; (FeO) ;10 Lime-:-(CaO) ;10 Magnesia(MgO)~ ;10 Soda(Na20) ;10 Potassa~__(K20) ;10 CarbonDioxide---(C02).. ;10 Pyrite(FeS2) ;10 Waterbelow110 ;10 Carbon~(C) ;10 Amicroscopicexaminationofthesampleofthea boveslatewasmadetodeteni, , ~ , crysta11ineap-pearanceunder'themi'cros ,suchascalciumcarbonate, ,thechiefmineralcontentsofslatewereinthe orderoftheirabundance;a verycomplexsilicate(muscovite),a "cubes:Theweighingwasdoneona ' ' \ \ '. , \V= 'vV'=\ "x8"X1". ,theywerecarefullyweighedandthenimmersed inwaterfor24hours, towel, ,dividedbythefirstweight, , ~-~ \ "IImmersionIWeightsDryIIgramsgralTISI gramsWeightIIII-~ ,andduetothefactthatbuildingsJoneisnotal lowedtotakeanytension, "longby2"widebyI"thick,thecentersectionb eingcutdownfora distanceof2" " (a) RiehleTestingmachine,theloadappliedbymea nsofthemovableheadofthemachineata (b)wasrunasa (a)lof3"-I1}-I'FIGURE1(b) ' # ' , , ' # ".

4 ,1112 PHYSICALANDELECTRICALTESTSOFSLATECOMPRES SIO~TESTSC ompressiontestsweremadeon2"cubescutfromt heclear~ "sphericalbearing-blockusedtocYcnl~' "x2"x2"givinga , , " " , ~ , ,15029,90050,33037,44050, ,20035,13042,80044, ,8928, ,7608, !--------H----f-----+ , , , "erage10,250# ,\PHSHO\\'INGSEVERALTYPICALCOMPRESSIONFR ACTURESOF2" ' ,wereofthin)4"( "wideand26" ,were0"(approx.)thick,I"wideand26" ,wereI"(approx.)thick,I"wideand26" ,were10"thick,111"wideand26" ,eweretestedasbeamsonwooden:supports24" RiehleTestingmachinetothespecimen,andthe deflectionsmeasuredbymeansofanAmesDialre adingto1/1000ofaninch, ,noattemptwas'madetorecordtbeloadcausing failure,butrathertoobtaintheamountofdefl ection' ". ", ", ", , ", ", ", ", , ", ".Series13,CandDweretestedthesameasSerie sA, SeriesB, , , > \tSeriesASeriesC1\IIIIIIII\ ~ ~'e' \IIIII~. }zI2I" ) \ \ \ \ \ \ \SeriesBll~SeriesD\I\I\ \14\.

5 \.15" ""\ \ "I20\\ "I\ "23\\ \\ \I28I1 ,SERIESBR esultsofBeamTestson0"xI"x,?6"SlateBeams. ~Depth0".Spa'n24". , )70 ILoadI, # ' , ~~ , , ,SERIESCR esultsofBeamTestsonI"xI'"x26" ".Span24".Loadatmidd' 'Max.\ ' ' "j# # ,I' ,,. ,230, ,120, ,550, ~;= ,940, ,940, ,740, ,500,000I35IO' ,270, ). ,880, ,200, ,437, #=9,600,000# ,SERIESDR esultsofBeamTestsonI"x10"x26" ".Span24". #. # ,6006,700, ,2007,169, ,2007,998, ,4007,998, ,2007,998, ,1007,998, ,950'7,998, ,1009,140, ,9507,998, ,998, ,1007,998, ,9507,998, ,745I7,912, [. ' \. \. '.0623.!-1 _06_8----'5, '..-1_ ! !..\_--''-__.'-_EfromcompositecurveatLoa d500.#=8,050,000# ;Spec.\. \500I550'1600I650I700#I IIII'IIII\I10\. '\. ' ~3\. \. '. '.061I ----I___.:630II ".'"""""" ''!;."-.:i"Ii:-~.._'. -:"..~.~, ..~,'"",'z"'"-:'._.,PHOTOGRAPHSSHOW[:\,G SEYER.\LTYPIC\LFR.\CTI.]]

6 :RE~ ~[SOF0" ~ISOF1" " ~()~o~O( $0~~..5 f~.4~(l.~~" ..4~.?~'1-. 0,\~30(:;'\)~2So2~o/50I(J~~of}0 PHYSICALANDELECTRICALTESTSOFSLATECUI'J' 'e4 LOdd-PI?/Ie>c17o17 SLRT ,50")( ''$,P""/.~" )e"/7'1'Jlrt'rt~f'1' ,~c/~e,/J'.01-.()Z:( '-; ~. 'QrRrP~//ec//o/7//7i/7C//RS,PHYSICALANDE LECTRICALTESTS'OFSLATEABRASIONTESTST hesamples ,asnearlyaspossible, \ (1/16") " :Weightbeforetest-:~ ~ ~10,002 RevolutionsperMinute__= ,asapplied-torock,istheresistancetofract ureunderimpact,expressedasthefinalheight ofblo\vofastandardhammertocause' cast-ironanvilandahammerweighing2kilogra msarrangedsoastofallfreelybetweensuitabl eguides,ahardenedsteelplungerarrangedto slidefreely,thelowerendoftheplungerbeing sphericalinshapewitha ~ , ,a 2centimeterfallforthesecondblow,andaninc reaseof1-cen-timeterfallforeachsucceedin gblowunti'lfailureofthespecimenoccur?.)) )]

