The heterogeneity of mechanical properties of concrete in formed constructions horizontally

• Autorzy: Stawiski B.
• Języki publikacji: EN

Abstrakty

EN

In theory of concrete it is assumed that concrete composites are homogeneous on a macro scale. For example, it is assumed that a floor slab's or a beam's strength is identical in all directions and its nonhomogeneity is random. Hence neither calculations of the load-bearing capacity of structural components nor the techniques of investigating concrete in structure in situ take into account to a sufficient degree the fact that the assumption about concrete isotropy is overly optimistic. The present research shows that variation in concrete strength along the direction of concreting has not only a qualitative effect (as is commonly believed), but also a significant quantitative effect. This indicates that concrete is a composite which has not been fully understood yet. The paper presents evaluations of ordinary concrete (OC) homogeneity along component thickness along the direction of concreting. The ultrasonic method and modified exponential heads with a point contact with concrete were used in the investigations .

Słowa kluczowe

EN

ultrasound; concrete; strength; heterogeneity

PL

ultradźwięk; beton; siła; niejednorodność

• Wydawca: Springer ; Wrocław University of Science and Technology
• Czasopismo: Archives of Civil and Mechanical Engineering
• Rocznik: 2012
• Tom: Vol. 12, no. 1
• Strony: 90--94
• Opis fizyczny: Bibliogr. 8 poz., rys., tab., wykr.

Twórcy

autor

Stawiski B.

• Wrocław University of Technology, Wybrzeże Wyspiańskiego 25, 50-370 Wroclaw, Poland

Bibliografia

• [1] T. Gudra, B. Stawiski, Non-destructive strength characterization of concrete using surface waves, NDT&E International 33 (1) (2000) 1–6.
• [2] N. Greig, Concrete core strength testing, Concrete Society Digest no. 9 (1988).
• [3] B. Stawiski, M. Stawiski, Tests of directional characteristics of ultrasonic probes with geometrically defined waveguides, NDT Welding Bulletin 10c (2000) 17–19 (in Czech).
• [4] V. Dzenis, Application of ultrasonic transducers with point contact in nondestructive testing, Zinatne Publishing House, Riga, 1987, p 263 (in Russian).
• [5] V.G. Shevaldykin, A.A. Samokrutov, V.N. Kozlov,Ultrasonic low-frequency shot-pulse transducers with dry point contact. Development and application, in: International Symposium NDT-CE, DGZFP, BAM, Berlin, 2003. http://www.ndt.net/article/ndtce03/papers/v066/v066.htm
• [6] B. Stawiski, Ultrasonic testing of concrete and mortar using point probes, monographs, Wroclaw University of Technology, 2009, pp. 154 (in Polish).
• [7] J. Hoa, K. Schabowicz, B. Stawiski, Atypical applications of ultrasonic method in testing of concrete structures, in: 9th European Conference on NDT.EC NDT, Berlin, 2006, DGZFP Proceedings BB 103-CD.
• [8] PN-EN 13791, Assessment of in-situ compressive strength in structures and precast concrete components.