Concrete is the most environmentally demanding construction material in use worldwide, so evaluating the sustainability performance of concrete is therefore essential. Fiber-Reinforced Concrete (FRC) can diminish the carbon footprint of concrete, being verified by Life Cycle Assessment (LCA). In this systematic review, using the preferred reporting items for systematic reviews and meta-analyses, 69 documents were studied to survey the existing literature on FRC, its LCA methodology and results, and the mechanical performance of the mixes. The results were then presented, and the fibers were characterized, to analyze both the environmental and mechanical performance of the selected research papers using representative indexes, mostly regarding Global Warming Potential (GWP). These indexes showed that the environmental impacts of the FRC mixes could be reduced, even reaching reductions in the GWP of FRC of up to 94 %, without hindering their mechanical performance. FRC sustainability was highly dependent upon the nature and treatment of the used fibers. Thus, steel or synthetic fibers were the most common, yet the most polluting to produce, while some recycled fibers reached high environmental impacts due to the necessary treatments to obtain adequate characteristics, as their non-optimized production procedures can result in up to 7 % increase of GWP of FRC despite of the incorporation of these sustainable raw materials. Nevertheless, those FRC mixes achieved promising LCA results, even diving by half their GWP, when these treatments and procedures were carefully designed. Further development of concrete manufacturing processes and sustainable fiber recovery and characterization are also needed for successful implementation of greener solutions.
