The construction sector faces the urgent challenge of reducing the environmental impact associated with cement production. In response, biodegradable materials such as agave fibers and biochar have attracted growing interest as sustainable alternatives for improving concrete performance. This systematic review is based on an initial identification of 2250 records retrieved from the Web of Science and Scopus databases. After screening 1088 studies and applying the PRISMA 2020 methodology, a total of 45 scientific articles published between 2014 and 2025 were selected for detailed analysis. The literature on the use of agave fibers and biochar in concrete is diverse and challenging to compare due to variations in methods and dosages. The study is based on a comparative and critical analysis of the available experimental evidence to identify and propose optimal dosage ranges for using agave fibers (Agave sisalana and Americana) and biochar (produced from organic waste) that maximize mechanical improvements in concrete without compromising its structural integrity. The results indicate that agave fibers (0.25%–1.0% by volume, with lengths close to 25 mm), especially when subjected to thermal or chemical treatments, improve flexural behavior, while biochar (1%–5% relative to the weight of cement) increases compressive strength. However, the analysis identifies significant gaps in knowledge regarding the standardization of treatments, their large‐scale use in real projects, and the lack of regulations. There is ample scope for further research into the use of agave fibers and, above all, biochar in concrete elements to promote sustainable construction technologies.
González et al. (Thu,) studied this question.