Fibre-reinforced composites offer outstanding performance due to the presence of short fibres in the composite. However, the high content of Portland cement used in this type of composites embodied it with high carbon. The production of Portland cement is very energy-intensive and emits a large volume of carbon dioxide into the environment. Therefore, developing a greener binder that totally or at least partially eliminates the use of traditional Portland cement will contribute significantly to reduction in the embodied carbon of the fibre-reinforced composites used for various construction applications. This paper presents the performance of an eco-friendly fibre-reinforced cementitious composite made with sodium-carbonate-activated slag as a binder. The performance of the developed composite was evaluated in terms of its mechanical, shrinkage, permeability properties and non-destructive properties. A microstructural investigation was also carried out to understand the microstructure of the developed composite. The developed composite exhibited a compressive strength, tensile strength and flexural strength of 38.6 MPa, 2.1 MPa and 4.9 MPa, respectively. The corresponding porosity, sorption and chloride ion penetration are 4.9%, 0.18 mm and 458 coulombs, respectively.