ارزیابی تأثیر پارامترهای متفاوت بر روی مقاومت بتن در برابر نفوذ یون کلراید و تخلخل آن

نوع مقاله : مقاله پژوهشی

نویسندگان

1 هیئت علمی دانشگاه ازاد واحد تبریز

2 گروه عمران سازه ، دانشکده فنی و مهندسی، دانشگاه آزاد واحد تبریز

چکیده

یکی از عوامل اصلی دوام بتن نفوذپذیری آن است. نفوذپذیری بتن تابع دو عامل سیال عبوری و محیط متخلخل نفوذ است. در این تحقیق برای ارزیابی تأثیر پارامترهای نسبت آب به سیمان (w/c)، نوع و درصد خاکستر بادی بر روی نفوذپذیری بتن، آزمایش‌های نفوذ سریع یون کلراید (RCPT) و تخلخل‌سنجی به روش جیوه (MIP) انجام شد؛ که آزمایش‌ها بر روی آزمونه‌های با نسبت آب به سیمان (w/c) متفاوت و بدون خاکستر بادی و همچنین از آزمونه‌های با نسبت آب به سیمان (w/c) ثابت و خاکستر بادی متفاوت، با گریدهای استاندارد F,C و خاکستر بادی صنعتی ویژه با نام تجاری A، که تشکیل‌دهنده 18 طرح اختلاط بتن می‌باشند، انجام گردید. (تعداد کل نمونه‌ها 216 عدد) انجام گردید. نتایج نشان می‌دهد که کاهش نسبت آب به سیمان (w/c)، باعث کاهش قطر تخلخل و حجم نفوذ می‌شود، اما این امر باعث کاهش سریع کارایی و مشکلات جدید اجرایی می‌گردد و نیز در مقایسه با افزایش درصد خاکستر بادی، تأثیر کمتری بر افزایش مقاومت بتن در مقابل یون کلراید داشته است. همچنین با افزایش درصد هر سه نوع خاکستر بادی باعث کاهش نفوذ سریع یون کلراید، قطر تخلخل و حجم نفوذ می‌گردد و نیز کارایی بتن را افزایش می‌دهد. از نتایج این تحقیق می‌توان دریافت که پارامترهای نسبت آب به سیمان (w/c)، نوع و درصد خاکستر بادی در بتن بر روی نفوذپذیری بتن تأثیر زیادی داشته و باعث افزایش یا کاهش دوام و کارایی بتن گردیده است. نکته جالب در قابلیت انتشار یون کلر در بتن‌های حاوی خاکستر بادی این است که در مواردی که حتی نمونه حاوی خاکستر بادی صنعتی ویژه با نام تجاری A، دارای تخلخل بیشتری نسبت به نمونه شاهد (فاقد خاکستر) بوده باز هم کاهش انتشارپذیری یون کلر به دلیل واکنش‌های ویژه درونی یون کلر با فازهای آلومین مشاهده گردید.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Comparative Evaluation of the Effect of Water/Cement Ratio (w/c), Type and Percentage of Fly Ash on Concrete Strength against Chloride Ion Penetration and Its Porosity

نویسنده [English]

  • Majid Abedi 2
2 Department of Civil Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran
چکیده [English]

In this research, the effect of water-to-cement ratio (w/c), type and percentage of fly ash on concrete permeability, rapid penetration of ion chloride (RCPT), and porosity measurements using mercury (MIP) was performed, which consists of 18 concrete mixing designs (total number of 216 samples). The results show that reduction of water to cement ratio (w/c) decreases porosity and penetration volume, but this results in a rapid reduction of efficiency and new operating problems, and also in comparison with increasing the percentage of ash of wind, Has had a lower impact on the strength of concrete against chloride ion. Also, increasing the percentage of all three types of air ash, reduces the penetration of the ion chloride, porosity, and penetration volume, and also increases the efficiency of the concrete. From the results of this study, it can be seen that the water/cement ratio (w/c), the type and percentage of ash in the concrete have a significant effect on the concrete permeability and have increased or decreased the durability and efficiency of the concrete. An interesting point in the ability to release chlorine ions in wind-blown concrete is that even if the specimen containing the industrial A-type industrial ash contains more porosity than the control sample (ash-free), the reduction of chlorine ion release is due to Internal reactions of chlorine ion with alumina phases were observed.

کلیدواژه‌ها [English]

  • Penetration of chloride ion
  • concrete porosity
  • Water to cement ratio (w/c)
  • fly ash
  • Concrete Permeability
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