The world’s plastic bag problem adversely impacts the environment daily. Plastic bags decompose after years, and some may take centuries, leading to pollution. Society relies on plastic bags for every task, which causes many problems for humans and aquatic life. Focusing on Sustainable Development Goal 12 (SDG 12), this research used waste plastic bags melted in a boilery to develop plastocrete to cast plastocrete paving blocks and roofing tiles. Compressive and split tensile strength tests were performed on plastocrete paving blocks, while a thermal insulation test was performed on roofing tiles in the Concrete Lab of our Department. The compressive strength test on plastocrete showed that it can easily replace concrete pavement blocks after giving good compressive strengths compared with concrete blocks. Being very low in tensile strength, plastocrete is not recommended for flexure members. The thermal insulation test results indicate that using plastic bags as roofing tiles decreases thermal conductivity compared with a controlled reinforced slab. Hence, it is concluded that plastocrete will help reduce pollution in the terrestrial and aquatic environment and can be an effective waste disposal solution. The plastocrete-led paving blocks and roofing tiles not only help economically but also help preserve nature and the environment from land pollution.

This research examines the mechanical enhancement of earthen mortar through the combined use of cow dung (CD) and sawdust (SD) as biodegradable stabilisers, aiming to develop a structurally reliable and low-carbon alternative to conventional binders. Stabiliser contents ranging from 2.5% to 10% were incorporated into a locally sourced clayey soil, followed by a comprehensive evaluation of fresh and hardened density, unconfined compressive strength, split-tensile strength, flexural capacity, and derived undrained shear strength. The test results show that the CD-SD blend significantly improves mechanical performance, with compressive strength increasing by approximately 40% at 7.5% stabiliser content and tensile strength, and nearly doubling at 10% addition. Flexural strength exhibited a parallel rise of 68% relative to the untreated mix. These improvements are linked to the formation of cementitious reaction products from cow-dung ash, enhanced particle adhesion, and the micro-reinforcing role of SD fibres, which collectively reduce crack formation and increase the material’s resistance to tensile and bending stresses. Concurrently, fresh and hardened densities decreased by 14–21%, producing a lightweight composite without compromising structural reliability. The findings identify an optimum stabiliser range of 7.5–10%, balancing strength enhancement with desirable density reduction. Overall, the study confirms that CD-SD stabilisation provides a feasible, cost-effective, and environmentally responsible approach for improving earthen mortars, offering substantial potential for sustainable construction in regions where low-carbon and locally available materials are essential.