Asphalt Release Agents (ARA)

Asphalt Release Agents are chemical products developed and manufactured as alternatives to diesel and solvents commonly used for cleaning equipment associated with Hot Mix Asphaltic Concrete (HMAC) production and placement on government and private facilities. The United States Oil Pollution Act of 1980 was used as the foundation to build the current program. The intent of asphalt release agents is to eliminate harmful stripping products that come into contact with bituminous products and strip the asphalt (binding agent) from the aggregates causing potholes, raveling, and other detrimental pavement failures.

True ARAs are biodegradable and do not pose a health risk to workers or an impact on the environment. When used properly, they provide a barrier to the bituminous mixes and allow for very little cleanup of the equipment at the end of the day. The testing within this Committee’s Work Plan attempts to limit the reapplication needs of the ARAs, thereby increasing the cost-effectiveness of these products to make them more viable in lieu of diesel and solvents. This Technical Committee’s charge is to create a uniform testing protocol that will allow individual State DOTs to use the data as specified to formulate their own Quality or Material Producer List (QPL or MPL) in an attempt to reduce duplicative testing and workload within each State.

The NTPEP Technical Committee responsible for authoring the project Work Plan convenes annually at the NTPEP National Meeting. During this working meeting, the Project Work Plan is discussed, changes made, and shortly thereafter balloted for adoption. Improvements are immediately implemented in the next available testing cycle. When compared to other standards development exercises, the NTPEP process is agile, effective, and efficient.

NTPEP Designated Lab:

  • PRI Asphalt Technologies

NTPEP - Asphalt Release Agents


Committee Name:
NTPEP-Technical Committee on Asphalt Release Agents
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Work Plan

NTPEP tests products according to a Project Work Plan, which describes the laboratory and/or field test protocols used to conduct the evaluation. The Project Work Plan is a consensus-based document and includes peer review and input from industry experts. Each Project Work Plan is adopted after receiving at least two-thirds affirmative support from 52 AASHTO member states. The Project Work Plan is the basis for host states to conduct their testing and evaluation. When implemented by state DOTs, their own state standard specifications may supersede the NTPEP Project Work Plan. Industry is advised to be aware of state-level requirements, which may supersede basic NTPEP testing.

Work Plan for NTPEP Evaluation of Asphalt Release Agents​

User Guide

The user guide serves as an overview of the products and testing protocols encompassed by each technical committee. It is the intent of the document to provide basic information about the products and their applications in the field. Furthermore, the document should provide a brief explanation of the test procedures and guidance on how to interpret resulting data.

Asphalt Releas​e Agents User Guide

QC/QA Guide

The Quality Control/Quality Assurance guide is a guidance document that shall outline the methods and practices by which the test facilities shall implement good laboratory practices. This includes, but is not limited to:

  • training requirements
  • certifications
  • equipment calibrations and maintenance
  • data validation

QC/QA Guide for Asphalt Release Agents

Please go to NTPEP DataMine.

Please go to NTPEP DataMine.

Companies or associations that would like to be affiliated with the NTPEP Asphalt Release Agents program should contact Courtney Wallace(cwallace@aashto.org) for additional information.

Overview

  • Evaluation based on AASHTO TP 102, “Evaluation of Asphalt Release ”
  • Evaluation of products that are used for coating tools and truck beds to prevent asphalt binder or hot mix asphalt (HMA) from
  • Asphalt release agents should perform this function without causing degradation (stripping) of the hot mix
  • Products evaluated should not be hazardous for workers to use and should have low or no environmental impact.

 

Evaluation

  • Asphalt Stripping Test – evaluates the susceptibility of stripping of asphalt from aggregates in truck beds and on other paving equipment when using asphalt release agents.
  • Mixture Slide Test – evaluates the susceptibility of a hot mix asphalt (HMA) mixture adhering to the beds of haul trucks or paving equipment when using asphalt release agents.
  • Asphalt Performance Test – determines the susceptibility of hot asphalt binders adhering to plant and paving equipment, rakes, shovels, etc. when using asphalt release
  • Fingerprinting
                  Infrared Spectra, Percent Solids, pH, Specific Gravity, Flash Point
  • Products are re-evaluated every 3 years.

 

Links

 

Success Stories

Brad Young

New Products Engineer

Ohio DOT, Office of Materials Mgmt.

 

One NTPEP program that provides ODOT some benefit, that could easily be used by other states, is the Asphalt Release Agent program.  In speaking with the section that handles these products, they mentioned the following:

    1. The testing done by NTPEP is more thorough than what they used to do.
    2. The NTPEP program ensures that the testing is done by a 3rd party.
    3. Only serious companies with serious products submit to NTPEP because they pay for the testing (weeds out the questionable products).

 

Ohio DOT specification for asphalt release agents

401.11 Hauling. Use trucks for hauling asphalt concrete that have tight, clean, smooth metal beds from which the entire quantity of mixture is discharged smoothly into the spreading equipment.

Before loading, apply a thin coating of an approved release agent to the inside surfaces of the truck bed to prevent adhesion of mixture to the bed surfaces. Office of Materials Management maintains a list of approved release agents.

Link to the Ohio DOT Approved Listing that includes instructions for submitting products for ODOT approval:

http://www.dot.state.oh.us/Divisions/ConstructionMgt/Materials/Asphalt%20Information/Release-Agent-Approved-List.pdf

 


 

Temple K. Short, PE

Materials & Research Operations Engineer

SCDOT Office of Materials and Research

 

South Carolina DOT use of the NTPEP ARA program for asphalt release agents

“Previously flash point and stripping were tested in house.  Using NTPEP laboratory results saves us time and resources and gives us a much more extensive set of data.”


 

Sample Specifications

  • Arkansas DOT ARA method of approval
  • Kansas DOT specification for Release Compounds for Asphalt Mixes
  • Maine DOT qualification of asphalt release agents
  • Texas DOT ARA spec
  • Wisconsin ARA approval process