Mechanical Properties of Hybrid Steel-Polypropylene Fiber Reinforced High Strength Concrete Exposed to Various Temperatures

• Published in: Fibers 2022-06, Vol.10 (6), p.53
• Main Authors: Tawfik, Maged, El-said, Amr, Deifalla, Ahmed, Awad, Ahmed
• Format: Article
• Language: English
• Subjects: Cement; Composition; Compressive strength; Concrete; Concrete mixing; Crack initiation; Crack propagation; Cracking; Dynamic testing; Fiber reinforced concretes; Fiber reinforced polymers; Fibers; Flexural strength; High strength concrete; High strength concretes; High temperature; Investigations; Materials; Mechanical properties; Mixtures; Polypropylene; polypropylene fiber; Polyvinyl alcohol; Reinforced concrete; Reinforcing steels; Room temperature; Spalling; steel fiber; Temperature; Tensile strength; Testing
• ISSN: 2079-6439; 2079-6439
• DOI: 10.3390/fib10060053

Combining different types of fibers inside a concrete mixture was revealed to improve the strength properties of cementitious matrices by monitoring crack initiation and propagation. The contribution of hybrid fibers needs to be thoroughly investigated, taking into consideration a variety of parameters such as fibers type and content. In this paper, the impact of integrating hybrid steel-polypropylene fibers on the mechanical properties of the concrete mixture was investigated. Hybrid fiber-reinforced high-strength concrete mixtures were tested for compressive strength, tensile strength, and flexural strength. According to the results of the experiments, the addition of hybrid fibers to the concrete mixture improved the mechanical properties significantly, more than adding just one type of fiber for specimens exposed to room temperature. Using hybrid fibers in the concrete mixture increased compressive, tensile, and flexural strength by approximately 50%, 53%, and 46%, respectively, over just using one type of fiber. Furthermore, results showed that including hybrid fibers into the concrete mixture increased residual compressive strength for specimens exposed to high temperatures. When exposed to temperatures of 200 °C, 400 °C, and 600 °C, the hybrid fiber reinforced concrete specimens maintained 87%, 65%, and 42% of their initial compressive strength, respectively. In comparison, the control specimens, which were devoid of fibers, would be unable to tolerate temperatures beyond 200 °C, and an explosive thermal spalling occurred during the heating process.