PSI - Issue 81

Mykhailo Hud et al. / Procedia Structural Integrity 81 (2026) 205–209

209

In addition to assessing the strength properties, an analysis of the water absorption behavior of the specimens was conducted to evaluate the density of the concrete structure and the permeability of its pore system. The lowest water absorption values were obtained for the specimens of Series 3, which contained the highest volume of epoxy resin. Their dry mass was 7.8 kg, increasing only to 7.81 kg after saturation. The minimal difference between these values indicates the development of a dense matrix in which the capillary – pore structure is significantly reduced and partially blocked by the polymer component. Intermediate absorption values were recorded for Series 2, which contained a moderate amount of epoxy resin. The mass of the specimens increased from 8.20 kg in the dry state to 8.25 kg after saturation. These results demonstrate a moderate level of water uptake and suggest partial densification of the structure, although to a much lesser extent than in Series 3. The highest water absorption indicators were observed for Series 1, produced without the use of epoxy resin. The mass of the cubes increased from 8.8 kg before testing to 8.88 kg after saturation. Such high-water absorption is typical of conventional concrete and reflects the presence of a well-developed pore structure that has not undergone modification by polymer additives. 4. Conclusions The results of the experimental investigation indicate that the use of epoxy modifiers in concrete mixtures exerts a complex and ambiguous influence on the development of the material’s physico -mechanical properties. The obtained data demonstrate that partial or complete replacement of water with epoxy resin significantly alters the cement hydration processes and the structuring of the cementitious matrix. This effect is most evident in the reduction of compressive strength: the series with moderate and maximum resin content exhibited strengths of 17.4 MPa and 16.6 MPa, respectively, which is nearly half the value recorded for the conventional concrete series, whose strength reached 30.7 MPa. These findings suggest that an excessive amount of the polymer component disrupts the integrity of the mineral matrix, creates weak zones, and leads to atypical failure mechanisms under loading. At the same time, an opposite trend was observed in the water absorption characteristics. The lowest values were recorded for the series with the highest epoxy resin content, indicating substantial densification of the capillary – pore structure and reduced permeability of the material. By partially filling and blocking pores, the polymer decreases water ingress, which may be critically important for concretes operating under cyclic wetting and freezing conditions. In summary, epoxy modifiers may be considered effective primarily for enhancing the density of concrete, particularly in applications where strength requirements are not the governing factor. However, excessive reduction of water content and increased resin proportion lead to a pronounced decline in mechanical performance. Therefore, the optimisation of polymer modified concrete formulations should be based on achieving a balance between improving water resistance and maintaining an adequate level of strength, which defines the prospects for the practical implementation of such materials in construction. References Brosch F., Reichenbach S., Braun M., Kromoser B. , 2025. Mechanical assessment of epoxy‑bonded timber -concrete-composite shear specimens. Case Studies in Construction Materials 23, e05418 https://doi.org/10.1016/j.cscm.2025.e05418 Kononchuк O., Iasnii V., Lutsyk N., 2022. Prediction of reinforced concrete structures behavior using finite element method. Procedia Structural Integrity 36, 177-181 https://doi.org/10.1016/j.prostr.2022.01.021 Stukhliak P., Martsenyuk V., Totosko O., Stukhlyak D., Didych I., 2024. The use of neural networks for modeling the thermophysical characteristics of epoxy composites treated with electric spark water hammer. CEUR Workshop Proceedings, 3742, 13-24. Stukhliak P., Totosko O., Stukhlyak D., Vynokurova O., Lytvynenko I., 2024. Use of neural networks for modelling the mechanical characteristics of epoxy composites treated with electric spark water hammer. CEUR Workshop Proceedings, 3896, 405 – 418. Wang Y., Zhu Z., Cao R., Xu L., Huang B., 2025. Insights into the properties of pervious concrete modified with polymers and fine aggregate. Case Studies in Construction Materials 22, e04627 https://doi.org/10.1016/j.cscm.2025.e04627 Xia D., Xia P., Hu J., Li X., Zhan Z., 2024. Optimization of mechanical properties of pervious recycled concrete using polypropylene fiber and waterborne epoxy resin. Structures 63, 106372 https://doi.org/10.1016/j.istruc.2024.106372