Selection of waste plastics for incorporation in agro-waste as sustainable building construction materials concerning circular economy: an integrated MCDM approach

The recycling of waste plastics has been recognized as an enticing approach towards the circular economy. The post-consumer plastic products with the incorporation of agro-industrial waste were utilized for the advancement of value-added composites for structural applications. The properties of the composites, namely density, water absorption, compressive strength, flexural strength and abrasive wear, were found to influence by the type of plastics which increases the complexity in the material selection. The research proposed an integrated Analytic Hierarchy Process—Weighted Aggregated Sum Product Assessment (AHP-WASPAS) mathematical model for ranking the composites. The research identified the amalgamation of 15 wt % of rice husk ash and 15 wt % of sand with 70 wt % of polyetheretherketone (PEEK) as a suitable composite for structural applications having minimum abrasive wear and water absorption of 0.0937 cm³ and 0.05059%, respectively. The maximum density, flexural strength and compressive strength were found to be 1.5116 g/cm³, 6.564 MPa and 32.7933 MPa, respectively. Spearman's rank correlation coefficient (SRCC) between the proposed AHP-WASPAS model, and AHP-Weighted Sum Method (WSM), AHP-Technique for Order Performance by Similarity to Ideal Solution (TOPSIS), AHP-COmplex PRoportional ASsessment (COPRAS), AHP-Multi-Objective Optimization on the basis of Ratio Analysis (MOORA), AHP-Multi-Attributive Border Approximation area Comparison (MABAC) and AHP-Additive Ratio Assessment (ARAS) was in the range of 0.7854–1. The sensitivity analyses have observed that the ranking is influenced by the changes in criteria weights includes, density, water absorption, compressive strength, flexural strength and abrasive wear. Moreover, the rankings are unaffected by the parameter lambda (λ) in the WASPAS method. The research has verified the feasibility of waste plastics and agro-industrial waste as innovative materials. Moreover, the proposed mathematical model is reliable and enhances the material selection process in the development of composites.