Coconut Fiber and Marble Powder as Alternative Aggregates in Geopolymer Concretes: Evidence of Mechanical Performance and Durability - Review

This systematic review investigated the use of coconut fiber and marble powder as alternative aggregates in geopolymer concretes, focusing on mechanical performance and durability. A total of 75 documents were analyzed. Of the total documents analyzed, 10 patents and 10 systematic review articles were excluded for not meeting the established methodological criteria. The patents were discarded for not presenting experimental data related to the properties of the composites as a substitute for cement. In turn, the review articles were excluded for not providing primary results, which would make consistent comparative analyses unfeasible. 55 publications (including articles, dissertations, and theses) remained at the end. This survey was conducted during the months of July, August, September, October, and November 2025, covering publications between 2010 and 2025, using databases such as Scopus, Web of Science, SciELO, and Google Scholar. The results indicate that substitutions between 30% and 40% promote significant improvements in compressive strength, tensile strength, and chemical durability, especially when combined with alkaline activators such as NaOH and Na₂SiO₃. The presence of CASH gel and siloxane bonds was recurrent in the studies with the best performance. It is concluded that the use of these residues represents a viable and sustainable alternative for the construction industry, with the potential to reduce environmental impacts and promote the circular economy.