7 120 PHYSICALANDELECTlnCALTESTSOFSLATEHARDNES STESTT hetestforhardnesswasmadeonaDarrymachine, consistingofarevolvirigdiskonwhichisfed, atauniformrate,astandardquartzsandpassin ga 30-andretainedona 40-meshsie~ ,cutwithadiamonddrill,each25millimetersi ndiameterand50millimetersin,--,heightwit hfacesgroundoffsoastobeatrightanglestoth eIDngaxis, ' :Hardness=20-%VV, ;tIweig~tbefore\Weightafter1000\ \ 'inthedeterminationoftheCoefficientof,Ex -pansionTestswere274" "x8".Oneinchfromeachendofthespecimenando nthecenter-lineofoneofthe274"x 8"faces,holes%" ,thepointsextendingapproximately%" , ,theheatingcoil~beinglocatedinthebottoma ndwallsofthefurnace,andismadetooperateat 250volts, ,atamaximumtem-peratureof1850 F.,andasafeworkingtemperatureof1750 " :11peraturedeveloped:TheinS'idedimension softhebodyofthefurnacemeasure4"x3"x12".T hecover,madeofa porous,heat-insulatingmaterial,isprovide dwithtwoopenings8"long,onefortheadniissi onoflightandth~ , ,apairofbrackets,supportingtwoverticalpo sts, ~istsofastationaryverticalcross-hait:, \ circularmicrometerscaleonthethumb-screw, ".

8 Thecircularmicrometerscaleisdividedintoo nehundredequalpartsthusallowinganactualr eading, " ".Afterthestation-aryverticalcross-hairs havebeenadjustedtotheneedle-pointsonthes pecimen, !~"22 PHYSICALANDELECTRICALTESTSOFSLATEP rovisionismadetoinsertathermo-couplethro ugha smallholeintheendofthe,furnace;Inthispar ticulartest,however,a Centigrade' "itwasplacedontwosupportsinthefurnacebot tom,oneroundandtheothersquare,soplacedas toinsureasfaraspossible,anexpaI}sionatbo thendsandalsotodecreasetoa ~theplacingofthe'specimen,atthebe-ginnin gofeachtest,a ,onewasplacedinthefurnace,thedistancebet weenneedle-pointsmeasured,thetelescopesa dj' ,and,aftera shorttime,toallowtheheattohaveanopportun ityof"soaking"intbthespecimen,securingth erebyanequaldistributionofheatthroughout thefurnaceandspeci~men"readingsweretaken atvariouste:l1peraturesuptothemaximU'll' ,thetestswerenotcarriedabove' ) ,andinthethirdal11dfourthtestsbetter,res ultswereobtained,andstillfurtherimprovem entwasmadeafterthesetwo,tests, , 'lythesame,showsthatthetestswereverysati sfactory.

9 ' ' ~"","", , ~.IIinchesI CI CI CIinchesdegreeCIIIIIIIII- IIII! ' , ' ' 'OFPHYSICALTESTST hefollowingisa recapitulationofthemeanresultsofthephysi -caltests:SpecificGravity-~ ,625# :.10,250"" 'i" "" "depth7,940"" 'i"depth10,250"" "depth9,600, " 'lasticityof23-'i"depth8,050,000"" ,, , ~_~ ' :\TETESTTOm:<:TERMINETHETEMPERATUREAT\ ;.-OPThespecimensusedinthistestwere2"x2" x8".Thespecimenswereplacedina MultipleUnitElectricFurnace,Type87,witha maxi-mumtemperatureallowableof1850 F., F.,250volts, C.' ! 'otherthreespecimensweresubjectedtoagrad uallyrisingtemperatureuntilafixedtemper- -aturewasreachedandthel'! ,itwillbenotedthatthereisconsider-ableva riationinthetitherequiredtodevelopcracks , to5 inclusiveisabout330 ,balanceofthespecimens, ,'7and8, (a),itwillbenoted periodof24minutes, ,roseonly40 ,5hoursand10minuteswithoutanysignofa ,and30minutesmore,or5hoursand40minutesfr omthestartofthetest,cracksdeveloped.

10 " CI350 CI321 \l\ \ C\360 C330 C\ CI360 CII330 CIII19n11n.)Fu:~~'t~ta~'~;l~when4I23925 CI370 C335 C375 C\ 349 C46111111.\Fumace200 '\Furnace275 ( :ISpecimencracked_Crack-=.ed-= , Cwhe~teststarted_II,Crack~ (a)Testtodeterminethetemperatureatwhichc racksdevelop.! !RoomIPyrom.\'Diff'ITim~ +------f----------------c-I:~-+I-I--I1II 6I239126 CI230 C204 CIO' CwhenI 1II240 C-I214 I2"Iteststarted_IIII250 CI224 CI4"IIII260 CI234 CI11 IIII270 CI244 CI14"IIII280 CI254 CI20"II239126 CI290 C264 CI24"I7I239126 CI230 Cr204 CI2 WCI1"IIII250 CI224 CI2"1II260 CI234 CI3 IIII270 C244 C9"II1-I275 C249 CI12 IIII260 C-234 .CI17 IIII260 C234 C22"IIII270 C244 CI27II239126 CI270 C244 C29I8I239125 CI275 C\ 250 C\ CI240 CI10"IIII260 CI235 CI20"IIII270 CI245 CI30"II1I270 CI245 CI40"I-III260 C1235 CI50-"IIII260 CI235 CI60"IIII270 CI245 CI70"IIII280 CI255"CI80"IIII270 C245 CI90"IIII260 CI235 C100"IIII280 CI25'SoC110"IiII290 CI265~CI120"IIII280 CI255 CI130"IIII280 C255 C140"IIII280 CI255 CIISO.