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• Mortar with varying dosages and lengths of amorphous metallic fiber (AMF) were studied. • Flexural performance was enhanced by adding a higher dosage and length of AMFs. • Voids and water absorption increased with the dosage and length of AMFs. • Flexural properties of beams were higher for cured in water than CO 2 -curing. • 0.50% AMF with 20 mm is recommended for producing fiber-reinforced mortar. The present study aims to scrutinize the flexural behavior and engineering properties of beams reinforced with amorphous metallic fiber (AMF) at varying dosages (0%, 0.25%, 0.50%, and 0.75% AMF according to the volume of mortar) and lengths (5 mm, 10 mm, 15 mm, and 20 mm). A total of fourteen mortar mixes, i.e., seven mixes for water curing (immersed in fresh tap water) and seven mixes for carbonation curing (60% relative humidity, 20 °C, and 10% CO 2 concentration) were considered. The load–deflection behavior, flexural strength, pore structures, voids, and water absorption of the beams were investigated. The outcomes were justified with the mix containing 0.5% steel fiber (SF) and a length of approximately 20 mm. The results reveal that the load–deflection behavior and flexural strength were dramatically augmented for the beams with AMF as compared to the control beam (fiber-free beam), and the difference was more pronounced with an increase in both the dosage and the length of the AMF. Greater flexural strength with a lower deflection at failure was registered for the beam with AMF compared to that with SF. The voids and water absorption increased with an increase in the dosage and length of the AMF compared to the control specimen. It was also revealed that the carbonation-cured beams exhibited lower load–deflection behavior and lower flexural strength than those cured in water due to the substantially increased number of voids and greater water absorption driven by the better-connected pores. This study demonstrates that 0.50% AMF with a length of 20 mm can be used in cement-based materials due to the outstanding performance among all mixes. [ABSTRACT FROM AUTHOR]

This study evaluates the mechanical, durability, and residual compressive strength (after being exposed to 20, 120, 250, 400 and 600 °C) of mortar that uses recycled iron powder (RIP) as a fine aggregate. Within this context, mechanical strength, shrinkage, durability, and residual strength tests were performed on mortar made with seven different percentages (0%, 5%, 10%, 15%, 20%, 30% and 50%) of replacement of natural sand (NS) by RIP. It was found that the mechanical strength of mortar increased when replaced with up to 30% NS by RIP. In addition, the increase was 30% for compressive, 18% for tensile, and 47% for flexural strength at 28 days, respectively, compared to the reference mortar (mortar made with 100% NS). Shrinkage was observed for the mortar made with 100% NS, while both shrinkage and expansion occurred in the mortar made with RIP, especially for RIP higher than 5%. Furthermore, significantly lower porosity and capillary water absorption were observed for mortar made with up to 30% RIP, compared to that made with 100% NS, which decreased by 36% for porosity and 48% for water absorption. As the temperature increased, the strength decreased for all mixes, and the drop was more pronounced for the temperatures above 250 °C and 50% RIP. This study demonstrates that up to 30% RIP can be utilized as a fine aggregate in mortar due to its better mechanical and durability performances. [ABSTRACT FROM AUTHOR]