ÇEPER ETKİSİ OLUŞMAYAN FARKLI BİÇİM VE BOYUTTAKİ BETON NUMUNELERİN BASINÇ DAYANIMLARININ DENEYSEL KARŞILAŞTIRILMASI

Yıl 2014, Cilt: 6 Sayı: 3, 29 - 48, 01.09.2014

Can Demirel Ahmet Gökdemir

Öz

Beton basınç dayanımında geometrinin önemine ait birçok çalışma yapılmıştır. Bu çalışmada da beton numunelerde geometrinin ve narinliğinin önemini görmek için çeper etkisi oluşumu engellenerek basınç dayanımları incelenmiştir. 28 günlük basınç dayanımları incelendiğinde en yüksek dayanım 100 mm ayrıtlı küp numune olan 100G’de 34,133 değeri ile elde edilmiştir. Standart numune olan 150 mm ayrıtlı küp numunede ise 33,600 Mpa değeri elde edilmiş ve en az 30 Mpa olması gereken değer sağlanmıştır. En az 25 Mpa değeri aranan 150x300 mm silindir numunede 27,633 Mpa dayanım elde edilirken 100x200 mm silindir numunede 29,500 Mpa’lık dayanım elde edilmiştir. Kimyasal kür uygulanan numunelerde ise beklenenin aksine fazla bir dayanım artışı olmazken bu tür malzemelerin küçük yüzey alanlardaki etkisinin çok olmadığı tespit edilmiştir. Yapılan deneysel çalışma sonucu sahada kullanılan beton karışımını içindeki maksimum agrega boyutuna uygun numune kalıbı seçilmesinin daha doğru olacağı tespit edilmiştir. Ayrıca farklı geometrideki numuneler arasında geçiş katsayıları ve çeşitli modeller önerilmiştir.

Anahtar Kelimeler

Çeper Etkisi, Beton Numune, Basınç Dayanımı, Beton Karışım

EXPERIMENTAL COMPARISON OF CONCRETE SPECIMENS HAVING DIFFERENT FORM AND SIZES WITHOUT WALL EFFECT FORMATION

Öz

Many studies have been done on geometry’s importance in concrete compression resistance. In this study because of seeing the importance of geometry and slimness in concrete samples, compression resistances have been analysed by preventing the wall effect process. If the 28-day-compression resistances are examined, the highest resistance is obtained from the 100 mm-edged cube sample in 100G with the value 34,133. In the 150 mm-edged cube sample which is a standard sample, the value 33600 Mpa is obtained and the minimum value is provided that must be 30 Mpa. In the 150x300 mm cylinder sample looking for the minimum value 25 Mpa, 27,633 Mpa resistance is obtained while in the 100x200 mm cylinder sample resistance of 29,500 Mpa is obtained. In chemical cure performed samples resistance increase isn’t very much on the contrary it has been determined that effects on small surfaces of this kind of materials aren’t very much. By the result of the experimental study it has been fixed that it would be useful to choose sample formwork necessary for maximum aggregate size in concrete mixture used in the field. Furthermore pass parameters between samples in different geometry and various models have been suggested.

Anahtar Kelimeler

Wall Effect, Concrete Sample, compressive strength, Concrete Mixtur

Kaynakça

• Mindess. S., Young. J.F., Darwin. D., Concrete, United States of America, Prentice Hall Pearson Education, 2003.
• Tokyay, M., Özdemir, M., Specımen shape and sıze effect on the compressive strength of hıgher strength concrete. Cement and Concrete Research, Vol. 27, No. 8. 1281-1289, 1997.
• Van Mier, J.G.M. Strain-softening of concrete under multiaxial loading conditions. PhD thesis, Eindhoven University of Technology, Eindhoven, The Netherlands, 1984.
• H.F. Gonnerman, Proc. ASTM, 25, Part 2,237-250, 1925.
• Sabnis, G.M., and Mirza, S.M., Size Effect in Model Concrete. Journal of the Structural Division, ASCE, V. 105, No. 6, 163-177, June 1979,
• Neville, A.M., A General Relation for Strength of Concrete Specimens of Different Shape
• and Size. ACI Journal, V. 63, No. 10, 1095-1110, Oct. 1966.
• Bauschinger, J. Tests with blocks of natural stone. Mech Tech Lab Kgl 1876.
• İnce, R., and Arici, E., Size effect in bearing strength of concrete cubes. Construction and Building Materials, V.8 No.18, 603-609, 2004.
• Meyerhof, GG., The bearing capacity of concrete and rock. Mag Concrete Res 4(12) 107–116, 1953.
• Shelson, W., Bearing capacity of concrete. J Am Concrete Inst Pro 54(5), 405–414, 1957
• Au, T., Baird, DL., Bearing capacity of concrete blocks. J Am Concrete Inst Proc 56(9), 869–879, 1957.
• Hawkins, N.M., Discussion of references. J Am Concrete Inst Proc 56(9), 1469–1479, 1960.
• Hawkins, N.M. The bearing strength of concrete loaded through rigid plates. Mag Concrete Res., 19(4), 20:31, 1968
• Niyogi, S.K., Concrete bearing strength-support, mix, size effect. J Struct Div-ASCE, 100, 1685–1701, 1974.
• Tanigawa, Y., and Yamada, K., Size Effect in Compressive Strength of Concrete. Cement and Concrete Research, V.8, No.2, 181-190, Feb. 1978..
• Carpinteri, A., Ferro, G., and Monetto, I., Scale Effects in Uniaxially Compressed Concrete Specimens. Magazine of Concrete Research, V.51, No.3, 217-225. June 1999.
• Issa, S.A., Islam, Md.S., Issa, M.A., Yousif, A.A., and Issa, M.A., Specimen and Aggregate Size Effect on Concrete Compressive Strength. Cement, Concrete and Aggregates, V. 22, No. 2, 103-115, Dec. 2000.
• Day, R.L., Haque, M.N., Correlation between strength of small and standard concrete cylinders. ACI Materials Journal, 90(5), 452-462, 1993.
• Felekoğlu, B., Türkel, S., Effects of Specimen Type and Dimensions on Compressive Strength of Concrete. G.U. Journal of Science, 18(4), 639-645, 2005.
• Motaz, M.E. and Theodor, K. Dynamic Size Effect in Normal- and High-Strength Concrete Cylinders. ACI Materials Journal, 102 (2), 77-85, 2005.
• Türkel, A. and Özkul, H., Size and Wall Effects on Compressive Strength of Concretes. ACI Materials Journal, 107(4), 372-379, 2010.
• Patnaik, A.K. and Patnaikuni I., Correlation of strength of 75 mm diameter and 100 mm diameter cylinders for high strength concrete. Cement and Concrete Research 32 (2) 607– 613, 2002.
• Del Viso, J.R., Carmona, J.R., Ruiz, G., Shape and size effects on the compressive strength of high-strength concrete. Cement and Concrete Research, 38 (5), 386–395, 2008.
• Tuncan, M., Arioz, O., Ramyar, K., Karasu, B., Assessing concrete strength by means of small diameter cores. Construction and Building Materials, 22(1), 981–988, 2008.
• Smeplass, S., High Strength Concrete, SP4-Materials Design. Report 4.4 Mechanical
• Properties-Normal Density Concrete 1989.
• Held, M., Darrnstadt Concrete, 5 1990.
• Carasquillo, P.M. and Carasquillo, R.C. AC1 Journal, 85 (1), 49-54, 1988.
• Lessard, M. and Aitcin, P-C., High Performance Concrete. Y. Malier, ed. E&FN Spon, London 1993.