Upcycling of composite materials waste into geopolymer-based mortars for applications in the building sector

The possibility to use quartz-composite industrial swarfs as aggregate component in geopolymer-based mortars, to produce materials for upcycling applications, was evaluated. Two different composites (A-type: 90 wt.% quartz, 10 wt.% unsaturated polyester resin; B-type: 60 wt.% quartz, 40 wt.% acrylic resin) were ground to the grainsize < 2 mm, then mixed with metakaolin and potassium silicate (K2SiO3), with the aim to obtain samples with high waste content. The samples produced, with 60–70–80 wt.% waste, show low water absorption, isolated porosity, and good textural relations among components. Mechanical tests indicated very good results at 7 and 28 days, with best data obtained for A-type 70 wt.% waste-bearing sample showing values of 7.5 MPa for flexural strength and 62.5 MPa for compressive strength. The study revealed that quartz-composite waste, usually destined to landfill, could be effectively recycled using geopolymeric binders, postponing therefore their end-of-life. The new materials are very promising for applications in the building sector, e.g., as tiles, slabs or even structural panels and bricks.