Bending Beam Tests Demonstrate Cold-Temperature Performance

The cracking temperatures for asphalt binders provided by the Bending Beam Rheometer (BBR) and Thermal Stress Analysis Routine (TSARTM) were studied by the U.S. Federal Highway Administration (FHWA Report RD 02 075). Low-temperature mixture properties provided by the Thermal Stress Restrained Specimen Test (TSRST) were used to validate these asphalt binder tests. An emphasis was placed on evaluating the performances of mixtures containing polymer-modified asphalt binders with identical Superpave performance grades (PG's) and similar base asphalts, but varied modification chemistries. Elvaloy® RET broadly outperformed grafted SBS these tests, in granite and limestone aggregates tested.

Aspalt Mixture designation TSRST Fracture temp.

 

Test #1 Test #2 Test #3
 

STOA = 2 h

ESI -32.7 -31.9 -33.2
Elvaloy® -31.3 -35.4 -34.3
SBS Linear Grafted -29.6 -34.0 -35.5
EVA Grafted -31.1 -25.8 -36.3
SBS Linear -32.2 -30.1 -29.1
SBS Radial Grafted -31.3 -26.1 -33.0
EVA -29.6 -29.0 -30.4
CMCRA -28.6 -29.7 -28.4
Air-Blown -26.3 -27.8 -27.3