Abstract: A method of rolling a plastically deformable material which behaves as a single phase and which is deformed plastically when subject to deformation forces, which material comprises from 40% to 70% by weight of hydraulic cement and/or fly-ash particles A of from 0.5 to 100 .mu.m, silica particles B of from 50 .ANG. to 0.5 .mu.m (which are at least one order of magnitude smaller than the cement/fly-ash particles A), a surface-active dispersing system present in an amount sufficient to impart to the composite material a plastic consistency in a stress field of up to 200 kg/cm sq., and from 7% to 20% by weight water; the silica particles B being homogeneously arranged in the voids between the densely packed cement/fly-ash particles A, and the amount of water substantially corresponding to the amount necessary to fill the voids between the solid particles of the composite material.