Effect of composition and content of alkali-active mineral in aggregate on alkali-silica reaction
Petrographic method is used in this experiment to determine a kind of commonly used aggregate alkali activity in Southeast coastal area,the aggregate is composed of altered rock and andesite,and the main mineral composition is silica opal,chalcedony cryptocrystalline glass and epidote.The alkali active mineral content of altered rock is much higher than that of andesite,the expansion rate of altered rock in rapid mortar bar test is greater than that of andesite.SEM and EDS are applied to observe the micro-appearance and analyze the elemental content,and the results indicate that the alkali-active mineral of altered rock is mainly composed of aluminosilicate,Al3+partly replace Si4+when rocks alter,this process increase the adsorption capacity of Na+,and the alkali activity of altered rocks.
petrographic analysisASRNa+adsorptionalkali-active mineral
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