Yüksek Performanslı Hafif Betonlarda Donatı Çapı ile Aderans Gerilmesi Arasındaki İlişki

Öz

Yüksek performanslı hafif beton (YPHB), yapı mühendisliğinde yeni ve güncel bir konudur. Kalıcı ve uzun ömürlü yapılar inşa edebilmek için YPHB’lere ihtiyaç vardır. YPHB ile kullanılacak toplam beton miktarı azaltılarak binaların hafiflemesi mümkündür. Günümüzde en büyük afetlerden olan deprem riskinin yüksek olması nedeni ile YPHB’lere olan ihtiyaç artmıştır. Betonarmenin varlığı, aderans olayına bağlıdır. YBHB’lerin aderans gerilmesi birçok parametreye bağlı olarak değişmektedir. Bu çalışmanın amacı, farklı donatı çapı ve farklı kenetlenme boyu gibi değişim parametreleri ile YPHB’lerin beton-donatı aderansı arasındaki ilişkinin deneysel olarak belirlenmesidir. Bu amaçla pomza agregaları kullanılarak farklı karışım oranları ve farklı beton bileşenlerine sahip YPHB’ler hazırlanmıştır. Bu kapsamda 100×180×800 mm boyutlarında YPHB kiriş numuneler hazırlanmış ve üretilen numuneler Standart Belçika Mafsallı Kiriş (BMK) deneyine tabi tutulmuştur. YPHB kirişlerin aderans özelliklerinin Standart Belçika Mafsallı Kiriş deneyi ile araştırılması konusunda literatürde sınırlı sayıda çalışma bulunmaktadır. Söz konusu çalışma bu yönü ile dikkat çekmektedir. Mevcut çalışmada Ø8 ve Ø10 çaplarında nervürlü çelik donatı çubukları kullanılmış ve her bir donatı çapı için 10Ø ve 20Ø kenetlenme boyları dikkate alınarak BMK numuneleri üretilmiş ve aderans deneyleri yapılmıştır. Deneyde düşey olarak uygulanan ve yük hücresi yardımı ile okunan P yükü kullanılarak dolaylı olarak bulunan donatıdaki F kuvvetinin yardımı ile donatıda meydana gelen aderans gerilmesi hesaplanmıştır. Yapılan deneyler sonucunda aderans gerilmesi ile donatı çapı ve kenetlenme boyu arasında önemli bir ilişki olduğu tespit edilmiştir. Aderans gerilmesinin beton basınç dayanımının artmasıyla arttığı, donatı çapı ve kenetlenme boyunun artması ile azaldığı belirlenmiştir.

Anahtar Kelimeler

• Yüksek Performanslı Hafif Beton
• Belçika Mafsallı Kiriş
• Aderans Gerilmesi
• Donatı Çapı
• Kenetlenme Boyu

Relationship between Reinforcement Diameter and Bond Stress in High Performance Lightweight Concrete

Abstract

High performance lightweight concrete (HPLC) is a new and original research in structural engineering. Due to the high risk of earthquakes, which is one of the biggest disasters today, the need for HPLCs has increased. The purpose of this study is to experimentally research concrete-reinforcement bond for the change parameters such as different reinforcement diameters and different embedded lengths. For this purpose, HPLCs with different mix ratios and different concrete components were prepared by using pumice aggregates. Within this scope, HPLC beam specimens of 100×180×800 mm dimensions were prepared and produced specimens were subjected to the Standard Belgium Hinged Beam (SBHB) test. There are limited studies in the literature on the investigation of the bond properties of HPLC beams with this test. The mentioned study draws attention with this aspect. In the present study, ribbed steel reinforcement bars with different diameters were used. The beam specimens were produced considering the different embedded lengths for each reinforcement diameter. The bond tests were performed. Using the load applied vertically and read with the help of the load cell in the experiment, the bond stress occurring in the reinforcement was calculated with the help of the force in the reinforcement indirectly found. As a result of the experiments, it has been determined that there is a significant relationship between bond stress and reinforcement diameter and embedded length. It has been determined that the bond stress decreases with the increase of reinforcement diameter and embedded length.

