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This paper study the feasibility of reusing waste iron powder (WIP) in mortar as both natural fine aggregate (NFA) and cement replacement material. Within this context, the physical and mechanical properties of mortar made with five percentage replacements of 0 %, 25 %, 50 %, 75 %, and 100 % for NFA by WIP and 0 %, 2.5 %, 5 %, 7.5 %, and 10 % for cement by fine waste iron powder (FWIP) are studied at 7, 14 and 28 days. Cube, briquette, and prism specimens for compression, tension, and flexural strength, respectively, tests were used. It is found that the workability decreases, and the density of mortar increase with the increased replacement percentage of NFA by WIP. The compressive, tensile, and flexural strength of mortar made with WIP are significantly higher than NFA. The maximum increase in strength of mortar is observed for 75 % WIP, which is 30 % for compressive, 35 % for tensile, and 37 % for flexural strength, respectively, relative to the control at 28 days. Conversely, when FWIP is used as a cement replacement material, all strength decreases with an increase in FWIP. The maximum decrease in strength is observed for 10 % FWIP, which is 40 % for compressive and tensile, and 16 % for flexural strength, accordingly, relative to the control at 28 days. The results presented in this study demonstrate that, to some extent, WIP and FWIP can be used in concrete/mortar production. Successful application of these waste materials may add economical benefit in the production of sustainable building material as well as conserve the natural aggregates.

Fiber-reinforced concrete (FRC) has become one of the most promising construction techniques and repairing materials in recent times for the construction industry. Generally, plain concrete has a very low tensile strength and limited resistance to cracking prior to the ultimate load, which can be mitigated by the incorporation of fiber. Natural fibers have emerged as an appealing sustainable option in the last few decades due to their lower cost, energy savings, and minimized greenhouse effects. Areca fiber is one of the natural fibers that can be sourced from the waste-producing areca nut industry. Hence, this study aims to assess the mechanical, rheological, and micro-structural properties of areca fiber-reinforced concrete (AFRC). For this purpose, areca fiber was used in the concrete mix as a weight percentage of cement. In this regard, 1%, 2%, 3%, and 4% by weight of cement substitutions were investigated. As key findings, 2% areca fiber enhanced the compressive strength of concrete by 2.89% compared to the control specimen (fiber-free concrete). On the other hand, splitting tensile strength increased by 18.16%. In addition, scanning electron microscopy (SEM) images revealed that the cement matrix and fibers are adequately connected at the interfacial level. Energy dispersive X-ray spectroscopy (EDX) test results showed more biodegradable carbon elements in the areca fiber-mixed concrete as well as an effective pozzolanic reaction. The study also exhibited that adding natural areca fiber lowered the fabrication cost by almost 1.5% and eCO2 emissions by 3%. Overall, the findings of this study suggest that AFRC can be used as a possible building material from the standpoint of sustainable construction purposes. [ABSTRACT FROM AUTHOR]

Managing disposable waste surgical face masks and plastic made from polyethylene (PE) resin is a real challenge. Thus, these are considered a great threat to the environment. Generally, surgical face masks are made of microplastic made of polypropylene materials. Both polypropylene and PE are not easily decomposable in the soil. Consequently, the presence of these waste materials can have detrimental effects on terrestrial and aquatic ecosystems, exacerbating the ongoing crisis faced by the animal kingdom and the broader biosphere. Hence, it is imperative to identify alternate and efficient methods for waste management. Given its significant economic importance, the construction industry holds a prominent position among many industries globally. Consequently, waste masks within the construction sector might assume a crucial role in mitigating plastic pollution. Concrete, one of the most widely used construction materials, is being adapted with various waste materials as the partial or complete substitutes for natural constituents, such as cement and aggregates. This study focused on using different percentages of used COVID-19 surgical masks in fiber form and PE as partial replacements of natural coarse aggregates in producing sustainable concrete. Mask fibers were used in concrete production at percentages of 0%, 0.5%, 1%, 1.5%, and 2% of the total volume of concrete. Similarly, PE aggregates replaced the coarse aggregates by volume at 0%, 5%, 10%, and 15% in concrete. The results showed that the strength of concrete reduced as the percentages of mask fiber and PE aggregates increased. However, the strength and crack-bridging capability of mask concrete are still acceptable for some structural and non-structural applications. The results obtained from this research could also help engineers to design sustainable concrete materials with mask fibers. [ABSTRACT FROM AUTHOR]