EFFECTS OF HEAT CURING HISTORY ON SILICATE STRUCTURES AND HYDRATION OF ULTRA HIGH STRENGTH HARDENED CEMENT
| Autor: | Koshiro Koizumi, Masaki Sato, Yasuhiro Umemura |
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| Rok vydání: | 2012 |
| Předmět: | |
| Zdroj: | Cement Science and Concrete Technology. 66:515-522 |
| ISSN: | 2187-3313 0916-3182 |
| DOI: | 10.14250/cement.66.515 |
| Popis: | The water-binder ratio of ultra high strength concrete is extremely low；therefore the addition of low-heat portland cement（LC）, moderate-heat portland cement（MC）and silica fume is indispensable at mixing. The influences were discussed from the perspectives of cement hydration required by the Rietveld method using powder X-ray diffraction（XRD）, silica fume hydration by the selective dissolution method and silicate-chain polymerization of hydrate calcium silicate（C-S-H）by the trimethylsilyl（TMS）derivatization method. When curing with the highest temperature of 90℃, pre-curing time is very important for the hydration reaction of W/B＝15％ used with ultra high strength concrete. When 90℃ high temperature heat curing was begun before setting time, cement did not harden or the crack generated it. The hydration of cement and silica fume and generation of C-S-H which performed the history of heat curing, were promoted as compared with normal curing, and the polymerization of the silicate-chain of C-S-H became short.プレキャストコンクリート製造を模擬した熱養生履歴がシリカフューム（SF）を添加した超高強度セメント硬化体において、水和反応およびケイ酸構造へ与える影響について圧縮強度、粉末X線回折（XRD）/リートベルト法による水和反応解析、SFの反応率、トリメチルシリル（TMS）誘導体化法によるC-S-Hのケイ酸鎖の重合の観点から考察した。超高強度コンクリートで用いられるW/B＝15％配合の水和反応は、最高温度90℃養生を行った場合、前置時間を凝結時間よりも長く設定する必要があり、SFおよびセメントの水和反応が材齢91日の20℃封緘養生と比較して促進し、C-S-Hのケイ酸鎖の重合が低下する事を確認した。 |
| Databáze: | OpenAIRE |
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