Strength of Concrete in Slabs, Investigates along Direction of Concreting
Author(s)
Bohdan Stawiski
Affiliation(s)
Institute of Building Engineering, Wroclaw University of Technology Wybrzeze Wyspianskiego, Wroclaw, Poland.
Institute of Building Engineering, Wroclaw University of Technology Wybrzeze Wyspianskiego, Wroclaw, Poland.
ABSTRACT
In theory of concrete it is assumed that concrete composites are isotropic 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 [1-3].
In theory of concrete it is assumed that concrete composites are isotropic 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 [1-3].
Cite this paper
B. Stawiski, "Strength of Concrete in Slabs, Investigates along Direction of Concreting," Open Journal of Civil Engineering, Vol. 2 No. 1, 2012, pp. 22-26. doi: 10.4236/ojce.2012.21004.
B. Stawiski, "Strength of Concrete in Slabs, Investigates along Direction of Concreting," Open Journal of Civil Engineering, Vol. 2 No. 1, 2012, pp. 22-26. doi: 10.4236/ojce.2012.21004.
References
[1] T. Gudra and B. Stawiski, “Non-Destructive Strength Characterization of Concrete Using Surface Waves,” NDT&E International, Vol. 33, No. 1, 2000, pp. 1-6. doi:10.1016/S0963-8695(99)00028-6 [2] B. Stawiski and M. Stawiski, “Tests of Directional Characteristics of Ultrasonic Probes with Geometrically De- fined Waveguides (in Czech),” NDT Welding Bulletin, Vol. 10, 2000, pp. 17-19. [3] V. Dzenis, “Application of Ultrasonic Transducers with Point Contact in Nondestructive Testing (in Russian),” Zinatne Publishing House, Riga, 1987. [4] N. Greig, “Concrete Core Strenght Testing,” Concrete Society, London, 1988. [5] J. Ho?a, K. Schabowicz and B. Stawiski, “Atypical Applications of Ultrasonic Method in Testing of Concrete Structures,” 9th European Conference on NDT.EC NDT, Berlin, 25-29 September 2006, DGZFP Proceedings BB 103-CD. [6] B.Stawiski, “Ultrasonic Testing of Concrete and Mortar Using Point Probes (in Polish),” Wroclaw University of Technology Press, Wroclaw, 2009. [7] J. Ho?a and K. Schabowicz, “New Technique of Nondestructive Assessment of Concrete Strength Using Artificial Intelligence,” NDT&E International, Vol. 38, No. 4, 2005, pp. 251-259. doi:10.1016/j.ndteint.2004.08.002
[1] T. Gudra and B. Stawiski, “Non-Destructive Strength Characterization of Concrete Using Surface Waves,” NDT&E International, Vol. 33, No. 1, 2000, pp. 1-6. doi:10.1016/S0963-8695(99)00028-6 [2] B. Stawiski and M. Stawiski, “Tests of Directional Characteristics of Ultrasonic Probes with Geometrically De- fined Waveguides (in Czech),” NDT Welding Bulletin, Vol. 10, 2000, pp. 17-19. [3] V. Dzenis, “Application of Ultrasonic Transducers with Point Contact in Nondestructive Testing (in Russian),” Zinatne Publishing House, Riga, 1987. [4] N. Greig, “Concrete Core Strenght Testing,” Concrete Society, London, 1988. [5] J. Ho?a, K. Schabowicz and B. Stawiski, “Atypical Applications of Ultrasonic Method in Testing of Concrete Structures,” 9th European Conference on NDT.EC NDT, Berlin, 25-29 September 2006, DGZFP Proceedings BB 103-CD. [6] B.Stawiski, “Ultrasonic Testing of Concrete and Mortar Using Point Probes (in Polish),” Wroclaw University of Technology Press, Wroclaw, 2009. [7] J. Ho?a and K. Schabowicz, “New Technique of Nondestructive Assessment of Concrete Strength Using Artificial Intelligence,” NDT&E International, Vol. 38, No. 4, 2005, pp. 251-259. doi:10.1016/j.ndteint.2004.08.002