Hybridization and cost-performance analysis of waste tire steel fibers into high-volume powdered scoria rocks-based ultra-high performance concrete

مقال فى مجلة

2023

تم النشر فى: https://doi.org/10.1016/j.jobe.2023.106568

Recycling waste materials into valuable products has become commonplace in everyday life, particularly in the construction sector. This study investigates the utilization of recycled tire steel fibers (RTSF), obtained from recycled waste tires through a conventional recycling technique of shredding and extraction, in the production of ultra-high performance concrete (UHPC). Two RTSF (RTSF-D and RTSF-R) samples were procured from two different sources, and their performance was assessed in the UHPC mix. A quaternary mixture of cement, silica fume, fly ash, and high-volume natural pozzolan prepared from ground scoria rocks was prepared to formulate the cementitious matrix of the UHPC mix. It should be noted that both types of fibers were used together to develop an UHPC mix through constructive hybridization that summed the positive contributions of each fraction from the two sources. From these perspectives, the optimal hybrid configuration of the two types of fibers was suggested and investigated. Four contents of recycled fibers at 1.3, 1.5, 1.9, and 2.5% (volume-based) were investigated. To determine the material's compressive, flexural, and tensile properties, various tests were performed, including a modified mini-slump flow test. An established image analysis technique was conducted to correlate the number of fibers per cross-sectional area of the prism sample to its flexural properties. A good correlation could be obtained. The incorporation of high-volume scoria rock powder supports the sustainability approach as a low-carbon material for low-carbon footprint composites. The performance of the mixture with expensive synthetic straight microfibers was compared to the mixtures with different RTSF for cost-performance-balance analysis. A peak stress in flexure testing of 20 ± 4 MPa could be obtained by using 1.3% of synthetic fibers at a total cost of 122.4 US $/m3 or 2.5% of hybrid recycled fibers (RTSF-50D-50-R) at a cost of 76.10 US $/m3. Accordingly, the analysis becomes feasible when reasonable performance criteria are defined for benchmarking.

• اسم الناشر: Journal of Building Engineering