تاثیر جریان سرگردان DC بر سازه های بتنی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار، پژوهشکده علوم و تکنولوژی زیر دریا، دانشگاه صنعتی اصفهان

2 استاد، دانشکده مهندسی مواد، دانشگاه صنعتی اصفهان

3 دانشیار، دانشکده مهندسی مواد، دانشگاه صنعتی اصفهان

4 مربی، پژوهشکده علوم و تکنولوژی زیر دریا، دانشگاه صنعتی اصفهان

چکیده

در این مقاله اثرات جریان سرگردان DC بر نمونه‌های بتنی در شرایطی که آرماتورها در معرض خوردگی نیستند (محیط آبی عاری از کلرید)، بررسی شده است. نمونه‌های بتنی با نسبت‌های مختلف آب به سیمان و میکروسیلیس پس از عمل‌آوری به مدت 30 روز در محیط آب مقطر در‌معرض میدان الکتریکیVDC50 قرار گرفت. اثرات میدان مزبور بر بتن با آزمون‌های مقاومت ویژه، طیف‌نگار امپدانس الکتروشیمیایی و آزمون الکتریکی نفوذپذیری مورد بررسی قرار گرفت. بر اساس نتایج، جریان سرگردان DC دارای اثرات منفی بر نفوذپذیری بتن است. کاهش نسبت آب به سیمان و نیز افزودن میکروسیلیس به طرح اختلاط بتن موجب افزایش مقاومت بتن در برابر اثرات منفی جریان سرگردان DC می شود. مکانیزیم پیشنهادی مهاجرت هیدرواکسید کلسیم بتن از طریق گسترش انحلال آن در محلول حفره های بتن و انتقال آن در مسیر میدان الکتریکی است.

کلیدواژه‌ها


عنوان مقاله [English]

Effects of DC Stray Current on Concrete Structure

نویسندگان [English]

  • Abbas Aghajani koupaei 1
  • Mohammad Ali Golozar 2
  • Ahmad Saatchi 2
  • Kyvan Raeissi 3
  • Saeid Shabani 4
1 Assistant Professor, Subsea R&D Center, Isfahan University of Technology
2 Professor, Department of Materials Eng., Isfahan University of Technology
3 Associate Professor, Department of Materials Eng., Isfahan University of Technology
4 Lecturer, Subsea R&D Center, Isfahan University of Technology
چکیده [English]

In this article, effects of DC stray current on concrete structures were studied in chloride free environments. In this article, effects of potential of DC stay current on permeability of concrete in chloride-free aqueous medium were studied. For this purpose, concrete samples with different w/c ratio and silica fume content were subjected to 50 VDC in distilled water for 30 days. The effects of DC stray current on the properties of concrete were determined by resistivity, Electrochemical Impedance Spectroscopy (EIS) and electrical permeability test. The results clearly showed the negative influence of DC stray current on the permeability of the concrete. The critical role of w/c ratio and silica fume additive on the degradation effects created by DC stray current was revealed. Migration mechanism of Ca(OH)2 of concrete under DC stray current was proposed. This process increases pores sizes distribution and creates new pores network in concrete and so increases its permeability. Decreasing w/c or adding silica fume to concrete mix design increase stability of concrete against increasing its permeability by effects of DC stray current.

کلیدواژه‌ها [English]

  • Stray current
  • Concrete
  • Durability
  • Permeability
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