POWRE: Examination of the Mechanisms of ASR Gel Expansion Control by Lithium Additive in Concrete

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

0074874 Kurtis A POWRE award will support a study of the effects of lithium additives to control expansion by alkali-silica reaction (ASR) in concrete. This reaction occurs between reactive silicates present in some aggregate and pore solution alkalis and produces an alkali-silica gel that is capable of expansion, damaging the affected concrete structure. A more thorough understanding of the mechanisms of expansion control will provide the basis for determining which additives in which dosages should be used in new and existing concrete structures to avoid damage by the reaction. This proposed research is critical for this investigator at this early stage in her career as it will allow her to launch a new research area while building upon her existing knowledge and skills. A key component of the proposed research is the development of the novel application of laser scanning confocal microscopy (LSCM) to examine cement-based materials. Examination of cement-based materials by confocal microscopy has been relatively unexplored, but this technique offers much promise because of the flexible sample preparation requirements, high resolution, and ability to generate three-dimensional representations. Because of their visual impact, these three-dimensional models can be used advantageously in both technical education and public outreach, and several activities have been proposed including the development of two brief tutorials (one appropriate for university education; one appropriate for K-12 education). By demonstrating the utility of this microscopy technique for through-depth examination of concrete to study the alkali-silica reaction, LSCM will find wider applications in concrete technology. Development and refinement of sample preparation protocols, observation methods, and representation formats would establish the investigator as a leader in innovative microscopy of cement-based materials and could lead to additional funding opportunities for the PI. ***