A simple staining technique for the identification of alkali-silica gel in concrete and aggregate

✍ Scribed by A.B. Poole; A. McLachlan; D.J. Ellis

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 250 KB
• Volume: 18
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(88)90128-7

✦ Synopsis

A simple technique is described for staining alkali-silica gel reaction product formed as a result of the interaction between alkali solution and siliceous concrete aggregate particles.

The method involves allowing the developing gel to take up copper ions from a solution of cuprammonium sulphate.

After appropriate washing the gel remains stained blue.

Alternatively, the gel may be dissolved in hydrochloric acid and the copper content, which is proportional to the volume of gel, estimated colorimetrically by neutralising the acid and reforming the blue cupprammonium complex under standard conditions.