ارزیابی اثر الیاف بر شرایط رشد ترک در بتن غلتکی با استفاده از مدل اصلاح شده دو-پارامتری شکست

نوع مقاله : مقاله پژوهشی

نویسنده

استادیار، گروه مهندسی عمران، دانشکده فنی مهندسی، دانشگاه هرمزگان، ایران

10.22034/tri.2021.258221.2837

چکیده

بتن غلتکی یک مخلوط بتنی با اسلامپ صفر است که بوسیله غلتک برای رسیدن به چگالی لازم متراکم می‌گردد. در مقایسه با بتن معمولی، این بتن با میزان سیمان کمتری به مقاومت یکسان می‌رسد. با این حال، یکی از موانع اصلی در جهت توسعه استفاده از این نوع بتن در روسازی راه، مقاومت اصطکاکی پایین جهت استفاده در راه‌های با سرعت طرح بالا است. با توجه به اینکه در این نوع بتن امکان استفاده از داول در محل درزهای روسازی وجود ندارد استفاده از الیاف جهت مسلح کردن آن و افزایش توانایی انتقال بار می‌تواند گزینه مناسبی باشد. در این تحقیق از دو نوع الیاف ماکروسنتتیک و فلزی جهت مسلح نمودن این نوع بتن استفاده گردید. رفتار ترک خوردگی در مود کششی با استفاده از تیر خمش سه نقطه‌ای و به روش دو-پارامتری شکست مورد ارزیابی قرار گرفت. نوآوری مدل دو-پارامتری اصلاح شده درنظرگیری احتمال تغییر مسیر ترک در حین رشد آن است. نتایج حاصل شده از انجام آزمایش و تحلیل آماری صورت پذیرفته، بیانگر عدم اثرگذاری معنادار الیاف در الگوی رشد ترک مخلوط بتنی است. همچنین با بررسی نتایج پردازش تصویر مشخص گردید که استفاده از روش اصلاح شده دو-پارامتری شکست باعث کاهش خطای محاسبه طاقت شکست در اثر لولا شدن مسیر رشد ترک می‌گردد. حضور الیاف ماکروسنتتیک و فلزی به ترتیب باعث افزایش مدول الاستیسیته به میزان 5/0 و 1 درصد می‌گردد که حاکی از تأثیر گذاری کم الیاف در ناحیه پیش از ترک‌خوردگی بتن است. همچنین در بحث طاقت شکست، الیاف ماکروسنتتیک عملکرد بهتری از خود نشان داد. این در حالی است که الیاف فلزی در ناحیه پس از بار بیشینه، بدلیل مدول و سختی بالا باعث احتمال وقوع ناحیه سخت‌شدگی در نمودار بار-بازشدگی دهانه ترک می‌گردد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluating the effect of fibre on the crack growth of fibre- reinforced roller compacted concrete using two-parameter fracture model

نویسنده [English]

  • Hamed Rooholamini
Assistant Professor, Department of Civil Engineering, Hormozghan University, Hormozghan, Iran.
چکیده [English]

Roller compacted concrete pavement (RCCP) is a zero-slump and stiff-dry mixture which is usually placed with an asphalt paver and compacted by conventional vibratory roller compactors to achieve the required density. RCCP consistently has a slightly lower cement content than conventional concretes of similar strength. Nowadays, RCCP is used for any type of industrial or heavy-duty pavement and has advantages including cost saving as a result of the construction method and the increased placement speed of the pavement. Therefore, the use of RCCP pavement has become more and more popular in recent years. There are numerous studies on the mechanical properties of fibre reinforced focused on cement paste and normal concrete. However, our understanding of what exactly happens when hybrid fibres used to reinforce RCCP mixes with respect to fracture toughness is quite limited. Accordingly, in this study, three point bending test was carried out on mono and hybrid fibre-reinforced RCCP based on modified two-parameter model to determine the value of Mode I plane-strain fracture toughness of fibre-reinforced RCCP by considering possibility of crack deflection during its propagation through modified two-parameter fracture model. Finally, it can be observed that, for great amount of fracture angle, the application of Two-parameter fracture model instead of modified Two-parameter fracture model cause to an overestimation of the fracture toughness values.

کلیدواژه‌ها [English]

