A rapid method for identification of alkali reactivity of aggregate

✍ Scribed by Tang Ming-shu; Han Su-fen; Zhen Shi-hua

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 380 KB
• Volume: 13
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(83)90042-x

✦ Synopsis

A rapid method for the identification of alkali reactivity of aggregate within two days has been achieved. Ixlx4 cmmortar bars with cement:aggregate -10:1, w/c -0.3, size of aggregate -0.15-0.75~mwere demolded after one-day curing and subjected subsequently to 100°C steam curing for 4 hours, after which they were iauuersed in 10Z KOH solution and autoclave-treated at 150°C for 6 hours. After each stage of curing expansion measurements were carried out. From the data of more than thirty species of rocks, the authors arrived at the conclusion that the rapid method could be used to distinguish reactive and non-reactlve aggregate.

The results of microscopic observation made clear that the expansion of mortar bars was caused by alkall-sillca reaction. This method cannot only be used to identify the alkali reactivity of aggregate, but when combined with the use of optic and electron microscope, can be also used to study the mechanism of alkall-aggregate reaction.