Optimizing gypsum particleboard properties: An orthogonal analysis of pennisetum giganteum and phosphogypsum composites

Gypsum particleboard is attracting attention in the construction industry due to its excellent properties. However, the traditional raw materials for gypsum particleboard are facing a shortage of supply. In this study, we innovatively utilized bulk solid waste Phosphogypsum and Pennisetum giganteum for the first time to manufacture gypsum particleboard. This approach not only effectively addresses the issue of insufficient supply of traditional raw materials for gypsum particleboard but also provides a new pathway for the resource utilization of phosphogypsum. Through an orthogonal experimental design, we focused on optimizing the gypsum particleboard formulation, concentrating on factors such as density, the ratio of Pennisetum giganteum to gypsum (grass-plaster ratio), the ratio of water to gypsum (water-plaster ratio), and the size of the particles. The study determined that the optimal formulation parameters were a density of 1.2 g/cm³, a grass-plaster ratio of 0.20, a water-plaster ratio of 0.25, and a particle mesh number of 14. Under these conditions, the gypsum particleboard exhibited excellent performance, characterized by a static flexural strength of 6.5 MPa, a modulus of elasticity of 2010 MPa, an internal bond strength of 0.4 MPa, a 24-hour water-absorption thickness expansion rate of 2.2%, and an equilibrium moisture content of 1.6%, all meeting the American Society for Testing and Materials (ASTM) Standard D1037. These findings indicate that gypsum particleboards made with Pennisetum giganteum and phosphogypsum can perform comparably to those made with conventional materials. Additionally, a performance prediction model was established using Multiple Linear Regression Analysis (MLRA). The analysis revealed a significant linear relationship between the independent and dependent variables in the model, with the Analysis of Variance (ANOVA) significance levels being less than 0.05, demonstrating statistical significance. This result provides a theoretical basis for the future development of high-performance gypsum particleboard.