بررسی خصوصیات مکانیکی و دوام نمونه‌های بتنی حاوی نانوسیلیس در شرایط باران اسیدی

نویسندگان

1 دانشجوی کارشناسی ارشد، گروه مهندسی عمران، موسسه غیرانتفاعی صائب، ابهر، ایران.

2 دانشجوی کارشناسی ارشد، دانشکده فنی و مهندسی، دانشگاه تهران، تهران، ایران.

3 استادیار، گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه بین‌المللی امام خمینی‌(ره)، قزوین، ایران.

چکیده

در شرایط باران اسیدی واکنش های شیمیایی در سازه بتنی رخ می دهد که منجر به تغییر pH می شود. زمانی که این واکنش ها ادامه می یابند بتن شروع به از دست دادن مقاومت مکانیکی خود می کند که به ترک خوردگی، کاهش وزن و نهایتاً تخریب سازه منجر می گردد. از آنجایی که در مواردی کنترل بارش اسیدی و اثرات آن بر محیط اطراف اجتناب ناپذیر است، تا بحال محققین مطالعات زیادی بر روی این مقوله انجام داده اند و راه کارهایی برای حذف یا کنترل اثرات آن ارائه داده اند. یکی از راه کارهای نوین در این زمینه استفاده از نانوذرات می باشد. در سال های اخیر مطالعات بر روی نانوذرات سیلیس متمرکز شده، با این هدف که بتوان با استفاده از این ماده، مشخصات بتن را بیش از پیش افزایش داد. افزودن نانو سیلیس به بتن در شرایط غیر اسیدی( خنثی) موجب کاهش نفوذپذیری آب درون بتن و همچنین مقاومت بالاتر در برابر حمله های شیمیایی می شود. در این مقاله به بررسی مشخصات مکانیکی و دوام بتن حاوی نانوسیلیس از جمله میزان کاهش وزن، مقاومت فشاری، مقاومت الکتریکی و میزان جذب آب تحت شرایط اسیدی پرداخته می شود. بر اساس نتایج بدست آمده، با افزایش نانوسیلیس به بتن، مشخصات مکانیکی و دوام بتن بهبود می یابد، اما با افزایش درجه اسیدی آب، دوام و مشخصات مکانیکی بتن نزول می یابد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigating the mechanical properties and durability of concrete samples containing Nano-silica under acid rain conditions

نویسندگان [English]

  • Mohammad Fallahshirvani 1
  • Omid Bamshad 2
  • Mahdi Mahdikhani 3
1 MSc student, Department of Civil Engineering, Saeb Nonprofit Institute, Abhar, Iran.
2 MSc student, Faculty of Technical and Engineering, University of Tehran, Tehran, Iran.
3 Assistant Professor, Department of Civil Engineering, Faculty of Technical and Engineering, Imam Khomeini International University (IKIU), Qazvin, Iran.
چکیده [English]

In the conditions of acid rain, chemical reactions occur in the concrete structure, which leads to a change in pH. When these reactions continue, concrete begins to lose its mechanical strength, which leads to cracking, weight loss, and finally the destruction of the structure. Since the control of acid rain and its effects on the surrounding environment is unavoidable in some cases, so far researchers have conducted many studies on this category and have provided solutions to eliminate or control its effects. One of the new solutions in this field is the use of nanoparticles. In recent years, studies have been focused on silica nanoparticles, with the aim of increasing the properties of concrete by using this material. Adding nano-silica to concrete in non-acidic (neutral) conditions reduces water permeability in concrete and also increases resistance against chemical attacks. In this article, the mechanical characteristics and durability of concrete containing nano-silica, including weight loss, compressive strength, electrical resistance, and water absorption rate under acidic conditions are investigated. According to the obtained results, with the increase of nano-silica in concrete, the mechanical properties and durability of concrete improve, but with the increase of water acidity, the durability and mechanical properties of concrete decrease.

کلیدواژه‌ها [English]

