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FHWA Publishes Report on Alkali-Silica Reactivity in Concrete

Map cracking symptoms of alkali-silica reaction (ASR) in concrete Alkali-silica reaction in concrete.

Transtec Study Reveals Latest Findings on Preventing, Identifying and Mitigating ASR Concrete Distress

AUSTIN, TX, September 1, 2010—The United States Federal Highway Administration (FHWA) released the second report of a two-part series of reports on Alkali-Silica Reactivity (ASR) entitled, Report on the Diagnosis, Prognosis, and Mitigation of Alkali-Silica Reaction (ASR) in Transportation Structures (FHWA Report No. FHWA-HIF-09-004).  This report, written by The Transtec Group (Transtec), outlines the proper methods and decision-making processes to assist engineers of State Departments of Transportation (DOTs) and other agencies in identifying, mitigating, and monitoring ASR in concrete structures.

ASR is a phenomenon occurring between the alkali hydroxides in the pore solution of concrete and “reactive” aggregates, which can lead to significant expansion and cracking in concrete.  Over the course of several years, if left untreated, this distress can compromise the serviceability and performance of large and small-scale concrete structures.

Engineers and contractors across the nation needed better guidance to determine the most appropriate methods of identifying ASR in their concrete pavements and structures, and to decide the proper course of treatment.  As a result, the FHWA initiated the ASR Development and Deployment Program in 2007.  Transtec is now the prime contractor for the implementation of ongoing ASR research, which has led to the improvement of the decision-making process for preventing and mitigating ASR in new and existing concrete.

The first of this two-part series report, Determining the Reactivity of Concrete Aggregates and Selecting Appropriate Measures for Preventing Deleterious Expansion in New Concrete Construction (FHWA Report No. FHWA-HIF-09-001) was released in 2008 and describes approaches for identifying deleteriously reactive aggregates and selecting appropriate measures to prevent ASR in new concrete.  Combined with the newly released report, engineers and users can improve the way ASR is treated and prevented, both in the lab and in the field.

Both reports are available for download at no cost on FHWA’s ASR website,  For more information about these reports or the progress of the ASR Development and Deployment Program, please contact Gina Ahlstrom at or Bebe Resendez at

About The Federal Highway Administration Pavement Technology Program: An agency of the United States Department of Transportation, FHWA carries out the federal highway programs in partnership with the state and local agencies to meet the nation’s transportation needs.  The goal of FHWA’s Pavement Technology Program is to provide leadership and technology for the delivery of long life pavements that meet customers’ needs and are safe, cost effective, and can be effectively maintained.  For more information about FHWA, please visit

About The Transtec Group: The Transtec Group is a pavement engineering firm that provides expertise in pavement design, research, construction, rehabilitation, software development, Public-Private Partnership (P3) projects and technology transfer for the transportation industry. A DBE and MBE firm, Transtec is a leader in Design-Build transportation projects worldwide. Transtec is based in Austin, Texas and serves clients throughout the world. For more information, please visit