Performance and Techno-Economic Feasibility Analysis of Controlled Mechanical Melting Machine for Upcycling Plastic Waste into Sustainable Paving Blocks

Plastic waste management is an urgent global challenge, driving the need for innovation in the circular economy, particularly in the construction sector. This study aims to analyze the performance and techno-economic feasibility of the Controlled Mechanical Melting Machine (CM3) developed for the upcycling of plastic waste into paving blocks. The research method applied systematic engineering experiments and material testing, starting from the identification of dominant plastic waste (PP, HDPE, PET) in East Nusa Tenggara (NTT), the design and fabrication of the CM3 prototype, thermal performance testing, to the production and quality evaluation of paving blocks. The machine performance test results showed that CM3 was able to melt PP plastic with the highest efficiency (time to reach 200°C: 8–10 minutes, fuel consumption: 1.4–1.6 L/cycle). Upcycled paving blocks with a composition of 30–50% PP plastic meet technical standards for non-structural applications, with an average compressive strength of 7.16 MPa and very low water absorption (1.2%) compared to cement paving blocks (6–8%). Financial feasibility analysis reveals a highly attractive business potential with a Break-Even Point (BEP) of 6.5 months, a Return on Investment (ROI) of 452% over 3 years, and a positive Net Present Value (NPV) > IDR 100 million, despite challenges such as premium pricing and limited market adoption. This study concludes that CM3 technology is technically and financially viable as a small-to-medium-scale upcycling solution, directly contributing to plastic waste reduction and the achievement of Sustainable Development Goals (SDGs), particularly SDGs 11, 12, and 9.