Strength of SCLC recycled springs and fibers concrete subject to high temperatures

• Published in: Structural concrete : journal of the FIB Vol. 23; no. 1; pp. 285 - 299
• Main Authors: Pachideh, Ghasem, Toufigh, Vahab
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY‐VCH Verlag GmbH & Co. KGaA 01.02.2022; Wiley Subscription Services, Inc
• Subjects: Compacting; Compressive strength; Flexural strength; High temperature; high temperatures; Lightweight concretes; Mechanical properties; Modulus of rupture in bending; Polypropylene; polypropylene fiber; recycled spring; self‐compacting lightweight concrete; steel fiber; Steel fibers; Temperature; Tensile strength
• ISSN: 1464-4177; 1751-7648
• DOI: 10.1002/suco.202100183

In this article, the self‐compacting lightweight concretes (SCLC) with different fibers were prepared and exposed to elevated temperatures, and their mechanical properties were investigated. Three types of fibers were steel fibers (SF), polypropylene fibers (PPF), and metal springs with a volume fraction of 0.4%. One hundred and fifty cylindrical specimens were prepared, and the compression, tensile and flexural tests were carried out on them after exposure to high temperatures ranging from 25 to 700°C. The findings indicate that incorporation of steel fibers and springs enhanced the compressive strength of concrete by 20% compared to the control specimen. Meanwhile, the polypropylene fibers increased the tensile strength up to 70% after exposure to the elevated temperatures. The flexural strength of concrete in all specimens was dramatically reduced at the temperature of 700°C. Following an increase in temperature, the bending‐induced strain energy in the specimens containing steel fibers and metal spring increased by 70% and 88% in contrast to the control specimen. Conversely, the strain energy of the specimens containing polypropylene reduced by 70%. For all concrete mixes, the threshold temperature for severe strength loss in the compressive, tensile, and flexural strength tests was 500°C, and the strengths of concrete specimens decreased remarkably at the temperature of 700°C. Finally, the use of metal springs could relatively enhance the mechanical properties of SCLC and reduce the cost.