The increasing demand for aggregates in the construction sector of Vietnam, along with the depletion of natural sand resources, highlights the urgency to explore alternative materials. The scarcity of natural sand resources not only impacts the economic and technical aspects of concrete materials but also emphasizes the need to investigate sustainable solutions. Concurrently, the expanding energy industry in the region necessitates comprehensive research, treatment, and recycling of abundant coal ashes (A mixture of fly ash and bottom ash) generated by thermal power plants. The utilization of coal ashes, specifically fly ash and bottom ash, as substitutes for natural aggregates in concrete presents compelling academic and practical implications. This study aims to examine the feasibility of integrating coal ashes from thermal power plants into semi-dry concrete mixtures for the production of precast hollow wall panels using extrusion technology. Experimental findings indicate that replacing 20% of natural aggregates with coal ashes leads to a significant enhancement in the concrete mixture’s strength by up to 15%. Conversely, complete substitution of natural aggregates with coal ashes results in a notable reduction in the concrete unit weight by a maximum of 20%, accompanied by a substantial increase in water absorption by up to 50%. Notably, the concrete mixture incorporating up to 100% coal ashes instead of natural aggregates meets the prescribed strength requirements outlined in TCVN 11524:2016 for precast concrete hollow wall panels manufactured using extrusion technology. This research not only addresses the scarcity of natural sand but also provides a sustainable solution for managing coal ashes from thermal power plants.