PSI - Issue 81

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ScienceDirect

Procedia Structural Integrity 81 (2026) 360–366

© 2026 The Authors. Copy from the contract: Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of DMDP 2025 organizers Keywords: high strength concrete, silica fume, polypropylene fiber, strength, impact resistance, long-term effect. Abstract The long-term strength and impact resistance of high-strength fiber-reinforced concrete were assessed in the paper. The study aims to determine the effect of intensive strength building on the long-term behavior of high-strength fiber-reinforced concrete. Long-term effects are analyzed by testing concrete samples with cement content 300, 350 and 400 kg/m 3 after 28 and 360 days. It was observed that the use of mineral additives creates a reserve for improving properties in the long term. The high-strength concrete demonstrates an increase of compressive strength by 7.1 – 19.2% compared to the strength after 28 days. At the same time, the further increase in concrete strength decreases. The impact strength of high strength concretes without fibers after 360 days increases by 1.9 – 2.1 times compared to the impact strength of concretes after 28 days. The impact resistance of high strength fiber reinforced concretes, characterized failure, after 360 days increases by 1.07 – 1.09 times compared to that of fiber reinforced concretes after 28 days. 1. Introduction Concrete is the most widely used construction material in the world. The challenges of the 20th century in building construction and bridge engineering led to progress in improving the properties of concrete, resulting in the development of high-strength concrete (HSC) and ultra-high-performance concrete (UHPC). These types of concrete are characterized by improved rheological and mechanical properties, as well as enhanced durability compared to conventional concrete (Chiadighikaobi et al. (2024); Wang et al. (2024); Sanytskyi 1 et al. (2024)). Whereas, structures based on traditional concrete lose their properties during long-term service and require reinforcement and restoration (Burchenya et al. (2025); Rybak et al. (2024)). The classification of HSC is based on its 28-day compressive strength, which is used in structural design. However, the minimum compressive strength required for HSC varies according to the standards of different countries (Ho and Huynh (2023)). Thus, HSC is characterized by a 28-day compressive strength of 60 MPa or higher according to FIB/CIB specifications. The ACI 363 Committee defines HSC as concrete with a 28-day compressive strength of 55 MPa or higher. According to the European Union standard EN 206-1, HSC corresponds to strength class C50/60 and above. The advantages of using HSC include reduced material consumption, lower transportation costs, and decreased structural loads due to the reduction in the thickness of structural elements and the degree of reinforcement (Gedam and Bhandari (2016); Malhotra and Zhang (2000)). On the other hand, the excellent properties of HSC are associated with increased Portland cement consumption, which results in high cost, energy intensity, and environmental impact. Moreover, the VIII International Conference “In - service Damage of Materials: Diagnostics and Prediction“ (DMDP 2025) Research of long-term properties of high strength fiber-reinforced concrete Nazar Sydor *, Uliana Marushchak, Serhii Braichenko, Ihor Margal Lviv Polytechnic National University, S. Bandery str. 12, 79013 Lviv, Ukraine

* Corresponding author. Tel.: +38 (032) 258-25-41. E-mail address: nazar.i.sydor@lpnu.ua

2452-3216 © 2026 The Authors. Copy from the contract: Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of DMDP 2025 organizers 10.1016/j.prostr.2026.03.062