Incorporating Carbon-Negative Hempcrete in 3D-Printed Eco-Friendly Residential Houses

Abstract The construction industry's heavy reliance on concrete, masonry, and steel has had a detrimental impact on the environment, prompting the development of new materials with reduced environmental footprints. Traditional concrete and steel structures are unsustainable and emit high levels of carbon dioxide. For example, the production of one ton of Portland cement generates about 900 kg of carbon dioxide, which accounts for 88% of the average concrete mix's emissions. To address these sustainability challenges, incorporating hempcrete into 3D printing technology for small-scale buildings and houses is one possible solution. Hempcrete is a construction material made by blending woody hemp shiv or hurd with lime, sand, and water. It can be used to construct walls, floors, and roofs, providing excellent thermal resistance and regulating internal humidity. Hempcrete is a carbon-neutral material that can even store around 35 kg of CO2 per square meter of wall built with a 25 cm thickness over a century, making it a carbon-negative option for the environment. Earthen materials are highly compatible with 3D printing technology, as they require no formwork or mold, and minimize material waste. This paper presents the methodology, experimental investigations, and advantages of using carbon-negative hempcrete as a filler in 3D printed home construction. Hempcrete is casted as a filler in the cells of a 3D printed wall made of “cobcrete”. Furthermore, this study contributes to achieving the United Nations' Sustainable Development Goals through the use of hemp-based materials.