Evaluating the potential use of recycled glass fibers for the development of gypsum-based composites

The concerns on the recyclability of composites are rising. Finding ways to reuse composite materials is fundamental given their huge availability worldwide. However, the intrinsic characteristics of composite materials make it hard to recover their primary constituents. Therefore, the incorporation of these materials after their typical life span into other applications is of great importance towards their circularity and valorisation. In this paper we evaluate the possibility of recycled fiberglass sheets to be used for the creation of gypsum-based composites, aiming at improving the mechanical properties when compared to conventional gypsum. We benchmark the effect of adding recycled fibers against the use of virgin ones. Neat gypsum plaster was used as the matrix and reinforced with both commercial E-glass and recycled fibers. The addition of recycled fibers into the gypsum matrix modified the material behaviour, preventing a purely brittle behaviour, and increasing the flexural strength by 66 % when 6 wt. % was added. The addition of virgin E-glass fibers not only allows for massive plastic deformation of the composite but also increases its flexural strength by nearly 290 % when a mass fraction of 12 wt. % of E-glass was added.