Smooth roads are safe roads. Traditional pavements often fail from rutting, stripping, cold cracking, and fatigue cracking, causing damage over time. At Dow, our polymer-modified asphalt offers long-lasting road pavement performance, helping to enable smoother surfaces to prioritize roadway safety across climates.
Roads made with polymer modified asphalt are suitable for heavy transportation loads and can handle more than two times the traffic load1. They are fuel-resistant and offer increased durability by up to 30%2. The benefits are even felt before rubber hits the road. As ELVALOY™ Copolymers for polymer modified asphalt doesn’t need high shear mixing this corresponds to 10% less energy in processing and storing and offers fast application thanks to smooth spreading and easy hand-working.
1Investigation of Low Temperature Cracking in Asphalt Pavements: Cracking in Asphalt Pavements National Pooled Fund Study – Phase II; MnROAD, MnDOT (2010)
2Performance Characterization and Fatigue Damage Prediction of Asphalt Mixtures Containing Polymer Modified Binders and Recycled Plastics
Across the globe roads need to withstand moisture and temperature cycling, especially in freeze-thaw cycles. Asphaltic cement enhanced by ELVALOY™ Reactive Elastomeric Terpolymers (RET) is shown in lab tests to improve pavement service life in these conditions, due to reduced moisture susceptibility causing better asphalt binder adhesion to aggregate.
The U.S. Federal Highway Administration conducted a study to determine the effects of 11 asphalt binders on the moisture sensitivity of mixtures, using a Hamburg Wheel-Tracking Device (Hamburg WTD). The results showed that only the mixture with ELVALOY™ RET performed better than the PG 70-22 control mixture at a 5-percent level of significance.3
On a highway in India side-by-side lane inspection was conducted. Binder made with ELVALOY™ RET asphalt modifier was used alongside an unmodified binder. The side-by-side lanes were observed and photographed years later, showing a visible difference in binder retention—ELVALOY™ RET offering the stronger performance.
3“Understanding the Performance of Modified Asphalt Binders in Mixtures: Evaluation of Moisture Sensitivity” (FHWA-RD-02-029) by Kevin D. Stuart, John S. Youtcheff and Walaa S. Mowager
Cracks happen when temperatures change, and the pavement expands and contracts beyond the binder’s ability to stretch or compress to conform to the movements. Studies have shown that by creating a more resilient binder at a molecular level, ELVALOY™ RET asphalt modifier can minimize cold and thermal cracks.
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 styrene butadiene styrene (SBS) in these tests.
Eleven binders were used in this study of fatigue failure. They included eight polymer modified asphalt binders of PG70-28, using the following polymers: ELVALOY™ RET, SBS linear-grafted, SBS linear, SBS radial-grafted, ethylene vinyl acetate (EVA), EVA grafted, ethylene styrene interpolymer (ESI), and chemically modified crumb rubber. Bending beam fatigue tests were performed according to the AASHTO provisional test method TP8-94 (10). The tests were conducted in the strain-controlled mode at a high strain level of 1000 microstrains and at a test temperature of 19C. 4
Several different data analytical methods were compared, with a consistent result. The mixes made with ELVALOY™ RET far outdistanced the other samples in terms of cycles to failure.
4 “A Distinctive Fatigue Failure Criterion” January 2004, Asphalt Paving Technology: Association of Asphalt Paving Technologists-Proceedings of the Technical Sessions 73:585- 622 by Ghazi Al-Khateeb and Aroon Shenoy.
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