科研之友
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摘要
Gravels, characterized by complex petrographic-mineralogical composition, belong to natural aggregates used in concrete production. Certain gravel components may react with concrete pore solution reach in alkalis hydroxides, causing concrete expansion. The effect of zeolite, composed mainly of clynoptilolite, addition on mortar expansion caused the alkali-aggregate was studied in this work. The chemical method tests, according to ASTM C286 standard, of used gravel has shown that this aggregate is reactive, and these reactions are caused by opal and chalcedony, forming cement in quartz-glauconitic sandstone rock and in sparite-micrite organodetritic limestone. Zeolite addition eliminates the expansion, changing the chemical composition of hydrated sodium-potassium-calcium silicate gel, decreasing sodium content and increasing calcium on the expense of the first. In the areas in which the microcracks appeared the fibres crystals of composition close to philipsite were formed.
- 出版日期2013-10
