Assessment of Various Mitigation Strategies of Alkali-Silica Reactions in Concrete and Implementing Outlier Detection Method in Industrial Applications
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Saudi Digital Library
Abstract
The mitigation of Alkali-Silica Reaction (ASR) has become more urgent than ever before due
to the high demand for concrete in an increasingly industrialized world with expanding urban
infrastructure. This study investigates the efficacy of additives in cement mixtures as an effort
of stopping or mitigating Alkali-Silica Reactions that damage the structural integrity of concrete
members. While there is existing research on certain supplementary cementitious materials
(SCMs) and their role in stopping ASR in concrete, the present study is distinguished by using
various binary supplementary cementitious materials (SCMs) such as Metakaolin and waste
glass powder as replacement for cement. A new cement product called NewCem Plus was also
investigated as a cement replacement at various percentages. In addition, the effectiveness of
other materials and admixtures such as basalt fiber and lithium were also examined. The ASTM
C1260 14-day accelerated mortar bar test was used for this study, and all supplementary
materials were tested separately according to ASTM standards. Moreover, concrete properties
such as compressive strength and concrete flow test were also evaluated in order to complement
the test results. Our preliminary findings showed that Metakaolin could effectively be
implemented in concrete mixtures as an ASR mitigation waste-by-product. In the samples with
10%, 20%, and 30% where Metakaolin was added as cement replacement, the expansion was
79%, 84%, and 88% less than that of the control mixture. The glass powder decreased the
expansion of control specimens by 20%, 43%, and 75% at the 10%, 20%, and 30% replacement
levels, respectively. The addition of lithium to the Metakaolin mitigated the ASR. Lithium by
itself was effective when added to the Metakaolin and glass powder mixtures, where it reduced
the expansion below the threshold limit, which is 0.1%. The cement replacement of 10% with
glass powder + lithium resulted in 0.209% expansion (51% reduction). However, the reduction
for the 20% and 30% was not enough to pass the ASTM test, and the total expansion went
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above the 0.1% total expansion safe limit of the test. The mixtures of NewCem Plus (NCM)
and Lithium were not an effective solution for ASR reduction in concrete.
The test results of the other two materials, glass powder, and basalt fibers, showed variations
between reducing and increasing the expansion level based on their percentages of cement
replacements. Although the concrete expansion was slowed, it was not kept under the safe level
of 0.10% as recommended by ASTM 1260. Finally, the experimental results point positively to
the simultaneous addition of multiple SCMs and additives in cement mixtures to further
increase its numerous properties. In addition, a comprehensive cost analysis of all the
ingredients used in all mixtures was performed. The results showed that the cost would be 50%
less compared to the control mixtures (100% cement) to 655% more when basalt fibers were
used. The manufacturer shall perform a life cycle assessment before the final decision of the
inclusion of such materials. This study showed the feasibility of using binary and ternary blends
of SCMs in mitigating ASR in concrete, and it shows a comprehensive representation of how
those materials should be included in concrete moistures for future applications.
The second topic of this dissertation was focused on the application of data mining in detecting
outliers in concrete testing results and how that is important to stakeholders and decision
makers. The rapid development in the construction industry has induced a large amount of
concrete data over the years, which are usually measured and analyzed every day. Concrete is
made from numerous ingredients that have huge variability either at the design stage or at the
testing stage. The main