The construction industry, responsible for 9% of global CO2 emissions and 40% of extracted natural resources, faces the challenge of reducing Greenhouse Gas (CH4, N20, fluorinated gases, and CO2 dominant in the civil sector) emissions and managing waste sustainably. To address these challenges, a digital design for manufacturing methodology is proposed, which combines gradient-based topology optimization (TO) with additive manufacturing (AM) for cementitious structural design, leveraging the advantages of complex and non-traditional optimized forms. The methodology entails initially creating a finite element (FE) simulation for TO to minimize compliance within the three-dimensional design domain, taking into account volume workspace and other AM constraints. Following this, the optimized design is converted into a CAD model, and a CAM script is generated in G-Code language. Subsequently, the design is executed through a 3D Concrete Printing (3DCP) system, thereby integrating CAD-CAE-CAM technologies. The research evaluates the potential for mass reduction through TO structures and carbon dioxide emissions of 3DCP compared to traditional methods, emphasizing the potential of digital fabrication for eco-efficient construction. The observed margin highlights promising opportunities for the optimization and implementation of sustainable practices in the field of civil engineering and construction. Copyright (c) 2024 The Authors. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)