Procedia Engineering 193 ( 2017 ) 35 41
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Evaluation of Concrete Resistance to Freeze-thaw B
4. Conclusions
The paper proposes the concrete freeze-thaw resistance evaluation procedure based on the modification of the method set forth in PN-88/B-06250. The basic procedure in freeze-thaw resistance evaluation is measuring changes in mass of the specimens during freeze-thaw cycles, with the mass gain assumed to be a result of micro-cracks forming in the structure of concrete. It is possible to determine the number of freeze-thaw cycles needed for the critical damage to occur, corresponding to the strength decrease, ǻR=20%. The paper assumes that for ǻR=20%, the
41 Jerzy Wawrzeńczyk and Agnieszka Molendowska / Procedia Engineering 193 ( 2017 ) 35 – 41 critical mass increase ǻm is about 10 g. The authors consider this approach to be better than that provided in the standard, because it allows including the scattering of the results in addition to the mean values. The number of freeze-thaw cycles needed to reach the critical mass gain in the specimens is used to determine the parameters of the Weibull distribution and to develop a damage model for the concrete under freezing. For the adopted probability, it is thus possible to determine how many freeze-thaw cycles the concrete is able to withstand until the critical saturation is reached. The paper includes examples of the analysis performed for two concretes. References [1] C. Korhonen, Effect of high doses of chemical admixtures on the freeze-thaw durability of portland cement concrete, US Army Corps of Engineers, Technical Report ERDC/CRREL TR-025, 2002. [2] J. Walraven, Design for service life: how should it be implemented in future codes, International Conference on Concrete Repair, Rehabilitation and Retrofitting. Proceedings ICCRRR, Cape Town, 2008, pp. 3–10. [3] M. G. Richardson, C. McNally, M. O'Connell, Equivalent concrete performance concept: Durability studies of limestone cement/GGBS concretes, 3 International Conference on the Durability Structures, Queen's University Belfast, 2012. [4] A. Duan, Y. Tian, J-G. Dai, W-L. Jin, A stochastic damage model for evaluating the internal deterioration of concrete due to freeze-thaw action, Materials and Structures. 47 (2014) 1025-1039. [5] P. Qiao, F. Chen F, Cohesive and probabilistic damage analysis of freezing-thawing degradation of concrete, Construction and Building Materials. 47 (2013) 879-887. [6] M. J. Setzer, Action of frost and deicing chemical – basic phenomena and testing. Freeze-thaw durability of concrete. Edited by J. Marchand, M. Pigeon and M. Setzer, E&SPON, London, 1997, pp. 3–22. [7] J.
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