Research of the use of alternative raw materials and composite wastes in resin-based composites

Within the scope of this project, fiber-reinforced thermoset resin-based composite materials will be produced using the hand lay-up method, and filler modifications were investigated to minimize process-related defects such as flow disturbances, porosity, and resin insufficiency encountered during production. Although calcium carbonate (CaCO₃) is traditionally widely used to eliminate such defects, a sustainable approach was adopted in this study from both environmental and economic perspectives. Accordingly, various waste-based inorganic fillers were used as alternatives to CaCO₃. Waste materials such as marble cutting waste, trim powder, glass passivation waste, and eggshell powder were prepared in specific particle size ranges (<63 µm) and added to the composite systems at weight ratios of 5-15%. The effects on microstructure, fiber-matrix interfacial interaction, resin flow behavior, porosity level, and mechanical performance were characterized by SEM and tensile/three-point bending/ILSS tests. Regarding both mechanical performance and production process control, the most suitable options were composite plates with 10% trim powder or 10% marble powder additives. Thus, in accordance with the principles of the circular economy, it reduces the consumption of new raw materials, facilitates waste management, and lowers environmental impact. The reuse, without extra energy consumption, and the potential to reduce carbon emissions through recovery and recycling play a significant role in developing sustainable and recyclable environmentally friendly composite systems. This study successfully demonstrated the effects of waste-based additives on mechanical performance and microstructure while reducing process-related defects.