01363331

Component

http://www.trb.org/Publications/Blurbs/166590.aspx

State agencies in the United States have known for years the benefits associated with asphalt binders that are modified with elastomer-type polymers to improve the rutting and fatigue cracking properties of the hot-mix asphalt (HMA). However, in recent years, many asphalt binder suppliers are now using polyphosphoric acid (PPA) in combination with decreased percentages of polymers to meet various performance grade (PG) asphalt binder requirements. This has raised concerns among the state agencies that fear that the combination of PPA and reduced polymer percentages will result in an inferior asphalt binder when compared to the same asphalt binder solely modified by polymer. To help answer this question, a research program was developed to examine and compare the laboratory properties of an asphalt binder modified with and without PPA. Asphalt binder testing, consisting of PG grading and MSCR (a test developed by FHWA), and mixture testing, consisting of dynamic modulus and flexural beam fatigue tested at both short- and long-term aged conditions, as well as repeated load testing to evaluate permanent deformation were conducted on a base binder and the base binder modified in two manners: SBS polymer only and reduced SBS polymer + PPA. This paper presents the findings of the binder and asphalt mixture evaluation and shows that the use of PPA in formulation with SBS provides an equal performance, with respect to HMA mixture rutting and fatigue performance, to the highly SBS-modified asphalt binder.

01363314

English

pp 70-85

2012-1

Transportation Research Circular

Workshop on Polyphosphoric Acid Modification of Asphalt Binders

Digital/other

Figures; References; Tables

Asphalt mixtures; Bituminous binders; Fatigue cracking; Hot mix asphalt; Laboratory tests; Phosphoric acid; Rutting; Styrene butadiene styrene

Polyphosphoric acid

Highways; Materials; Pavements; I23: Properties of Road Surfaces; I31: Bituminous Binders and Materials

TRIS, TRB

Feb 23 2012 10:18AM

• Analytical Procedures for Determining Phosphorus Content in Asphalt Binders and Impact of Aggregate on Quantitative Recovery of Phosphorus from Asphalt Binders
• Best Practices for Polyphosphoric Acid Modification of Asphalt: Phosphate Forum of the Americas
• Binder Modification with Combination of Polyphosphoric Acid and Styrene-Butadiene-Styrene: National Center for Asphalt Technology Test Track Experience
• Department of Transportation Perspective: A Survey on Polyphosphoric Acid Use and Issues
• Effect of Polyphosphoric Acid on Asphalt Binder Properties
• Establishing a Baseline of Knowledge Through 2005 by Reviewing AI IS-220: Polyphosphoric Acid Modification of Asphalt
• Field Investigation of Polyphosphoric Acid–Modified Binders at MnROAD
• Implementation of Polyphosphoric Acid Modification of Asphalt Binders and Related Experience: Case Study
• Louisiana Approach to Binder Modification
• Modified Asphalt Cement Use in Arkansas
• Polyphosphoric Acid Modification of Asphalt Binders: A Workshop. Workshop Summary
• Polyphosphoric Acid–Modified Asphalt Cement: Ontario Perspective
• Polyphosphoric Acid–Modified Binders and Mixtures: Aggregate and Binder Interactions, Rutting, and Moisture Sensitivity of Mixtures
• Use of Phosphoric Acid as Modifier for Hot-Mix Asphalt
• Why and How of Polyphosphoric Acid Modification: An Industry Perspective
• Wisconsin Approach to Binder Modification