The invention provides a process for the production of a cementitious material, comprising mixing cement starting materials, a healing agent and a fibrous reinforcing material, wherein the healing agent comprises bacterial material, and wherein the fibrous reinforcing material comprises a biodegradable polymer, having an average molecular weight selected from the range of 10-1500 kg/mol, and wherein the fibrous material comprises fibers having diameters selected from the range of 5-750 μm, and having lengths selected from the range of 50 μm-150 mm.