Understanding the Role of SCMs in Mitigating Alkali-Silica Reaction

Описание: The requirements for an ideal ASR test method are that it should
be rapid, reliable, and capable of determining the influence of
aggregate reactivity, alkali availability, and exposure conditions.
None of the currently available or commonly used methods meet
all of these criteria. The current approach of ASR testing and the
mitigation of the damaging effects of ASR depends heavily on
accelerated mortar-bar methods and the formulation of prescriptive
mixture designs.

While this approach has resulted in significant advances that
avoid damaging ASR in structures, it was found to be insufficient
in some cases. The concrete prism test has been considered to be
the best index for field performance, but the test duration
imposes a major drawback. There is growing demand for a rapid,
reliable ASR test method. The recent advances in understanding
current test methods and new test methods and approaches to test
method development will be presented. The use of nondestructive
evaluation (NDE) as a tool to better understand test results will
also be highlighted.

Although the main chemical reactions that result in deleterious
ASR are well known, the mechanisms by which supplementary
cementitious materials mitigate ASR are not well understood. An
improved understanding of the way mitigation techniques can
control ASR will be presented. The results of long-term exposure
of concrete with ASR mitigation techniques will also be discussed.