ASTM Standard		50 Duro	60 Duro	70 Duro
Physical Properties
D 2240	Hardness	50 ± 5	60 ± 5	70 ± 5
D 412	Tensile strength, psi	2,250	2,250	2,250
	Ultimate elongation, minimum %	450	400	300
Heat Resistance
D 573 70 hour at 158°F	Change in durometer hardness, maximum points	+10	+10	+10
	Change in tensile strength, maximum %	-25	-25	-25
	Change in ultimate elongation, maximum %	-25	-25	-25
Compression Set
D 395 Method B	22 hours @ 158°F maximum %	25	25	25
Ozone
D 1149	25 pphm ozone in air by volume, 20% strain 100°F ± 2°F 48 hours mounting procedure D 518, Procedure A	No Cracks	No Cracks	No Cracks
Adhesion
D 429 B	Bond made during vulcanization, pounds per inch	40	40	40
Low Temperature Test
D 2137	Brittleness at –40°F	No Failure	No Failure	No Failure

NOTE: Certain states specify requirements other than standard AASHTO specifications. When ordering, identify all requirements or submit individual state specifications.

Above meet Standard Specifications for Highway Bridges, adopted by the American Association of State Highway & Transportation Officials, Sixteenth Edition, Section 251-92 Level 1 – Elastomeric Bearings.