Natural fibres and biopolymers in FRP composites for strengthening concrete structures: A mixed review

Fibre-reinforced polymer (FRP) laminates/sheets have been used to retrofit concrete structures. Increased global awareness of environmental protection needs and recent legislation have propelled researchers to develop more environmentally friendly FRP materials to be used in place of synthetic FRP materials. Through a bibliometric and systematic literature review, this article reports on research on the use of bio-based FRP materials comprising of either natural fibres or biopolymers as external reinforcement for concrete structures. Eighty-seven experi- mental studies retrieved from Scopus and Google scholar databases were considered for this study. Analysis and visualization of research output per year and region, re-occurring keywords, co-authorship network and docu- ment co-citation networks are presented. The effects of various bio-based FRP materials used to strengthen various concrete members considering different FRP fabrication techniques and FRP configurations are pre- sented. The study revealed that bio-based FRPs could effectively strengthen concrete beams and columns. Durability, cost and sustainability of these materials are also discussed. The paper also outlines pathways for further research and considerations for developing design frameworks