Alkali-Silica Reaction (ASR) remains a significant durability concern for concrete infrastructure and
continues to present challenges for transportation agencies. Existing ASR test methods often involve the
tradeoff between speed and reliability. Accelerated methods can produce false positives and false
negatives, while more reliable expansion-based methods may require several months or years to
complete.
Research project RP#2024-11 evaluated an extended version of the T-FAST test (Turner-Fairbank Alkali
Silica Reaction (ASR) Aggregate Susceptibility Test) by AASHTO TP144, for quantifying ASR risk in hardened
concrete. Significant progress has been made through the evaluation of aggregates with known reactivity,
development of and experimental database, and assessment of variables affecting the Reactivity Index
(RI), including curing conditions, immersion solutions, and use of fly ash and silica fume for ASR mitigation.
As the research progressed, several new variables were identified that were not included in the original
scope but are important for continued validation of the method. This Technical Transfer project will
further advance the Extended T-FAST method by: (i) incorporating additional aggregates with
documented reactivity; (ii) evaluating interactions between fine and coarse aggregates; (iii) refining the
RI classification framework using classification algorithms; and (iv) supporting the statistical analysis
needed to develop a standardized test procedure.
