Kendiliğinden Yerleşen Betonun Doğrudan Çekme Dayanımına Boyut Etkisinin Araştırılması

Abstract

Özellikle çekme gerilmelerinin kritik seviyede olduğu yapı elemanlarının tasarımında betonun çekme gerilmesi önemli parametrelerden biridir. Yapı şartnamelerinde çoğunlukla bahsedilen çekme dayanımı doğrudan çekme dayanımıdır. Ancak şartnamelerde ifade edilen çekme dayanımları, genellikle basınç dayanımı veya dolaylı yöntemlerle bulunan çekme dayanımlara bağlı formüllerle bulunmaktadır. Doğrudan çekme testlerinin uygulamasının zor olması ve dolaylı yöntemlerde olduğu gibi belli şartname esaslarının olmaması doğrudan çekme dayanımı ile ilgili çalışmaların sınırlı sayıda kalmasına neden olmuştur. Bu nedenle doğrudan çekme testleri ile ilgili yapılan önceki çalışmalarda teste tabi tutulan numune ebatları ve şekilleri ile ilgili belli standartlar oluşmamıştır. Bu çalışmada kendiliğinden yerleşen betonun (KYB) doğrudan çekme dayanımına boyut etkisi incelenmiştir. Bu kapsamda farklı kalınlıklarda dog-bone tipi KYB numunelerin doğrudan çekme dayanımları karşılaştırılmıştır. Deneysel doğrudan çekme dayanımları, deneysel yarmada çekme ve eğilmede çekme dayanımları ile karşılaştırılmış olup aynı zamanda TS500, Eurocode ve ACI 318 gibi yapı şartnamelerinde ifade edilen teorik çekme dayanımlarına yakınlıkları araştırılmıştır. Çalışma neticesinde numune kalınlığı ile doğrudan çekme dayanımı arasında ters orantı olduğu ve numune kalınlıklarının artmasına bağlı olarak, deneysel doğrudan çekme dayanımlarının şartnamelerde belirtilen teorik çekme dayanımlarına yaklaştığı ortaya konulmuştur.

Keywords

• direkt çekme dayanımı
• boyut etkisi
• kyb

Investigation of The Size Effect of Self-Compacting Concrete on Direct Tensile Strength

Abstract

The correct determination of direct tensile strength is very important in reinforced concrete building design. Unless otherwise specified in the building codes, the tensile strength that should be used in building design is direct tensile strength. However, the direct tensile strengths stated in the codes are usually found by formulas based on compressive strength, flexural tensile strength or splitting tensile strength. The fact that direct tensile tests are difficult to apply and there are no clear principles in the building codes, as in indirect methods, have led to a limited number of studies on direct tensile strength. In previous studies on direct tensile tests, certain standards were not established regarding the sizes and shapes of the samples subjected to the test. In this study, the size effect of self-compacting concrete (SCC) on direct tensile strength was investigated. In this context, direct tensile strengths of dog-bone type SCC specimens of different thicknesses were compared. The experimental direct tensile strengths were compared with the experimental splitting and flexural tensile strength, and also their proximity to tensile strengths expressed in certain building codes such as TS500, Eurocode and ACI 318 were investigated. As a result of the study, it was revealed that there is an inverse proportion between the thickness of the specimen and the direct tensile strength, and depending on the increase in the specimen thickness, the experimental direct tensile strengths approached the tensile strengths specified in the building codes.

Keywords

• direct tensile
• size effect
• scc

References

1. [1]. Shi C., Wu Z., Lv K., Wu L., "A review on mixture design methods for self-compacting concrete", Construction and Building Materials, 2015, 84: 387-398.
2. [2]. Öz A., Bayrak B., Aydın A. C., "The effect of trio-fiber reinforcement on the properties of self-compacting fly ash concrete", Construction and Building Materials, 2020, 274: 121825.
3. [3]. Gönen T., Yazıcıoğlu, S., “Pomza agregalı kendiliğinden yerleşen hafif betonların donma çözülme direncine mineral katkıların etkisi”, El-Cezeri Journal of Science and Engineering, 2021, 8(1); 94-101.
4. [4]. Taha M. R., Hassanain M. A., "Estimating the error in calculated deflections of HPC slabs: a parametric study using the theory of error propagation", Acı Special Publications, 2003, 210: 65-92.
5. [5]. Slowik V., Saouma V. E., Thompson A., "Large scale direct tension test of concrete", Cement and Concrete Research, 1996, 26 (6); 949-954.
6. [6]. Contamine R., Larbi A. S., Hamelin P., "Contribution to direct tensile testing of textile reinforced concrete (TRC) composites", Materials Science and Engineering, 2011, A 528.29-30: 8589-8598.
7. [7]. Swaddiwudhipong S., Lu H. R., Wee T. H., "Direct tension test and tensile strain capacity of concrete at early age", Cement and concrete research, 2003, 33 (12): 2077-2084.
8. [8]. Alhussainy F., Hasan H. A., Rogic S., Sheikh M. N., Hadi M. N., "Direct tensile testing of self-compacting concrete", Construction and Building Materials, 2016, 112: 903-906.

