3D printing of ordinary Portland cement with waste wood derived biochar obtained from gasification

This research aims to use a circular economy approach for the incorporation of biochar powder from wood biomass gasification (at 0, 5, 10, 15 and 20 wt%) in combination with ordinary portland cement and additive manufacturing (3D printing), specifically using direct ink writing technique. This technique can be used both at large scale and low cost. The importance of this investigation lies in the incorporation of a worldwide large scale waste, biochar, into 3D printing, which could opens up sustainable options for fabrication. A number of four formulations were developed, wherefrom only one was suitable for the 3D printing process, which was attributed to the formulation stability in preserving the shape, and to the surface finishing of the printed pieces as well. For compression tests, cylindrical samples were printed and further evaluated to analyze the process and the waste effect on strength. Additional shapes were built with the same technology to evaluate the limitations of the method. The microstructure of all these formulations has been evaluated using X-ray diffraction and scanning electron microscopy, founding that only the formulation with 10 wt% of biochart was feasible to be made with the direct ink writing technique. Weibull statistics was also included to analyze the variablility of the compression results.