Synthesis of Information Related to Airport Practices. Topic S09-08. Approaches to Mitigate Alkali Silica Reaction (ASR) Effects at Airports

Alkali silica reaction (ASR) is pervasive problem in concrete structures in nearly all 50 states in the United States (US). ASR occurs when siliceous aggregate reacts with cement alkali hydroxides within the concrete matrix pores. The reaction creates a gel substance, alkali silica gel, along the aggregate perimeter and within aggregate cracks. The gel absorbs water, expands, and creates tensile stresses within the concrete matrix. The tensile stresses initially are manifested as surface cracking, map cracking, however over time cause large pavement expansion. As stated in the Federal Highway Administration (FHWA) Facts Book, (Thomas et al. March 2013) there are three requirements for the damaging ASR reaction to occur; these are: (1) a sufficient quantity of reactive silica (within aggregates); (2) a sufficient concentration of alkali (primarily from Portland cement); and (3) sufficient moisture. Elimination of any one of these requirements will prevent the occurrence of damaging alkali-silica reaction. Prevention and mitigation of damaging ASR is based upon eliminating or reducing one or more of these three requirements. Concrete mix requirements for new airfield construction are specified in Item P-501 of AC 150/5370-10F (FAA 2011). ASR is avoided through stringent aggregate testing (mortar bar method), limiting the alkalis in the cement, and using Class F fly ash additive. However, many older airfields constructed prior the AC 150/5370-10F requirements are experiencing large slab expansion resulting in cracking due to ASR. Methods to prevent ASR in new highway pavement construction are reviewed in Thomas et al. (December 2013). ASR expansion in concrete structures has now been identified in all 50 states in the US. ASR has been identified at many US commercial airports: Denver and Colorado Springs in Colorado; Hartsfield-Jackson Atlanta International Airport, Georgia; Memphis International, Tennessee; Greenville-Spartanburg Airport, South Carolina; Idaho Falls, Idaho; Regional airports in Wyoming, Albuquerque, and Northwest Arkansas Regional Airport; and Detroit Metropolitan Airport. ASR approaches to retard ASR progression after it has been identified are limited. Approaches typically use sealants to prevent water intrusion, however, pavement joints open and close and therefore allow a path for water intrusion into the pavement areas adjacent to the pavement joints. Identification of ASR in pavements has often been described as a death sentence for those pavements. Airports are looking for measures to take that can reduce the likelihood of deleterious expansion in airport pavements from ASR. Review of current approaches used for mitigating ASR effects at airfield pavement sections along with new approaches for ASR mitigation for new pavement construction would be useful to airports. The following data shall be collected and compiled in a concise report. Current ASR mitigation approaches. (1) Use of fly ash class C and F; (2) Use of Slag; (3) Use of lithium nitrate; and (4) Use of Silca fume. New approaches for ASR mitigation for new construction. (1) Use of a specialty cement such as calcium sulfoaluminate cement; (2) Using a new test for screening aggregates; (3) New or improved additives; (4) Use of fiber material in the mix; (5) Reducing the number of joints by having greater slab sizes; (6) Decreasing the porosity of the concrete mix to reduce water and deicer infiltration; and (7) Reducing the pH of the concrete mix. The principal investigator will conduct a literature review, and a screening survey to identify airports experiencing runway ASR damage, in addition to those identified above. These airports will be surveyed and /or interviewed to determine extent of damage, any mitigation performed, and steps taken to ensure ASR mitigation for new construction. A concise report will be written that summarizes the results of the literature review, survey and interviews. The report will include exemplary practices from the airports studied, as well as gaps in knowledge and recommended research.


  • English


  • Contract Numbers:

    Project 11-03, Topic S09-08

  • Sponsor Organizations:

    Airport Cooperative Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC    20001

    Federal Aviation Administration

    800 Independence Avenue, SW
    Washington, DC  United States  20591
  • Project Managers:

    Staba, Gail

  • Start Date: 20161029
  • Expected Completion Date: 0
  • Actual Completion Date: 0
  • Source Data: RiP Project 41205

Subject/Index Terms

Filing Info

  • Accession Number: 01615480
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 11-03, Topic S09-08
  • Files: TRB, RiP
  • Created Date: Oct 29 2016 1:00AM