9. [9]. Dashti J., Nematzadeh M., "Compressive and direct tensile behavior of concrete containing Forta-Ferro fiber and calcium aluminate cement subjected to sulfuric acid attack with optimized design", Construction and Building Materials 2020, 253: 118999.
10. [10]. Tunc E. T., Alyamaç K. E., Ulucan Z., "A Numerical Approach to Estimate the Tensile Strength of Structural Lightweight Concrete", El-Cezeri Journal of Science and Engineering, 2020, 7 (2): 690-699.
11. [11]. Moradian M., Shekarchi M., "Durability and dimensional stability of steel fiber reinforced cementitious mortar in comparison to high performance concrete", Asian Journal Of Civil Engineering (Building And Housing), 2016: 515-535.
12. [12]. Shin K. J., Jang K. H., Choi Y. C., Lee S. C., "Flexural behavior of HPFRCC members with inhomogeneous material properties", Materials, 2015, 8 (4): 1934-1950.
13. [13]. Krishnaraja A. R., Kandasamy S., Kowsalya M., "Influence of polymeric and non-polymeric fibers in hybrid engineered cementitious composites", Revista Romana de Materiale, 2018, 48 (4): 507.
14. [14]. Bang J. W., Ganesh Prabhu G., Jang Y. I., Kim, Y. Y., "Development of ecoefficient engineered cementitious composites using supplementary cementitious materials as a binder and bottom ash aggregate as fine aggregate", International Journal of Polymer Science, 2015; 2015.
15. [15]. Hassan A. M. T., Jones S. W., Mahmud G. H., "Experimental test methods to determine the uniaxial tensile and compressive behaviour of ultrahigh performance fibre reinforced concrete (UHPFRC)", Construction and building materials, 2012, 37: 874-882.
16. [16]. Sasikala K., Vimala S., "A comparative study of polypropylene, recron and steel fiber reinforced engineered cementitious composites", International Journal of Engineering Research & Technology (IJERT), 2013, 2: 2278-0181.
17. [17]. TS 500, "Betonarme Yapıların Tasarım ve Yapım Kuralları.", (2000).
18. [18]. Eurocode2, "Design of concrete structures.", (2004).
19. [19]. ACI 318-11, "Building Code Requirements for Structural Concrete.", (2011).
20. [20]. Australian Building Codes, "The Australian Building Codes Board.", (2010).
21. [21]. EFNARC Specification, "EFNARC Guidelines for self-compacting concrete.", (2002).
22. [22]. ACI 211.1-91, "Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete.", (1991).
23. [23]. ASTM, C1611, "Standard test method for slump flow of self-consolidating concrete.", (2009).
24. [24]. EN12350-9, "Testing Fresh Concrete—Part 9: Self-Compacting Concrete—V-Funnel Test.", (2010).
25. [25]. Nai T. R., Kumar R., Ramme B. W., Canpolat F., "Development of high-strength, economical self-consolidating concrete", Construction and Building Materials, 2012, 30: 463-469.
26. [26]. Dinakar P., Reddy M. K., Sharma M., "Behaviour of self-compacting concrete using Portland pozzolana cement with different levels of fly ash", Materials & Design 2013, 46: 609-616.
27. [27]. Kim J. K., Han S. H., Park Y. D., Noh J. H., Park C. L., Kwon Y. H., Lee S. G., "23 Experımental Research On The Materıal Propertıes Of Super Flowıng Concrete", Production methods and workability of concrete, 2004, 32: 271.
28. [28]. ASTM C 618-00, "Standard specification for coal fly ash and raw or calcined natural pozzolan for use as a mineral admixture in concrete.", (2004).
29. [29]. EN197-1, "Cement-Part 1: Composition, specifications and conformity criteria for common cements.", (2000).
30. [30]. ASTM C127-15, "Standard Test Method for Relative Density (Specific Gravity) and Absorption of Coarse Aggregate", (2015).
31. [31]. EN12390-3,"Testing hardened concrete-Part 3: Compressive strength of test specimens.", (2002). [32]. ASTM C39/C39M-14a, "Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens", (2014).
32. [33]. ASTM C496/C496 M, "Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens", (2004).
33. [34]. Rocc, C., Guinea G. V., Planas J., Elices M., "Review of the splitting-test standards from a fracture mechanics point of view", Cement and concrete research, 2001, 31 (1): 73-82.
34. [35]. Kadleček V., Modrý S., "Size effect of test specimens on tensile splitting strength of concrete: general relation", Materials and Structures, 2002, 35 (1): 28-34.
35. [36]. EN12390-5. "Testing hardened concrete–Part 5: flexural strength of test specimens.", (2009).
36. [37]. Günaydın O., Güçlüer K., "Bazalt lifi katkılı betonların mekanik özelliklerinin araştırılması", El-Cezeri Journal of Science and Engineering, 2018, 5 (2): 416-424.
37. [38]. Aslani F., Nejadi S., "Self-compacting concrete incorporating steel and polypropylene fibers: Compressive and tensile strengths, moduli of elasticity and rupture, compressive stress–strain curve, and energy dissipated under compression", Composites Part B: Engineering, 2013, 53: 121-133.
38. [39]. Ahmed M., Dad K. M., Wamiq M., "Effect of concrete cracking on the lateral response of RCC buildings", Asian Journal Of Civil Engineering (Building And Housing), 2008, 9 (1): 25-34.
39. [40]. Parra C., Valcuende M., Gómez F., "Splitting tensile strength and modulus of elasticity of self-compacting concrete", Construction and Building materials, 2011, 25 (1): 201-207.
40. [41]. Choi S. J., Yang K. H., Sim J. I., Choi B. J., "Direct tensile strength of lightweight concrete with different specimen depths and aggregate sizes", Construction and Building Materials, 2014, 63: 132-141.
41. [42]. Zhong W., Pan J., Wang J., Zhang C., "Size effect in dynamic splitting tensile strength of concrete: Experimental investigation", Construction and Building Materials, 2020, 270: 121449.