Keywords

• High Performance Lightweight Concrete (HPLC)
• Beam
• Bond stress
• Reinforcement

Kaynakça

1. Aitcin, P. C. (1998). High performance concrete. CRC press.
2. Al-Khaiat, H and Haque, M. N. (1998). Effect of initial curing on early strength and physical properties of a lightweight concrete. Cement and Concrete Research, 28(6), 859-866.
3. Arslan, M. E. and Arslan, T. (2018). Investigation of Development Length and Rebar Diameter Effects on Bond Strength by Using Hinged Beam Test. Science and Engineering Journal of Firat University, 30(2), 1-11. (in Turkish).
4. Arslan, M. E. and Durmus, A. (2011). Investigation of bond behavior between lightweight aggregate concrete and steel rebar using bending test. Computers and Concrete, 8(4), 465-472.
5. ASTM C 293, 1994. Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Center-Point Loading), Annual Book of ASTM Standards.
6. Baena, M., Torres, L., Turon, A. and Barris, C. (2009). Experimental study of bond behaviour between concrete and FRP bars using a pull-out test. Composites Part B: Engineering, 40(8), 784-797.
7. Benli, A., Türk, K. and Calayır, Y. (2008). Numerical and Experimental Investigation of Bond Strenght of Beams Produced from Self-Compacting Concrete. Science and Engineering Journal of Firat University, 20(4), 599-607. (in Turkish).
8. Beycioğlu, A., Arslan, M. E., Bideci, O. S., Bideci, A., Emiroglu, M. 2015. “Bond behavior of lightweight concretes containing coated pumice aggregate: Hinged beam approach” Computers and Concrete, 16(6), 911-920.

