Engineered gypsum composites with superabsorbent-polymers and natural/recycled fibre reinforcement: Multi-scale performance and validation

This study explores the impact of potassium polyacrylate (KPA), tyre fibres (T), and wood fibres (W) on a plaster-based composite’s key mechanical, physical, and thermal properties. Modifications to the control sample yielded enhanced flexural strength in most formulations, showcasing additive reinforcement potential (up to 4.87 MPa). Tailored impact resistance was achieved, with reinforced samples exhibiting generally lower resistance. Significantly, specific combinations of KPA, T, and W (E-0.7-KPA-T-20% and E-0.7-KPA-W-20%) achieved remarkably low thermal conductivities, reaching values as low as 137.77 mW/(m·K) in the best-performing formulations. This suggests strong insulation potential within the scope of this study. Additionally, formulations, particularly those with wood fibres, exhibited reduced apparent density compared to the control sample (>10%), suggesting potential for lightweight materials. SEM imaging, XRD and DSC analysis were conducted to check the materials’ behaviour and provide an understanding on the effect of the modifications. This study highlights KPA's ability to further enhance the beneficial effects of other additives, leading to significant decreases in both density and thermal conductivity. These findings demonstrate the potential for tailoring material properties through strategic additive selection, paving the way for developing advanced materials with tailored functionalities for various applications.