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بررسی اثر پارامترهای فرایندی روانکننده های بر پایهی پلیکربوکسیلات بر عملکرد آنها در بتن | ||
| علوم و فنون سازندگی | ||
| دوره 6، شماره 1 - شماره پیاپی 18، مرداد 1404، صفحه 31-37 اصل مقاله (791.89 K) | ||
| نوع مقاله: مقاله پژوهشی | ||
| نویسندگان | ||
| محمدعلی قنبری1؛ محمدرضا طهرانچی* 2 | ||
| 1دانشجوی دکتری، مدیر مرکز تحقیقات بتن شهید رجایی- موسسه شهید رجایی-هلدینگ راه و شهرسازی | ||
| 2کارشناسی ارشد، موسسه شهید رجایی، تهران، ایران | ||
| تاریخ دریافت: 17 بهمن 1401، تاریخ پذیرش: 09 مهر 1402 | ||
| چکیده | ||
| فوقروانکنندهها جزو مهمترین مواد افزودنی بتن هستند که با کاهش گرانروی و تنش تسلیم بتن تازه باعث بهبود روانی آن خواهندشد. یکی از پرکاربردترین مواد فوقروانکننده رایج در صنعت بتن، فوقروانکنندههای بر پایه پلیکربوکسیلات هستند. این مواد در اثر جذبشدن بر روی سطح ذرات سیمان و با سازوکار قالب ممانعت فضایی از بههمچسبیدن ذرات در بتن جلوگیری کرده و باعث بهبود روانی آن میشوند. در پژوهش انجامشده، تاثیر پنج نوع فوقروانکننده بر روی خواص ملات و بتن تازه و سختشده مورد بررسی قرار گرفت. نتایج به دست آمده نشان میدهد که بر اساس آزمونهای شیمیایی هر پنج نوع فوقروانکننده از نوع پلیکربوکسیلات با گروههای عاملی یکسان هستند و تفاوت آنها در جرم مولی و طول شاخههای جانبی آنها است. در نهایت با توجه به عملکرد هر پنج نوع فوقروانکننده مشخص شد که با افزایش طول زنجیر پلیمر و طول شاخههای جانبی و همچنین افزایش درصد مواد جامد فوقروانکننده، گرانروی پلاستیک ملات و بتن کاهش مییابد، زیرا ممانعت فضایی زنجیرهای پلیمری جذبشده بر سطح ذرات سیمان افزایش یافته و امکان تجمع این ذرات که باعث کاهش روانی بتن میشود کاهش مییابد. در اثر استفاده از ماده افزودنی ضدکف نیز هوای محبوس در بتن کاهش مییابد، اما با افزایش مقدار آن از یک مقدار بهینه، آبانداختگی بتن افزایش و کارایی آن کاهش مییابد. | ||
| کلیدواژه‌ها | ||
| مواد افزودنی بتن؛ فوقروانکننده؛ پلیکربوکسیلات؛ جریانشناسی | ||
| عنوان مقاله [English] | ||
| The investigation of Polycarboxylate process parameters on concrete properties | ||
| نویسندگان [English] | ||
| mohammadali ghanbari1؛ Mohammadreza Tehranchi2 | ||
| 1Director of Shahid Rajaei Concrete Research Center | ||
| 2سرباز وظیفه نخبه | ||
| چکیده [English] | ||
| Superplasticizers are among the most important concrete additives that will improve the flow of fresh concrete by reducing its viscosity and yield stress. One of the most commonly used superplasticizers in the concrete industry are polycarboxylate-based superplasticizers. As a result of being absorbed on the surface of cement particles, these materials prevent particles from sticking together in concrete with the mechanism of spatial hindrance and improve its flow. In the conducted research, the effect of five types of superplasticizers on the properties of fresh and hardened mortar and concrete was investigated. The obtained results show that based on chemical tests, all five types of polycarboxylate superplasticizers are the same with functional groups and their differences are in molar mass and the length of their side branches. Is. Finally, according to the performance of all five types of superplasticizers, it was found that with the increase in the length of the polymer chain and the length of the side branches, as well as the increase in the percentage of superplasticizer solids, the viscosity of plastic mortar and concrete decreases. Because the steric hindrance of polymer chains absorbed on the surface of cement particles increases and the possibility of accumulation of these particles, which reduces the flow of concrete, decreases. Due to the use of anti-foam additive, the air trapped in the concrete is reduced, but by increasing its amount from an optimal value, the water permeability of concrete increases and its efficiency decreases. | ||
| کلیدواژه‌ها [English] | ||
| Additives, Superplastiszers, Polycarboxylate, Rheology | ||
| مراجع | ||
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