EFFECT OF THE CHARACTERS OF FLY ASH, SO3 CONTENT AND LIMESTONE POWDER ON THE SULFATE RESISTANCE OF FLY ASH BLENDED CEMENTS
| Autor: | Shoichi Ogawa, Takahito Nozaki, Etsuo Sakai, Kazuo Yamada |
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| Rok vydání: | 2012 |
| Předmět: | |
| Zdroj: | Cement Science and Concrete Technology. 66:414-421 |
| ISSN: | 2187-3313 0916-3182 |
| DOI: | 10.14250/cement.66.414 |
| Popis: | Sulfate resistance tests were carried out for various fly ash blended cements by immersing in sodium sulfate solution in order to investigate the effect of characteristics of fly ash, sulfur trioxide (SOз) content and limestone addition. Their hydration products and sulfate ion ingress were evaluated in order to discuss the mechanisms of their effects on sulfate resistance in long term as much as 6 years. After 2 years exposure, sulfate expansions varied obviously with fly ash type, SOз content to blended cement and the use of limestone powder. The more replacement by fly ash more retarded sulfate ion ingress, and the increase in sulfate content or the addition of limestone powder decreased the amount of internal monosulfate that tended to form expansive ettringite with external sulfate ions. When the fly ash which has low alumina in glass phase was used, fly ash blended cement with addition of limestone powder and increase in sulfate content exhibit excellent sulfate resistance for 6 years without internal expansion.フライアッシュ（FA）混合セメントの耐硫酸塩性を、硫酸ナトリウム溶液への最長6年の浸漬による体積変化と、水和物の分析およびSの浸透量で評価した。材齢2年以後の長期材齢ではFAの種類によって、あるいは、SOз量増加または石灰石微粉末（Lsp）添加によって膨張に違いが認められた。FAの添加はSO₄²の浸透を抑制し、SOз量増加またはLsp添加は、供試体内部のモノサルフェートを減少させて外部からのSO₄²浸透によるエトリンガイトの生成を抑制した。ガラス中のAl₂O₃量の少ないFAでは、SOз増加およびLsp添加によっても内部膨張を生じることなく、材齢6年の浸漬でも膨張しない優れた耐硫酸塩性を示した。 |
| Databáze: | OpenAIRE |
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