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South Dakota Department of Transportation
Project Synopsis
SD1999-02


Title: Mitigation of Deterioration Due to ASR or ACR on Existing PCC Pavements and Structures
Project Researcher: Sidney Scott, Trauner Assoc.
Project Manager: Daris Ormesher
Research Period: -
Status:
Cost: $0.00

Problem Statement:South Dakota and numerous surrounding states are experiencing shortened service life on PCC pavements with Alkali-Silica and Alkali-Carbonate Reactive Aggregate (ASR and ACR). Although we have instituted measures to mitigate deterioration in new concrete construction, we still have numerous pavements containing reactive aggregate that will deteriorate as time passes. Treating these existing pavements with one or more processes to delay the onset or slow down the rate of deterioration would be an extremely cost effective means of extending pavement life with minimum maintenance costs. Prior research in South Dakota has examined the effectiveness of polymers, silanes and lithium compounds at reducing the rate of reaction of aggregate or holding severely cracked pavements together. The overall results have been favorable and indicate that these measures can add significant life to pavements that would otherwise have to be overlaid or rebuilt.

A test method does not exist that is capable of evaluating the condition of a concrete pavement with regard to the effectiveness of a surface treatment in delaying the rate of alkali aggregate reaction (AAR). A variety of technologies such as impact echo, static modulus, and radar are being used to evaluate the condition or severity level of a pavement. However, these test methods have not been able to quantify the degree that AAR has affected the concrete. It is imperative that a test method be developed or an existing method refined before attempting to evaluate concrete treatments.

The research would focus on developing a cost effective treatment(s) for AAR on affected pavements including treatments with lithium solutions, applications of high molecular weight methacrylates (HMWM) or other polymer systems and silanes used individually or in tandem applications. The project would probably involve a cooperative effort such as a pooled fund project with adjacent states or a interaction with university researchers looking for appropriate field test sites. The primary focus of the research is when should the treatment be applied to realize the greatest benefit. The research would take advantage of extensive prior research and yield guidelines for ASR mitigation in existing pavements based on pavement condition severity.



Findings:

Research Objectives:
1  To develop a analytical method to evaluate various treatments for mitigating AAR in existing concrete pavements and predict their remaining service life.
2  To evaluate the effectiveness of various treatments treatments for mitigating AAR in existing concrete pavements and the appropriate application time.
3  To determine the cost-effectiveness of each treatment treatments for mitigating AAR in existing concrete pavements.

Research Tasks:
1  Meet with the project’s technical panel to review the project scope and work plan.
2  Review and summarize literature pertinent to prediction of AAR deteriation and deteration rate in concrete.
3  Develop a cost effective analytical method to classify ASR and ACR severity and determine rate of deterioration or remaining life. This would include but not be limited to developing of sampling and test procedures and prepare cost and time estimate
4  Develop performance parameters to be evaluated in determining the effectiveness of the various treatments. This would include but not be limited to application rate, application method, cost, penetration, environmental and health hazards, how well it
5  Determine number of test sections, number of treatments, and number of pavement severity types to be evaluated.
6  Select pavement test sections with the aid of SDDOT.
7  Meet with technical panel to review the status of the project. This will be a decision point to determine if project should continue based on success of tasks one (1) through six (6).
8  Apply different treatments to selected pavement sections considering factors to be evaluated in task four.
9  Observe placement of test sections and document pavement conditions, treatment, location, rate, and any other pertinent information.
10  Determine frequency and length of the evaluation period.
11  Evaluate the test sections using the method(s) developed in Phase I.
12  Analyze data and determine the benefit/cost ratio for each treatment.
13  Develop a decision tree to determine proper treatment type and rate of application for a particular pavement severity and material type.
14  Prepare a final report and executive summary of the literature review, research methodology, findings, conclusions, and recommendations.
15  Make an executive presentation to the SDDOT Research Review Board at conclusion of the project.

Documents Available:
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