Vegetal concrete masonry unit and method and system for manufacture thereof

A method for the preparation of a vegetal concrete masonry unit, the method comprising:

• cooking crop residue in a cooker with sodium hydroxide (NaOH) and water to yield crop residue;
• washing the cooked crop residue obtained from the cooker to yield a washed crop residue;
• mixing hydrated lime, Ground Granulated Blast Furnace Slag (GGBFS) having a specific surface area of at least 400 m2/kg, and sodium silicate activator powder for at least 5 minutes in a ribbon blender to constitute a binder;
• intermixing the washed crop residue, the binder and pulverized fuel ash (PFA) together in a pan mixer with water to form an alkali activated homogeneous paste/gel;
• and
• molding the homogenous paste/gel obtained in the intermixing step using a high-pressure hydraulic press capable of delivering a minimum pressure of 2 MPa to form the vegetal concrete masonry unit;
• wherein the crop residue is cooked in a cooker with 0.2 M to 10 M NaOH aqueous solution at 150° C. for a duration of 15 to 45 minutes to improve compatibility between the crop residue and the binder;
• wherein the hydrated lime in the binder wherein at least 85 percent calcium hydroxide and is mixed with GGBFS in a 1:6 to 2:3 ratio;
• and
• wherein the sodium silicate activator is in an amount equal to 2.5-20% of the total mass of the hydrated lime and the GGBFS in the ribbon blender to constitute the binder.