The durability of concrete can be assessed based on the quality of the surface layer of concrete, for which there are a few standardized assessment test methods. Usually, the quality of the surface layer of concrete is evaluated based on its air and water permeability. The aim of this experiment was to compare the outputs which provide some methods for determining the permeability of the surface layer of concrete (GWT, ISAT, TPT, the depth of penetration of water under pressure). The measured values using the individual methods of assessing the permeability of the surface layer of concrete very closely correspond.

The mechanical and deformation characteristics of mass concrete are considerably improved by adding long structural fibres. This addition, however, does not always extend the durability of concrete. One of the key factors in the evaluation of durability of fibre concretes is the assessment of permeability of their surface layer using one of the non-destructive methods. In this research, three of these methods were used: two permeation methods with a gaseous medium, TORRENT and CO2 permeability method, and the British ISAT with a liquid medium, on the grounds of their simplicity of application and their possible combinability. The test results show that both TORRENT and ISAT methods can be used to assess the durability of both concrete and fibre concrete with dense aggregate. In the case of concrete containing concrete recyclate, however, the TORRENT method was not effective. Also the method of determining the permeability for CO2 was not suitable for the concrete with concrete recyclate. Even for other concretes this method was too complicated and too dependent on the marginal conditions of the measurement.

Concrete is one of the most common building materials and its durability has been observed with increased attention. It can be said that concrete durability is closely connected with permeability and, generally speaking, the quality of its surface layer. Evaluating the quality of the surface layer of concrete is a rather difficult issue which can be addressed in different ways. The authors of this paper focus on three internationally used methods – TPT, GWT and ISAT. The paper sums up the results of the experiment whose goal was to investigate the influence of concrete composition on the outputs of the above-mentioned methods. For the purposes of the experiment, specimens were made using 9 mixtures which differed only in the amount of cement and plasticiser, i.e. water/cement ratio. The experiment was designed and evaluated using the statistical methodology DOE (Design of Experiment). Next, the paper discusses a new view of statistical evaluation of test results of the methods described above.

Concrete is one of the most common building materials and its durability has been observed with increased attention. It can be said that concrete durability is closely connected with permeability and, generally speaking, the quality of its surface layer. Evaluating the quality of the surface layer of concrete is a rather difficult issue that can be addressed in different ways. The authors of this paper focus on three internationally used methods -TPT, GWT and ISAT. The paper sums up the results of the experiment whose goal was to investigate the influence of concrete composition on the outputs of the above-mentioned methods. For the purposes of the experiment, specimens were made using 9 mixtures, which differed only in the amount of cement and plasticiser, i.e., the water/cement ratio. The experiment was designed and evaluated using the statistical methodology DOE (Design of Experiment). Next, the paper discusses a new view of the statistical evaluation of the test results of the methods described above. Keywords: concrete, permeability, durability, design of experiment Beton je eden najbolj uporabljanih materialov v gradbeni{tvu in njegova zdr`ljivost se prou~uje z veliko pozornostjo. Lahko se re~e, da je zdr`ljivost betona tesno povezana s prepustnostjo, na splo{no s kvaliteto njegove povr{inske plasti. Ocena kvalitete povr{inske plasti betona je precej komplicirano vpra{anje, h kateremu se lahko pristopi na razli~ne na~ine. Avtorji tega~lanka se osredoto~ajo na tri mednarodno priznane metode -TPT, GWT in ISAT.^lanek povzema rezultate preizkusa, katerega cilj je bil prou~evati vpliv sestave betona na rezultate zgoraj omenjenih metod. Za namene preizkusa so bili vzorci izdelani iz 9 me{anic, ki so se razlikovale samo v koli~ini cementa in plastifikatorja, to je razmerja voda/cement. Preizkusi so bili postavljeni in ocenjeni s statisti~no metodologijo DOE (angl. Design of Experiment). Nadalje~lanek obravnava nov pogled na statisti~no oceno rezultatov preizkusa in zgoraj opisanih metod.

The paper focuses on exploring the correlation dependence between the physical-mechanical properties of concretes and alternatively concretes with concrete recyclate and silicate admixtures and the susceptibility of concretes to carbonation. Determining the susceptibility of concretes to carbonation by testing the permeability of their surface layer using the TORRENT, ISAT, or GWT methods is relatively lengthy and requires expensive instrumentation. The first estimate of durability or susceptibility of concretes to carbonation can be easily made on the basis of standard physical-mechanical tests. It seems that the values of volume masses and tensile splitting strengths of concretes could be a good basis for the estimate of their durability.