9. Bingöl, A. and Gül, R. (2009). A Reassessment on the Bond Strength Between Reınforcement and Concrete and the Effect of High Temperatures on the Concrete and on the Bond Between Concrete and Reinforcement. Turkish Science-Research Foundation, 2(2), 211-230. (in Turkish).
10. BS 4449:2005+A2:2009.Steel for the reinforcement of concrete—Weldable reinforcing steel—Bar, coil and decoiled product.
11. Chandra, S. and Berntsson, L. (2003). Lightweight Aggregate Concrete. Noyes Publications, USA, 1-430.
12. De Larrard, F., Shaller, I. and Fuchs, J. (1993). Effect of the bar diameter on the bond strength of passive reinforcement in high-performance concrete. Materials Journal, 90(4), 333-339.
13. Diederichs, U. and Schneider, U. (1981). Bond strength at high temperatures. Magazine of Concrete Research, 33(115), 75-84.
14. Durmuş, A., Dahil, H. and Arslan, M. E. (2006). Comparative Investigation of High Performance Concrete-Reinforcement Adherence. Turkey Engıneerıng News, 441. (in Turkish).
15. El Zareef, M. (2010). Conceptual and Structural Desıgn of Buıldıngs Made of Lıghtweıght And Infra-Lıghtweıght Concrete. Master of Science. Von der Fakultät VI – Planen Bauen Umwelt der Technischen Universität Berlin.
16. Ersoy, U. and Özcebe, G. (2001). Reinforced concrete: basic principles. Calculation According to TS500 and Turkish Earthquake Code. Ankara. (in Turkish). Ersoy, U., 1985. Reinforced concrete. Evrim Publishing. ,(in Turkish).
17. Haque, M. N., Al-Khaiat, H. and Kayali, O. (2004). Strength and durability of lightweight concrete. Cement and Concrete Composites, 26(4), 307-314.
18. Hoff, G.C., 1990. High-Strength Lightweight Aggregate Concrete. ACI SP(121), 619- 644 p.
19. Hossain, K. M. A. (2004). Properties of volcanic pumice based cement and lightweight concrete. Cement and concrete research, 34(2), 283-291.
20. Hosseini, S. J. A., Rahman, A. B. A., Osman, M. H., Saim, A. and Adnan, A. (2015). Bond behavior of spirally confined splice of deformed bars in grout. Construction and Building Materials, 80, 180-194.
21. Ince, R. and Çetin, S. Y. (2019). Effect of grading type of aggregate on fracture parameters of concrete. Magazine of Concrete Research, 71(16), 860-868.
22. Karatas, M., Turk, K. and Ulucan, Z. C. (2010). Investigation of bond between lap-spliced steel bar and self-compacting concrete: the role of silica fume. Canadian Journal of Civil Engineering, 37(3), 420-428.
23. Neville, A. M. (1995). Properties of concrete (Vol. 4). London: Longman.
24. Poon, C. S., Shui, Z. H. and Lam, L. (2004). Compressive behavior of fiber reinforced high-performance concrete subjected to elevated temperatures. Cement and Concrete Research, 34(12), 2215-2222.
25. Saglam, R.N., Tunc, E. T., Demir, T., Ulucan, M. and Alyamac, K.E. (2019). Structural Lightweight Concrete Produced With Perlite Aggregate – A Preliminary Mix Design. International Civil Engineering and Architecture Conference (ICEARC 2019).
26. Tanyıldızı, H. and Yazıcıoğlu, S. (2006). Effect of Mineral Admixtures on Bond Strength of Concrete and Reinforcement. Science and Engineering Journal of Firat University, 18(3), 351-357. (in Turkish).
27. TS 802, 2016. Concrete Mix Calculation Principles. Turkish Standardization Institute (in Turkish).
28. TS EN 12390-5, 2002. Hardened Concrete Tests, Chapter 5: Determination of Flexural Strength of Test Samples, Turkish Standards Institute, Ankara. (in Turkish).
29. TS EN 197-1, 2002. General cements-Composition, properties and suitability criteria. Turkish Standards Institute, Ankara. (in Turkish).
30. TS EN 933-1: 2012. Experiments for the geometric properties of aggregates part 1: Determination of grain size distribution-Sieving method. Turkish Standards Institute, Ankara. (in Turkish).
31. Tugrul Tunc, E. (2020). “Determination of Bond Properties in High Performance Lightweight Concrete.” Ph. D. thesis, Firat University, Elazığ. (in Turkish).
32. Tunc, E. T. and Alyamac, K. E. (2019). A preliminary estimation method of Los Angeles abrasion value of concrete aggregates. Construction and Building Materials, 222, 437-446.
33. Tunc, E. T., Alyamaç, K. E. and Ulucan, Z. (2020). A Numerical Approach to Estimate the Tensile Strength of Structural Lightweight Concrete. El-Cezeri Journal of Science and Engineering, 7(2), 690-699.
34. Tunç, E. T., Alyamaç, K. E., Ragıp, İNCE and Ulucan, Z. Ç. (2018). Investigation of mechanical properties of high-performance lightweight concrete with pumice aggregate. Engineering Sciences, 13(4), 344-353.
35. Tunc, E. T., Saglam, R.N., Ulucan, M., Demir, T., Ulucan, Z.Ç. and Alyamac, K.E. (2019). A Preliminary Mix Design For Structural Lightweight Concrete Produced With LECA. International Civil Engineering and Architecture Conference (ICEARC 2019).
36. Ulusu, İ., 2007. “Investigation to production of high strength light weight concrete with using raw perlite aggregate.” Ph. D. thesis, Atatürk University, Erzurum. (in Turkish).
37. Wasserman, R. and Bentur, A. (1996). Interfacial interactions in lightweight aggregate concretes and their influence on the concrete strength. Cement and Concrete Composites, 18(1), 67-76.
38. Xiao, J. and König, G. (2004). Study on concrete at high temperature in China—an overview. Fire safety journal, 39(1), 89-103.