  • Roller Compacted Concrete Pavement
  • Fibre
  • Two-parameter fracture model
  • crack kink angle
  • image processing
-ACI committee 544, 3R-08, (2008), “Guide for specifying, proportioning, and production of fibre reinforced concrete”,  American concrete institute, Farmington hills, USA.
-Afroughsabet, V. and Ozbakkaloglu, T., (2015), “Mechanical and durability properties of high-strength concrete containing steel and polypropylene fibers”, Construction and building materials, 94, pp.73-82.
-­Alhozaimy, A.M., Soroushian, P. and Mirza, F., (1996), Mechanical properties of polypropylene fiber reinforced concrete and the effects of pozzolanic materials. Cement and Concrete Composites, 18(2), pp.85-92.
-­American Society for Testing and Materials (ASTM) C1176/C1176M-08, 2008.Standard Practice for Making Roller-compacted Concrete in Cylinder Molds Using a Vibrating Table.
-­Arent, W.L., Kohn, S., Piggott, R.W., Berry, J.R., Larsen, R.L., Ragan, S.A., Cole, L., Lopez, R.W., Rice, J.L., Colucci, B. and McComb, R.A., 1994. State of the art report on roller compacted concrete pavements. ACI Materials Journal, 91(5), pp.509-516.
-­ASTM, A., 820/A 820M-06., (2006), “Standard specification for steel fibers for fiber-reinforced concrete, American Society for Testing and Materials (ASTM) Committee A”, 1.
-­Brandt, A.M., (2008), “Fibre reinforced cement-based (FRC) composites after over 40 years of development in building and civil engineering”, Composite structures, 86(1), pp.3-9.
-­Bremer, R., 1995. Outliers in statistical data.
-­Carpinteri, A., Berto, F., Fortese, G., Ronchei, C., Scorza, D. and Vantadori, S., 2017. Modified two-parameter fracture model for bone. Engineering Fracture Mechanics, 174, pp.44-53.
-­Carpinteri, A., Fortese, G., Ronchei, C., Scorza, D. and Vantadori, S., 2017. Mode I fracture toughness of fibre reinforced concrete. Theoretical and Applied Fracture Mechanics.
-­Code 354, (2009), “Design and construction of roller compacted concrete pavement”, Ministry of Road and Transportation Research and Education Center of Iran.
-­Cotterell, B. and Rice, J., (1980), “Slightly curved or kinked cracks”, International journal of fracture, 16(2), pp.155-169.
-­Delatte, N.J., (2014), “Concrete pavement design, construction, and performance”, Crc Press.
-­Fallah, S. and Nematzadeh, M., )2017(, “Mechanical properties and durability of high-strength concrete containing
macro-polymeric and polypropylene fibers with nano-silica and silica fume”, Construction and Building Materials, 132, pp.170-187.
-­Hesami, S., Ahmadi, S. and Nematzadeh, M., (2014), “Effects of rice husk ash and fiber on mechanical properties of pervious concrete pavement”, Construction and Building Materials, 53, pp.680-691.
-­Hesami, S., Hikouei, I.S. and Emadi, S.A.A., (2016), “Mechanical behavior of self-compacting concrete pavements incorporating recycled tire rubber crumb and reinforced with polypropylene fiber”, Journal of Cleaner Production, 133, pp.228-234.
-­Hoaglin, D.C., Iglewicz, B. and Tukey, J.W., (1986), “Performance of some resistant rules for outlier labeling. Journal of the American Statistical Association”, 81(396), pp.991-999.
-­Jenq, Y. and Shah, S.P., (1985), “Two parameter fracture model for concrete”, Journal of engineering mechanics, 111(10), pp.1227-1241.
-­JSCE-SF4 III, P., (1984), “Method of tests for steel fiber reinforced concrete”, Concrete Library of JSCE, the Japan Society of Civil Engineers.
-­Karadelis, J.N. and Lin, Y., (2015), “Flexural strengths and fibre efficiency of steel-fibre-reinforced, roller-compacted, polymer modified concrete”, Construction and building materials, 93, pp.498-505.
-­Kitagawa, H., Yuuki, R. and Ohira, T., (1975),”Crack-morphological aspects in fracture mechanics”, Engineering Fracture Mechanics, 7(3), pp.515-529.
-­Libre, N.A., Shekarchi, M., Mahoutian, M. and Soroushian, P., (2011), “Mechanical properties of hybrid fiber reinforced lightweight aggregate concrete made with natural pumice”, Construction and Building Materials, 25(5), pp.2458-2464.
-­Lin, Y., Karadelis, J.N. and Xu, Y., (2013), “A new mix design method for steel
fibre-reinforced, roller compacted and polymer modified bonded concrete overlays”, Construction and Building Materials, 48, pp.333-341.
-­Modarres, A. and Hosseini, Z., )2014(, “Mechanical properties of roller compacted concrete containing rice husk ash with original and recycled asphalt pavement material, Materials & Design, 64,
pp.227-236.
-­Pająk, M. and Ponikiewski, T., (2013), “Flexural behavior of self-compacting concrete reinforced with different types of steel fibers.”, Construction and Building Materials, 47, pp.397-408.
-­Rooholamini, H., Hassani, A. and Aliha, M.R.M., (2018), “Evaluating the effect of macro-synthetic fibre on the mechanical properties of roller-compacted concrete pavement using response surface methodology, Construction and Building Materials, 159, pp.517-529.
-­Rooholamini, H., Hassani, A. and Aliha, M.R.M., (2018), “Fracture properties of hybrid fibre-reinforced roller-compacted concrete in mode I with consideration of possible kinked crack”, Construction and Building Materials, 187, pp.248-256.
-­Saidani, M., Saraireh, D. and Gerges, M., (2016), “Behaviour of different types of fibre reinforced concrete without admixture”, Engineering Structures, 113, pp.328-334.
-­Scorza, D., Luciano, R., Mousa, S. and Vantadori, S., (2020), “Fracture behaviour of hybrid fibre-reinforced roller-compacted concrete used in pavements”, Construction and Building Materials, pp.121554.
-­Vantadori, S., Carpinteri, A., Fortese, G., Ronchei, C. and Scorza, D., (2016), “Mode I fracture toughness of fibre-reinforced concrete by means of a modified version of the two-parameter model”, Procedia Structural Integrity, 2, pp.2889-2895.
-­Yew, M.K., Mahmud, H.B., Ang, B.C. and Yew, M.C., (2015), “Influence of different types of polypropylene fibre on the mechanical properties of high-strength oil palm shell lightweight concrete”, Construction and Building Materials, 90, pp.36-43.
-­Yin, Shi, et al., (2015), “Use of macro plastic fibres in concrete: a review, Construction and Building Materials 93”,
pp. 180-188.