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Washington, DC 20590

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Research and Development (R&D) Project Sites

Project Information
Project ID:   FHWA-PROJ-06-0028
Project Name:   Asphalt Modification with Phosphoric Acid
Project Status:   Completed
Start Date:  December 6, 2006
End Date:  February 20, 2014
Contact Information
Last Name:  Arnold
First Name:  Terry
Telephone:  202-493-3305
E-mail:  terry.arnold@dot.gov
Office:   Office of Infrastructure Research and Development
Team:   Pavement Materials Team [HRDI-10]
Program:   Turner-Fairbank Highway Research Center
Laboratory:   Binder Laboratory
Project detail
Roadmap/Focus area(s):   Infrastructure Research and Technology Strategic Plan and Roadmap
Project Description:   This project continues ongoing research activity that will provide guidance to State agencies and industry partners on the appropriate use of phosphoric acid as an asphalt modifier. Issues still not clearly resolved are the reaction of phosphoric acid with asphalt from different crude sources, reaction with lime and limestone aggregates, and the effect on rutting and fatigue. The comparison of phosphoric acid modification with polymer modification needs to be augmented. There are also unresolved forensic issues in New York State concerning phosphoric acid and premature pavement failures. Until this is resolved, other State agencies will likely reject the use of this potentially cost-saving additive.
Goals:   Material characterization.
Product Type:   Research report
Test Methodology:   Various chemical and spectroscopic techniques, including x-ray fluorescence, ion-exchange chromatography, atomic absorption spectroscopy, and infrared spectroscopy.
Expected Benefits:   The expected benefit is reduced construction costs by using phosphoric acid as an alternative to polymer modification. Currently there is a shortage of Styrene-Butadiene-Styrene for modifying asphalt binders, so there is a dire need to identify modes of asphalt modification that fill this gap. In many circumstances, phosphoric acid modification has this potential.
Deliverables: Name: Guidance on use of polyphosphoric acid as an asphalt modifier.
Product Type(s): Research report
Description: Final report providing best practice guidelines for the use of phosphoric acid to modify asphalt.
FHWA Topics:   Roads and Bridges--Pavement and Materials
TRT Terms:   Asphalt Modification
Phosphoric Acid
Styrene Butadiene Styrene
FHWA Disciplines:   Pavement and Materials
Subject Areas:   Materials


Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101