Physical Sciences and Mathematics Commons^™

A Geochemical Analysis: Application Of A Chelating Agent On Potential Asr Reactive Aggregates, Jennifer N. Garcia

Geosciences Theses

Alkali Silica Reaction (ASR) is a deleterious, expansive reaction in concrete. Several ASTM methods test potential aggregates for ASR risk. One method uses NaOH digestion, followed by spectroscopic methods, to estimate the amount of reactive silica present in an aggregate. NaOH, however, can digest both crystalline (i.e. quartz) and non-crystalline (e.g. opal), or poorly crystalline silica, potentially yielding falsely high estimates of reactive silica. Studies in soil and plant sciences have used Tiron, an alkaline chelating agent (C₆H₄S₂O₈Na₂), as a method of digesting opaline silica for spectroscopic analysis. Here we …