  • Nano silica
  • electrical resistance
  • compressive strength
  • water absorption
  • acid rain simulator
[1]     S. Zhao, W. Sun, Nano-mechanical behavior of a green ultra-high performance concrete, Constr. Build. Mater. 63 (2014) 150–160. doi:10.1016/j.conbuildmat.2014.04.029.
[2]     C. Wang, C. Yang, F. Liu, C. Wan, X. Pu, Preparation of Ultra-High Performance Concrete with common technology and materials, Cem. Concr. Compos. 34 (2012) 538–544. doi:10.1016/j.cemconcomp.2011.11.005.
[3]     E.E. Hekal, E. Kishar, H. Mostafa, Magnesium sulfate attack on hardened blended cement pastes under different circumstances, Cem. Concr. Res. 32 (2002) 1421–1427. doi:10.1016/S0008-8846(02)00801-3.
[4]     K. Tosun-Felekoǧlu, The effect of C 3A content on sulfate durability of Portland limestone cement mortars, Constr. Build. Mater. 36 (2012) 437–447. doi:10.1016/j.conbuildmat.2012.04.091.
[5]     M.L. Quinn, Early smelter sites: A neglected chapter in the history and geography of acid rain in the United States, Atmos. Environ. 23 (1989) 1281–1292. doi:10.1016/0004-6981(89)90152-2.
[6]     M.C. Roco, National Nanotechnology Initiative - Past, Present, Future, (2007) 1–42.
[7]     K. Sobolev, How Nanotechnology Can Change the, (2005) 14–18.
[8]     K. Sobolev, S.P. Shah, “ Nanotechnology of Concrete : Recent Developments and Future Perspectives ” NANOTECHNOLOGY IN CONSTRUCTION : IN NEAT AND HYBRID CEMENT HYDRATES, (2014) 2–4.
[9]     M. Jalal, A. Pouladkhan, O.F. Harandi, D. Jafari, Comparative study on effects of Class F fly ash, nano silica and silica fume on properties of high performance self compacting concrete, Constr. Build. Mater. 94 (2015) 90–104. doi:10.1016/j.conbuildmat.2015.07.001.
[10]   D. Adak, M. Sarkar, S. Mandal, Structural performance of nano-silica modified fly-ash based geopolymer concrete, Constr. Build. Mater. 135 (2017) 430–439. doi:10.1016/j.conbuildmat.2016.12.111.
[11]   M.A. Massa, C. Covarrubias, M. Bittner, I.A. Fuentevilla, P. Capetillo, A. Von Marttens, J.C. Carvajal, Synthesis of new antibacterial composite coating for titanium based on highly ordered nanoporous silica and silver nanoparticles, Mater. Sci. Eng. C. 45 (2014) 146–153. doi:10.1016/j.msec.2014.08.057.
[12]   M.S. Morsy, S.H. Alsayed, M. Aqel, Hybrid effect of carbon nanotube and nano-clay on physico-mechanical properties of cement mortar, Constr. Build. Mater. 25 (2011) 145–149. doi:10.1016/j.conbuildmat.2010.06.046.
[13]   I. Navarro-Blasco, M. Pérez-Nicolás, J.M. Fernández, A. Duran, R. Sirera, J.I. Alvarez, Assessment of the interaction of polycarboxylate superplasticizers in hydrated lime pastes modified with nanosilica or metakaolin as pozzolanic reactives, Constr. Build. Mater. 73 (2014) 1–12. doi:10.1016/j.conbuildmat.2014.09.052.
[14]   Y. Qing, Z. Zenan, K. Deyu, C. Rongshen, Influence of nano-SiO2 addition on properties of hardened cement paste as compared with silica fume, Constr. Build. Mater. 21 (2007) 539–545. doi:10.1016/j.conbuildmat.2005.09.001.
[15]   A.M. Said, M.S. Zeidan, M.T. Bassuoni, Y. Tian, Properties of concrete incorporating nano-silica, Constr. Build. Mater. 36 (2012) 838–844. doi:10.1016/j.conbuildmat.2012.06.044.
[16]   G. Li, Properties of high-volume fly ash concrete incorporating nano-SiO 2, Cem. Concr. Res. 34 (2004) 1043–1049. doi:10.1016/j.cemconres.2003.11.013.
[17]   ASTM C 128-01. Standard Test Method for Density , Relative Density ( Specific Gravity ), and Absorption of Fine Aggregate. American Society for Testing and Materials, in: 2003.
[18]   ASTM C 127-01. Standard Test Method for Density , Relative Density ( Specific Gravity ), and Absorption of Coarse Aggregate. American Society for Testing and Materials, (2001).
[19]   ASTM C 136-01. Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. American Society for Testing and Materials, (2001).
[20]   ASTM C 150-07. Standard Specification for Portland Cement. American Society for Testing and Materials, (2008).
[21]   ASTM C143/C 143M-03.Standard Test Method for Slump of Hydraulic-Cement Concrete. American Society for Testing and Materials, (2003).
[22]   ASTM C 109/C 109M-02. Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube Specimens). American Society for Testing and Materials, (2000).
[23]   ASTM C 1202-05. Standard Test Method for Electrical Indicati on of Concrete ’ s Ability to Resist Chloride Ion Penetration. American Society for Testing and Materials, (2017).
[24]   BS 1881, Method for determination of water absorption. British Standards Institution; 2011.
[25]   M. Khanzadi, M. Tadayon, H. Sepehri, M. Sepehri, Influence of nano-silica particles on mechanical properties and permeability of concrete, Second Int. Conf. Sustain. Constr. Mater. Technol. Ancona, Italy, June. (2010) 28–30.
[26]   M. Zahedi, A. Akbar, A. Mohammad, Evaluation of the mechanical properties and durability of cement mortars containing nanosilica and rice husk ash under chloride ion penetration, Constr. Build. Mater. 78 (2015) 354–361. doi:10.1016/j.conbuildmat.2015.01.045.
[27]   S. Fallah, M. Nematzadeh, Mechanical properties and durability of high-strength concrete containing macro-polymeric and polypropylene fibers with nano-silica and silica fume, Constr. Build. Mater. 132 (2017) 170–187. doi:10.1016/j.conbuildmat.2016.11.100.