Cementitious biochar compositions and methods of making the same

A cementitious mixture, comprising:

• a hydraulic cement;
• between 4.5% and 30% of a biochar by weight based on a total amount of the hydraulic cement and the biochar;
• between 60% and 85% of an aggregate material by weight based on the hydraulic cement, the biochar, and the aggregate material;
• and
• water, wherein:
• the biochar comprises an ash content between 3 wt % and 30 wt % based on the weight of the biochar,
• the biochar comprises a mean particle size (Dv,50) of between 0.1 μm and 3.0 μm,
• the biochar and the aggregate material are dispersed within the hydraulic cement,
• the cementitious mixture has a water to hydraulic cement ratio between 0.3 and 0.65,
• the cementitious mixture has a slump between 100 mm and 150 mm, and
• the cementitious mixture is capable of curing into a cementitious solid having a compressive strength between 50 MPa and 90 MPa.

A method of preparing a cementitious solid, comprising:

• producing a biochar by fast pyrolysis;
• and
• forming a cementitious mixture by combining
• a hydraulic cement, an aggregate material, and the biochar;
• adding water to obtain a water to hydraulic cement ratio between 0.3 and 0.65;
• and
• mixing the cementitious mixture such that the biochar and the aggregate material are dispersed within the hydraulic cement resulting in a slump between 100 mm and 150 mm, wherein:
• the cementitious mixture contains between 4.5% and 30% of the biochar by weight based on a total amount of the hydraulic cement and the biochar;
• the cementitious mixture contains between 60% and 85% material by weight based on the hydraulic cement, the biochar, and the gate material;
• the biochar comprises an ash content between 3 wt % and 30 wt % based on the weight of the biochar,
• the biochar has a mean particle size (Dv,50) between 0.1 μm and 3.0 μm, and
• the cementitious mixture is capable of curing into the cementitious solid having a compressive strength between 50 MPa and 90 MPa.