U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
|This report is an archived publication and may contain dated technical, contact, and link information|
Publication Number: FHWA-HRT-06-069
Date: February 2006
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The process of selecting candidate structures (and appropriate components of structures) for lithium treatment invariably involves sampling one or several components of the structures for laboratory investigations, particularly petrographic examination, and expansion tests (expansion tests optional). This sampling is done to (1) confirm whether alkali-silica reactivity (ASR) is an important part of the deterioration process, (2) determine the extent of the deterioration and, (3) if required, determine how much more expansion/deterioration is to be expected. Figures 1 and 2 show the types of cracking that can be a visual indication of a candidate for lithium treatment.
Figure 1. Extensive map cracking in several concrete barriers along State Highway 2 near Leominster, MA.
Figure 2. Closeup view of cracking on concrete barrier along State Route 2 near Leominster, MA.
To help evaluate the potential cause(s) of distress, it is important to collect and report whatever data are available. The following types of information should be provided to the petrographer:
Figure 3. Coring equipment being used to extract a 10-centimeter (4-inch) diameter core from a concrete barrier.
Figure 4. Closeup of an extracted core from a concrete barrier.
Protocol for Selecting ASR-Affected Structures for Lithium Treatment (FHWA-RD-04-113) and the TechBrief for the report (FHWA-HRT-06-071) provide information on the basic petrographic observations and tests that can be performed in the laboratory.(7)
Assistance can be provided to the State departments of transportation in developing the proposal, especially in the analysis of the field evidence of the ASR, the evaluation of the petrographic features of the ASR, and the mechanical testing of samples taken from candidate structures. See figures 5, 6, 7, 8, and 9.
Figure 5. Polished surfaces of three concrete cores. The size, shape, and color of the coarse aggregate particles and their distribution in the concrete are shown. (Photograph by Dr. P.E. Grattan-Bellew)(8)
Figure 6. Polished surfaces of three concrete cores. The extensive cracking in the cores is shown. (Photograph by Dr. P.E. Grattan-Bellew)(9)
Figure 7. Example of a polished concrete surface.
Figure 8. An example of a thin section concrete sample.
Figure 9. Polished surface of a concrete core photographed in ultraviolet light. The arrows show the gel that has filled in the cracks in the quartzite aggregate and in the cement paste. (Photograph by Dr. P.E. Grattan-Bellew)(9)
FHWA currently is conducting a series of research activities under the lithium technology program; its research activities are overseen by Fred Faridazar. He can be reached at 202–493–3076 or firstname.lastname@example.org.
Researchers—This study was performed by The Transtec Group, Austin, TX. The research team includes Dr. Kevin Folliard (University of Texas at Austin), Dr. Michael Thomas (University of New Brunswick), Dr. Benoit Fournier (CANMET/ICON), and Ms. Yadhira Resendez (The Transtec Group).
Distribution—This TechBrief is being distributed according to a standard distribution. Direct distribution is being made to the Divisions and Resource Center.
Availability—This document will be available as an appendix in the report Interim Recommendations for the Use of Lithium to Mitigate or Prevent ASR. This document may be obtained from the FHWA Product Distribution Center by e-mail to email@example.com, by fax to 301–577–1421, or by phone to 301–577–0818.
Key Words—Aggregates, alkali-silica reaction, alkali-aggregate reaction, cracking, diagnosis of ASR, expansion, field inspection, gel, lithium, lithium treatment, petrographic examination, prognosis of ASR.
Notice—This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document.
Quality Assurance Statement—The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.
Topics: research, infrastructure, pavements and materials
Keywords: research, infrastructure, pavements and materials, Aggregates, alkali-silica reaction, alkali-aggregate reaction, cracking, diagnosis of ASR, expansion, field inspection, gel, lithium, lithium treatment, petrographic examination, prognosis of ASR
TRT Terms: research, facilities, transportation, highway facilities, roads, parts of roads, pavements, lithium, alkali silica reactions, petrography, cracking