The goal of this research is to evaluate plant-produced HMA mixtures that contain RAS to identify the critical material properties and plant operations needed to produce RAS mixtures with fatigue and low temperature cracking properties equivalent (or better than) typical mixtures that are produced. Research objectives:
- Determine the current state-of-practice for recycled shingle usage in paving mixtures.
- Locate regional asphalt mixture producers in New England with capabilities and willingness to produce mixtures incorporating RAS for this study. From this list of producers, select producers so that both batch and drum plant are utilized for production.
- Assist the selected producers in evaluating the properties of the RAS and RAP to be used in production.
- Construct a matrix of mixtures that will be produced. An all-virgin material control mixture, 5% RAS mixture and a 5% RAS + RAP mixture will be designed.
- Assist the selected producers in developing laboratory mixture designs utilizing RAS that meet the required volumetric criteria.
- Produce the mixtures using a batch plant and drum plant. Produce mixtures assuming 100% blending of the RAS and virgin binder and at the calculated actual RAS binder contribution.
- Sample the mixture at the plant and verify volumetric properties. Mixtures not meeting the volumetric properties should be produced again with alteration to the production parameters (use higher temperatures, longer silo storage or increased mixing times).
- Construct a matrix for evaluating the performance of the mixtures with emphasis of low temperature and fatigue cracking. The matrix should contain a component to evaluate the effect of aging on the degree of blending between aged and virgin binders.
- Identify critical material properties and plant operations that yield RAS mixtures with performance properties equivalent to typical all-virgin material mixtures.
- Develop a guideline for the use of RAS in virgin and RAP mixtures.
Progress/Accomplishments Through March 31, 2015
- UMass Dartmouth contacted several producers of asphalt mixtures in New England about their availability and willingness to participate in the study. One contractor located in Massachusetts agreed to produce the necessary mixtures to fulfill the objectives of the study.
- Work commenced on the literature review for this project.
- UMass Dartmouth continued to contacted several producers of asphalt mixtures in New England about their availability and willingness to participate in the study. Due to inclement weather no mixtures were able to be produced this quarter.
Technical Committee Members
- Denis M. Boisvert (Chairperson), New Hampshire Department of Transportation
- Michael Byrne, Rhode Island Department of Transportation
- Leo Fontaine, Connecticut Department of Transportation
- Edmund Naras, Massachusetts Highway Department
- Derek J. Nener-Plante, Maine Department of Transportation