b'S in Energy Comparison traContinued from page 3 help each ofperformASTM D57-95 (l\\lodifiethem toI 4d) lies in the concept ofSTANDARD TESTINGO FORLINGTESTING l\\lODIFIED strainMETH DSSAlllP AND energy.ThinkofstrainB N SHEET l EITUMI OUS\\\'IAT RIAL asl\\lACHINETIOenergynothing more thanCROSSDIREC N the mechanical concept of5P SSYSTEi WERE TESTED0 DEG F SAllI LE PER\\\'IATREES work, which is force timesMRCA 1997 distance.Today,wecanTensileStrainTensileStrain design allofStrength@Strain@E StrengthStrain@E gy kindsdifferentnergy@nerroofmembranesusingMax LoadMax LoadMax Load@ B B @ reakreakBreak asphalt and modifiers alongSpecimen(LB/IN}(%)(IN-LB/IN 2 }(LB (%)(IN B/IN\') /IN)-Lwithdifferenttypesand amountsof glassand/orTAMK0 SYSTEM polyester. Strain energy isAVERAGE197.239.263.9197.239.263.9 the only universal yard stick- . to measure their toughness,GARLANDI PLY 40 PLUS SYSTEM VERSashighstrengthor highAVERAGE3126.96.36.199188.8.131.52 elongationby themselves canbeverymisleading.GARLANDSPLY MINERL STRE~SYSTEM TheircombinedstrengthAVERAGE4 .63.17.2301.43.48.1 20and elongation behavior is key to their physical tough Tamko System ness."1 Ply T LANEM M AMKO AWAP PR IUT following testing was done1 PLY T VERSA SMOOTH heAMKO at Structural R Inc. (S AD WITH T EASPHALT esearch,RI)HEREDYP Ill in Middleton, Wis.II should be noted that the samples were takenGarland Versi-Ply 40 Plus System from one roll of material used in1 PLY G DYPLUS ARLAN VERSI-PL40 these tests. T individual rolls2 P SKO T -PLY heLIE TAM AM IV were tested to assure thatmetADH WITH TYPEASPHALT theyEREDIll published or ASTMcritestrength ria.rollsfrom con Garland Stressply Mineral System Thewere taken tractor inventory.received1 PLYLA STRESSPLMINWhenGAR NDYERAL by SRI, they were incondi 2 P S T KOLY IV goodLIE AM TAM-Ption with packing labels attached.ADH WITH TYPE Ill ASPHALT ERED Physical testing was done on each of the materials, as well asT column that best represents the strain energyis Strain Energy@As can be noted per the heconceptBreak. roof membrane, whichabove testing, the T 20-yearmnearly eight times greaterenergy than eitherthe 30-year syssystems amkosyste hasstrainof were constructedfromtherolltems. materials tested. T membraneToteaticlethe August 1987 issueR.S.I.by Dr. Rene Dupuis, entihequo frommagazine ar inofauthored systems were built with T Illtled, Applying \'Strain Energy\'Test Modified Bitume "Itbe seen that the overallis diffiypeton,canperformance asphalt applied at 400 degreescult to establish if we only study individual material characteristics. By knowing the amount ofstrain usable F renheit.ener asystem has, we are closer to evaluating the overall.strain energy ah gymembraneperformance Usabletells you how much work the material is good for.The effects of weathering, heat, aging,aof moisture andhost mechanical effects can more readily be evaluated." Itldnoted th all three ofse tested systems appearbegood, wh compared to the lo strain shou beatthe toveryenad energy provided by the old standard built-up roof which is three (3) ft/lbs ofT concern is that nothing energy.he in the strain e y test re lts validates themthe 30-year roofs will,fact, perform for 30 years. The~ nerg su clai thatin question raised bytests results is: which system is most likely to experience the longest satisfactory lif these Continued on page 8 4'