The construction industry and waste polymers are major contributors to the carbon footprint, exacerbating climate change. Traditional building materials, especially cement, emit significant carbon dioxide. Furthermore, the disposal of over 20 billion diapers annually in landfills causes environmental harm due to the slow degradation of waste polymers, lasting up to 500 years. A study investigates a sustainable solution using used diapers, fly ash, and sodium polyacrylate through green chemistry. This approach transforms these materials into an eco-friendly construction substance named ‘polycrete’. Sodium polyacrylates are de-crosslinked to form a gel that expands substantially, increasing in volume by about 400%. The raw material consists of the gel (25%), fly ash (65%), lime (6%), and silica (4%), molded into bricks and cured at room temperature for seven days. These bricks display impressive compressive strength, exceeding 10 MPa, equivalent to 50% of traditional concrete bricks with seven days of curing. This study also focuses on the variation of the compressive strength obtained by adding silica to the mixture. The bricks were suitable for various non-load-bearing construction applications. This study highlights a promising approach to creating sustainable construction materials while addressing waste pollution.