Rapid Chemical Method for Determination of Aggregate Alkali Silica Reactivity

The main objective of this study was to develop a fast, reliable test method to determine the aggregate alkali-silica reactivity (ASR) with respect to the overall alkalinity of the concrete. A device, called volumetric change measuring device (VCMD), which measures volume change over time due to ASR was used in this research. The VCMD simulates the aggregate–pore solution reaction in concrete and measures free solution volume contraction due to ASR over time. The solution volume change over time at multiple temperatures is modeled to determine compound activation energy (Ea) based on the rate theory. The VCMD-based test can reliably predict aggregate alkali silica reactivity in a short period of time (5 days) in terms of measuring compound activation energy. A representative Ea can be determined by testing as-received aggregates (i.e., field aggregates) with 0.5N NaOH + Ca(OH)2 solution (similar to concrete pore solution) and with permissible repeatability. Researchers have developed an Ea-based aggregate classification system, which can serve as a potential screening parameter in an aggregate quality control program. A relationship between Ea and alkalinity is developed, which became the basis to determine threshold alkalinity. The proposed method has the potential to be considered as an alternative method to the current accelerated mortar bar test (AMBT) method. An effective way of tailoring mix design depending on the level of protection needed is developed based on activation energy, threshold alkalinity, pore solution chemistry.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; References; Tables;
  • Pagination: 16p
  • Monograph Title: 2014 FAA Worldwide Airport Technology Transfer Conference Proceedings: Innovations in Airport Safety and Pavement Technology

Subject/Index Terms

Filing Info

  • Accession Number: 01538219
  • Record Type: Publication
  • Report/Paper Numbers: P10092
  • Files: TRIS, ATRI, USDOT
  • Created Date: Sep 9 2014 6:35AM