مصالح و سازه های بتنی

مصالح و سازه های بتنی

بررسی تأثیر مدت عمل‌آوری بر خواص بتن قلیافعال سرباره‌ای تک‌جزئی در محیط غیراشباع

نوع مقاله : مقاله پژوهشی

نویسندگان
1 دانشجوی دکتری سازه دانشگاه گیلان
2 استاد دانشکده فنی و مهندسی دانشگاه گیلان-رشت-ایران
چکیده
این تحقیق به بررسی اثر مدت زمان عمل‌آوری بر خواص بتن قلیا فعال سرباره‌ای تک جزئی (O-AAS) می‌پردازد و آن را با بتن سیمان پرتلند معمولی (OPC) مقایسه می‌کند. عمل‌آوری تا سنین ۱، ۷، ۲۸، ۵۶ و ۳۶۰ روز انجام شد. پس از عمل‌آوری، نمونه‌ها تا ۳۶۰ روز در محیط با رطوبت نسبی ۵۰ درصد نگهداری شدند. آزمایش‌های انجام شده شامل مقاومت فشاری، ضریب انتشار یون کلرید، جمع شدگی آزاد و جمع شدگی مقید بودند. همچنین، مغزه‌گیری از مرکز ستون های بتنی برای آزمایش مقاومت فشاری و ضریب انتشار یون کلرید انجام شد.

نتایج نشان داد که افزایش مدت‌زمان عمل‌آوری به‌طور قابل‌توجهی موجب بهبود خواص بتن O-AAS در مقایسه با OPC شده است. در شرایط غیر اشباع، عدم تأمین عمل‌آوری کافی منجر به کاهش تا ۳۷ درصدی مقاومت فشاری ۳۶۰ روزه در بتن O-AAS شد. افزایش مدت عمل‌آوری از ۱ به ۷ روز، جمع‌شدگی آزاد را تا ۱۷.۶ درصد و عرض ترک ناشی از جمع‌شدگی مقید را تا ۶۰ درصد کاهش داد. بررسی مغزه‌ها نشان داد که در صورت عمل‌آوری ناکافی، ریزترک‌ها به نواحی درونی بتن O-AAS نفوذ کرده و موجب کاهش دوام و مقاومت شده است. با افزایش مدت عمل‌آوری از 1 روز به 7 روز در بتنO-AAS، آثار این ریزترک‌ها بر روی دوام و مقاومت مشاهده نشده است. در مقابل، نمونه‌های مغزه‌گیری‌شده از بتن OPC در شرایط ۱، ۷ و ۳۶۰ روز عمل‌آوری، تفاوت معناداری در نتایج مقاومت و نفوذپذیری نشان ندادند.

یافته‌ها بر ضرورت تأمین شرایط مناسب عمل‌آوری در سنین اولیه برای حفظ عملکرد بلندمدت بتن O-AAS، به‌ویژه در محیط‌های غیراشباع، تأکید دارند.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Effect of Curing Duration on the Properties of One-part Alkali-Activated Slag Concrete in an Unsaturated Environment

نویسندگان English

Hamed Zanganeh 1
Ali Sadrmomtazi 2
1 Ph.D. Candidate, Civil Engineering, University of Guilan
2 Professor, Department of Civil Engineering, University of Guilan
چکیده English

This study investigates the effect of curing duration on the properties of one-part alkali-activated slag (O-AAS) concrete and compares its performance with that of ordinary Portland cement (OPC) concrete. The specimens were cured under ambient moist conditions for 1, 7, 28, 56, and 360 days. Following curing, all samples were stored in an environment with 50% relative humidity for up to 360 days. The experimental program included compressive strength, chloride ion diffusion coefficient, free shrinkage, and restrained shrinkage tests. Additionally, core samples were extracted from the center of concrete columns to evaluate compressive strength and chloride ion diffusivity.

The results showed that increasing the ambient moist-curing duration significantly enhanced the performance of O-AAS concrete compared to OPC. Under unsaturated conditions, insufficient curing led to a reduction of up to 37% in the 360-day compressive strength of O-AAS concrete. Extending the curing period from 1 to 7 days reduced free shrinkage by 17.6% and the width of 28-day restrained shrinkage cracks by 60%. Core analysis revealed that inadequate curing resulted in the penetration of microcracks into the inner zones of O-AAS concrete, adversely affecting its mechanical and durability performance. However, increasing the curing duration from 1 to 7 days eliminated the influence of such internal microcracking. In contrast, OPC core specimens exhibited no significant differences in compressive strength and chloride ion diffusion between 1-day, 7-day, and 360-day curing regimes.

Overall, the findings underscore the critical importance of providing adequate early-age curing for O-AAS concrete to ensure long-term durability and mechanical performance, especially in unsaturated environments.

کلیدواژه‌ها English

One-Part Alkali-Activated Slag Concrete
Chloride Ion Diffusion Coefficient
Curing Duration
Aging
Shrinkage cracking
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  • تاریخ دریافت 11 مرداد 1404
  • تاریخ بازنگری 23 شهریور 1404
  • تاریخ پذیرش 03 آبان 1404