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South Dakota Department of Transportation
Project Synopsis
SD2001-10


Title: Lithium Field Implementation Trial
Project Researcher: Dan Johnston, SDDOT
Project Manager: Daris Ormesher
Research Period: 7/1/2002 - 6/30/2007
Status: Approved
Cost: $0.00

Problem Statement:Since 1980 alkali-silica reactivity (ASR) has become an increasingly critical concern with regards to the durability of concrete pavements and structures in South Dakota. The first pavement to exhibit severe ASR was a 38-mile section of I-90 in Lyman County built in 1972. The pavement has continued to deteriorate and become a significant maintenance problem remaining serviceable only due to the presence of the reinforcing. In fact, the worst section is in the process of reconstruction this year. To combat potential problems with ASR in future construction the South Dakota Department of Transportation (SDDOT) adopted the use of Type II, Low Alkali cement in 1983. Contemporary wisdom contended that the use of Portland cement with an equivalent alkali content less than 0.6% would eliminate ASR in concrete even if an aggregate source were deleteriously reactive. Unfortunately, confidence in the assumption has been gradually eroded by the discovery of certain aggregates, mostly volcanic in origin, which undergo ASR even in the presence of a low alkali cement and by the growing awareness of deicing salts as an external source of alkali.

Since 1983 numerous pavements statewide have exhibited various degrees of ASR. In addition, Sioux quartzite, the primary coarse aggregate used in eastern South Dakota, has proven to be reactive. The impact of ASR on concrete durability and pavement life and the need to develop strategies to minimize the risk of premature deterioration of PCC pavements prompted further research. Because the use of lithium salts is a recognized method of mitigating potential ASR in new concrete, SDDOT participated in the Strategic Highway Research Program (SHRP) Concrete and Structures ASR Showcase Test and Evaluation Project 34 Mitigation of Potential Alkali-Silica Reactivity Using Lithium. This work involved the construction of new concrete test sections incorporating various lithium admixtures as well as treatment of a series of 500-foot test sections on an ASR affected severely deteriorated pavement with several dosage levels of lithium nitrate and acetate solutions in 1995. Monitoring of these test sections over the last five years has provided strong evidence of the beneficial effects of lithium treatments on ASR in existing pavements. It has also led to the development of strategies designed to monitor in situ changes in pavement properties that reflect a reduction in the magnitude of expansive stresses. A paper detailing these results, which was presented at the 11th International Conference on Alkali-Aggregate Reaction in June 2000, is attached. The work did not directly address determining the optimum point for applying the treatment or evaluating its cost benefit ratio. This research should address these issues.



Findings:
Title: Lithium Field Implementation Trial
Project Researcher: Dan Johnston, DOT
Project Manager: Daris Ormesher
Research Period: 7/1/2002 - 6/30/2007
Status: Approved
Cost: $0.00

Problem Statement:Since 1980 alkali-silica reactivity (ASR) has become an increasingly critical concern with regards to the durability of concrete pavements and structures in South Dakota. The first pavement to exhibit severe ASR was a 38-mile section of I-90 in Lyman County built in 1972. The pavement has continued to deteriorate and become a significant maintenance problem remaining serviceable only due to the presence of the reinforcing. In fact, the worst section is in the process of reconstruction this year. To combat potential problems with ASR in future construction the South Dakota Department of Transportation (SDDOT) adopted the use of Type II, Low Alkali cement in 1983. Contemporary wisdom contended that the use of Portland cement with an equivalent alkali content less than 0.6% would eliminate ASR in concrete even if an aggregate source were deleteriously reactive. Unfortunately, confidence in the assumption has been gradually eroded by the discovery of certain aggregates, mostly volcanic in origin, which undergo ASR even in the presence of a low alkali cement and by the growing awareness of deicing salts as an external source of alkali.

Since 1983 numerous pavements statewide have exhibited various degrees of ASR. In addition, Sioux quartzite, the primary coarse aggregate used in eastern South Dakota, has proven to be reactive. The impact of ASR on concrete durability and pavement life and the need to develop strategies to minimize the risk of premature deterioration of PCC pavements prompted further research. Because the use of lithium salts is a recognized method of mitigating potential ASR in new concrete, SDDOT participated in the Strategic Highway Research Program (SHRP) Concrete and Structures ASR Showcase Test and Evaluation Project 34 Mitigation of Potential Alkali-Silica Reactivity Using Lithium. This work involved the construction of new concrete test sections incorporating various lithium admixtures as well as treatment of a series of 500-foot test sections on an ASR affected severely deteriorated pavement with several dosage levels of lithium nitrate and acetate solutions in 1995. Monitoring of these test sections over the last five years has provided strong evidence of the beneficial effects of lithium treatments on ASR in existing pavements. It has also led to the development of strategies designed to monitor in situ changes in pavement properties that reflect a reduction in the magnitude of expansive stresses. A paper detailing these results, which was presented at the 11th International Conference on Alkali-Aggregate Reaction in June 2000, is attached. The work did not directly address determining the optimum point for applying the treatment or evaluating its cost benefit ratio. This research should address these issues.



Findings:

Research Objectives:
1  Verify the effectiveness of using lithium nitrate on a pavement that contains reactive aggregate at various levels of ASR severity.
2  Determine the cost benefit of using a topical lithium nitrate treatment for mitigating ASR based on life cycle cost analysis.
3  Develop detailed guidelines for field application of lithium nitrate for mitigation of ASR in existing concrete pavement.

Research Tasks:
1  Review literature pertinent to ASR and its mitigation with lithium.
2  Conduct laboratory tests on concrete slabs using typical coarse and fine aggregate representing a range of ASR reactivity and treat with lithium nitrate. a) Fabricate slab specimens for treatment with lithium nitrate.(minimum size 1' x 1' x 6") b)
3  Identify three existing ASR-deteriorated pavements based on valid selecting criteria such as age, traffic, ASR severity levels, aggregate type and treat the selected pavements with lithium nitrate.
4  Conduct baseline testing of the three selected pavements before treatment.
5  Monitor all test sections ½, 2½, and 4½ years after construction at a minimum. The recommended evaluation and testing are: visual inspection for cracking, static modulus of elasticity, linear expansion, impact echo, lithium nitrate penetration, petro
6  Instrument selected test sections with vibrating wire or fiber optic strain gauges near joints to characterize stress buildup due to expansion prior to ASR-induced cracking.
7  Measure linear expansion of top and sides of the concrete using gauge studs mounted in the pavement.
8  Obtain cores from each test section for petrographic analysis, scanning electron microscopy, and static modulus testing and other testing as necessary.
9  Obtain climate data such as temperature, humidity, and precipitation that is applicable for each test site.
10  Conduct visual and photographic surveys and impact echo testing on all test sections.
11  Estimate life savings and equivalent cost savings based on research results.
12  Prepare design/application criteria covering range of application rates based on the severity of ASR and covering the time of placement to provide the maximum benefit.
13  Prepare construction specifications that address the material requirements, equipment requirements, construction requirements, method of measurement, and bases of payment.
14  Provide a one-page project summary, construction, quarterly and annual evaluation reports.
15  Prepare a final report and executive summary of the literature review, research methodology, findings, conclusions, and recommendations.
16  Make an executive presentation to the SDDOT Research Review Board at conclusion of the project.

Documents Available:
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