بررسی اثر آب به سیمان و حجم الیاف فولادی در پارامترهای شکست بتن خودمتراکم حاوی الیاف فولادی

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشجوی دکتری سازه، دانشکده مهندسی شهید نیکبخت ، دانشگاه سیستان و بلوچستان، زاهدان، ایران

2 استاد، دانشکده مهندسی شهید نیکبخت، دانشگاه سیستان و بلوچستان، زاهدان، ایران

3 دانشیار ، دانشکده مهندسی شهید نیکبخت، دانشگاه سیستان و بلوچستان، زاهدان

چکیده

در این تحقیق اثر نسبت اب به سیمان و درصد حجمی الیاف فولادی بر روی پارامترهای شکست بتن خو متراکم به دو روش کار شکست و اثر اندازه مورد بررسی قرار گرفته است. در یک برنامه ازمایشگاهی نسبت آب به سیمان و درصد حجمی الیاف فولادی متغییر در نظر گرفته شده ، بدین منظور 5 طرح اختلاط در 2 سری ساخته شده است که در سری اول نسبت اب به سیمان متغییر (شامل مقادیر 42/0 ، 52/0 و62/0 )و درصد الیاف فولادی مقدار ثابت 3/0 درصد در نظر گرفته شده و در سری دوم درصد الیاف فولادی متغییر ( شامل 1/0 ، 3/0 و 5/0 درصد )و نسبت اب به سیمان مقدار ثابت 52/0 در نظر گرفته شده است. نتایج نشان می دهد که با افزایش نسبت آب به سیمان انرژی شکست کاهش و بتن تردتر میشود هر چند که در نسبت آب به سیمان کمتر شاهد رفتار متفاوتی می باشیم و همچنین با افزایش درصد الیاف فولادی انرژی شکست افزیش و بتن شکل پذیر تر می گردد، همچنین نتایج نشان می دهد افزایش در صد الیاف فولادی می تواند در کاهش اثر اندازه موثر باشد. انرژی شکست در روش کار شکست نسبت به روش اثر اندازه مقدار بیشتری دارد و نسبت GF/Gf برای تمام طرح اختلاط ها محاسبه شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Studying Water to Cement Ratio and Steel Fiber Volume Fraction Effects on the Self-Compacting Steel Fiber-reinforced Concrete Fracture Parameters

نویسندگان [English]

  • mohammad ghasemi 1
  • mohammad reza ghasemi 2
  • Seyed Roohollah Mousavi 3
1 department of civil engineering velayat univercity, iranshahr , iran
2 departemen of civil engineering, university of sistan and balochestan, zahedan, iran
3 Assistant Professor, Dept. of Civil Engineering, Univ. of Sistan and Baluchestan
چکیده [English]

In this research, efforts were made to study the effects of water to cement ratio (W/C) and steel fiber volume fraction (V_f (%)) on the fracture parameters of self-compacting steel fiber-reinforced concrete using both Work Fracture and Size Effect Methods. In an experimental program, a variety of water to cement ratio and volume of steel fibers were considered and five mix designs were prepared in two series. In the first, water to cement ratio were altered (Includes values :W/C=0.42, 0.52, and 0.62) with a constant volume of steel fiber (V_f=0.3%), and in the second, varied volume of steel fibers (Includes values: V_f=0.1, 0.3, and 0.5%) with a constant water to cement ratio (0.52) were considered. Results have shown that an increase in the water to cement ratio reduces the fracture energy, However, we see a different behavior in the lower water to cement ratio, while an increase in the volume of steel fiber not only increases the fracture energy causing the concrete to become more ductile, but it can also reduce the size effect greatly. G_F⁄G_f has been found for all mix designs about 11.81 and it has been concluded that the work fracture method yields more fracture energy than the Size effect method.

کلیدواژه‌ها [English]

  • Fiber reinforced concrete
  • Fracture energy
  • Steel fiber
  • Self-compacting concrete
  • Size effect
[1] Nehme S.G., Lászl R., Mir A.E., Mechanical performance of steel fiber reinforced self-compacting concrete in plane, Procedia Engineering, 2017; 196:90 – 96
[2] Fuente A, Pujadas P, Blanco A, Aguado A, Experiences in Barcelona with the use of fibres in segmental linings. Tunneling and Underground Space Technology  2012;27:60–71
[3] Iqbal sh, Ali A, Holschemacher  A, Bier TH. Mechanical properties of steel fiber reinforced high strength lightweight self-compacting concrete (SHLSCC). Constr. Build. Mater 2015;98:325–333
[4] Azhdary MoghaddaM M., Miri M., Rigi M., The effect of rebar coating types on bars corrosion of self-compacting concrete, JSCE, 2017: 172-185
[5] Sanginabadi K., Rostami R., Habibi N., Mostofinejad D., Zarrebini M., Fracture mechanics of fiber reinforced concrete: Experimental study of composition, geometry and hybridization of fibers, JSCE, 2018: 83-94
[6] Madandoust R, Ranjbar M.M, Ghavidel R, Shahabi F. Assessment of factors influencing mechanical properties of steel fiber reinforced self-compacting concrete. Mat.  Des. 2015;83:284–294
[7] Hillerborg A. Results of three comparative test series for determining the fracture energy GF of concrete. Mater Struct 1985;18:407–413
[8] Bazant Z, Pfeiffer P, Determination of fracture energy from size effect and brittleness number, ACI Mater. J 1987;84:463–480.
[9] Alberti MG, Enfedaque A, Galvez  JC. Comparison between polyolefin fibre reinforced vibrated conventional concrete and self-compacting concrete. Constr . Build. Mater 2015;85: 182–194
[10]-Kazemi M.T., Golsorkhtabar H., Beygi M.H.A, Gholamitabar M., Fracture properties of steel fiber reinforced high strength concrete using work of fracture and size effect methods, Constr. Build. Mater. 2017;142: 482–489
[11] Ghasemi M., Ghasemi M.R., Mousavi S.R., Investigating the effects of maximum aggregate size on self-compacting steel fiber reinforced concrete fracture parameters, Constr. Build. Mater. 2018;162:  674–682.
[12] ] Karamloo M., Mazloom M., Payganeh G.,Influences of water to cement ratio on brittleness and fracture parameters of self-compacting lightweight concrete, Engineering Fracture Mechanics, 2016; 168: 227-241
[13] Sahin Y, Koksal F. The influences of matrix and steel fibre tensile strengths on the fracture energy of high-strength concrete. Const. Build. Mater, 2011;25:1801–1806
[14] RILEM FMC-50. Determination of the fracture energy of mortar and concrete by means of three-point bend tests on notched beams. Mater Struct 1985;18(4):287–290.
[15] ASTM C 1609/C 1690M-07. Standard test method for flexural performance of fiber reinforced concrete (using beam with third-point loading) 2007: 1–8
[16] RILEM TC-169-SOC. Indirect test for stress-crack opening curve 2007
[17] RILEM TC-89. Size-effect method for determining fracture energy and process zone size of concrete. Mater Struct 1990;23(6):461–465.
[18] Bazant ZP , Kazemi MT, Determination of fracture energy, process zone length and brittleness number from size effect, with application to rock and concrete, IJFr  1990;44:111–131
[19] EFNARC, The European Guidelines for Self-Compacting Concrete, Specification, Production and Use  2005
[20] Bazant ZP, Becq-Giraudon E, Statistical prediction of fracture parameters of concrete and implications for choice of testing standard, Cem. Concr. Res, 2002;32:529–556.
[21] Dupont L., Vandewalle L., Distribution of steel fibres in rectangular sections, Cem. Concr. Compos. 2005;27:391–398.