The intrinsic coefficient of concrete permeability subjected to cyclic water freezing

Author(s): Alicja Wieczorek, Dalia Bednarska, Marcin Koniorczyk
Paper category: Proceedings
Book title: Proceedings of the International Conference on Sustainable Materials Systems and Structures (SMSS2019) Durability, Monitoring and Repair of Structures
Editor(s): Ana Baričević, Marija Jelčić Rukavina, Domagoj Damjanović, Maurizio Guadagnini
ISBN: 978-2-35158-217-6
e-ISBN: 978-2-35158-218-3
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 64-71
Total Pages: 813
Language: English

Abstract: The parameters characterizing inner structure of the cement-based materials, such as porosity or permeability, determine risk of degradation of cement matrix due to aggressive environment. The paper concerns the influence of frost degradation on transport properties of water saturated concrete in accelerated durability tests and their resistance to cyclic water freezing. The experimental study is focused on the examination how the frost-induced damage affects the intrinsic coefficient of concrete permeability. The measurements have been performed on concrete specimens with two type of Portland cement (CEM I 42,5N/NA and CEM I 42,5R) with different water-cement ratio (w/c=0.4÷0.5) without air-entraining admixtures. In order to analyse the frost degradation of the material, which is characterized by the permeability evolution (measured by means of Cembureau permeability test), two methods of sample preparation have been proposed. In the first method, the measurements of gas permeability are performed before samples are subjected to repeating freeze-thaw cycles. In this case specimens cut off from the central part of the cylindrical sample have been considered. Subsequently, the discs are placed in the climatic chamber and undergone an assessment of their resistance to frost. Once the assumed number of freezing-thaw cycles is achieved, the oxygen permeability test is conducted again. The analysis of the process of frost destruction in the second proposed procedure is slightly different. In case of the next experimental method, after cyclic water freezing, the concrete cylindrical samples have been cut into smaller specimens and then the oxygen permeability test is conducted. The proposed research procedures, apart from the advantages, are also associated with some restrictions, which are described in detail in the report. The choice of the method is important and influences the obtained results.

Online publication :2019
Publication type : full_text
Public price (Euros) : 00