WTI

Feasibility of Reclaimed Asphalt Pavement as Aggregate in Portland Cement Concrete Pavements

Primary Investigator Contact Information

External Project Contact(s)

Report(s)

There are no reports associated with this project.

Project Objective

The objective of this project is to develop and characterize an environmentally friendly concrete suitable for transportation-related applications in which a portion of the conventional aggregate has been replaced with reclaimed asphalt pavement.

Project Abstract

Each year, the highway construction industry in the United States produces over 100 million tons of reclaimed asphalt pavement (RAP) through standard rehabilitation and construction of our nation’s roads. Although this reusable material has been put to use in some applications (usually in the form of asphalt paving), a large portion of this material remains unused and is either stockpiled or land filled. Therefore, alternative uses for this material are needed. One possible use for this material is the replacement of conventional aggregates in Portland cement concrete pavement (PCCP). There has been limited, preliminary research to demonstrate the feasibility of using RAP in this application. However, these research efforts have focused primarily on short-term mechanical characteristics of the material and have not addressed long-term durability characteristics such as alkali silica reactivity (ASR – which is a deleterious expansive reaction between the alkalis in the Portland cement binder and silicates in the aggregate) or freeze–thaw resistance. Therefore, the proposed research will focus on the durability characteristics of using RAP in Portland cement concrete, which is a critical step in determining whether it can be effectively incorporated into pavements, sidewalks, medians, and other transportation applications. The proposed research effort will begin by developing mix designs with similar strengths, set-times, and workability to conventional concrete mixtures. Once these mix designs are developed, the resulting concretes will be evaluated with a suite of mechanical and durability tests. These results will then be analyzed and documented. Depending on the outcome of this feasibility study, recommendations will be made for a Phase II pilot project in which this material is used in place of traditional concrete in a transportation application. This overall effort is a partnership between WTI, the Montana Department of Transportation (MDT) and the Research and Innovative Technologies Administration (RITA) of USDOT. This project represents the MDT sponsored portion.

Task Descriptions

1. Analysis of Results
   1. The research team will conduct a full analysis of all test results. Comparisons will be made between the different replacement rates, air contents, and control specimens.
2. Comprehensive Determination of Material Properties
   1. Researchers will select two of the most promising mix designs based on the testing in Task 2. They will evaluate these designs further, using a full suite of mechanical tests (compressive strength, elastic modulus, tensile strength, shrinkage and creep) and durability tests (alkali silica reactivity, absorption, abrasion, chloride permeability, freeze-thaw resistance and scaling).
3. Mix Designs and Validation of Key Properties
   1. The research team will create mix designs and validate several key mechanical properties of eight concrete mixtures containing various RAP and air contents.
4. Literature Review
   1. Researchers will conduct a thorough review of previous research related to the use of reclaimed asphalt in pavement construction and rehabilitation.
5. Final Report and Dissemination of Results
   1. The research team will prepare a final report documenting the findings of this investigation. Additionally, the team will prepare journal publications and several key engineering conferences will also be targeted as outlets for dissemination via conference papers and presentations.

Milestones, Dates, Schedule

Student Involvement

False

Relationship to Other Research Projects

False

Technology Transfer Activities

True

Transportation Research Board Keywords

Recycled construction materials, reclaimed asphalt, concrete pavements

Partners

Montana Department of Transportation