Described are compositions and methods for controlled strength development in a hydratable cementitious material, and more particularly to the use of polymerizable monomer components, which are initiated and activated by a redox pair which are mixed in controlled fashion, for enhancing non-hydration strength within the matrix of the plastic hydratable cementitious material before setting of the cementitious material begins. Exemplary applications include minimizing pressures on formwork for high fluid ready-mix applications, enhancing support and bonding properties for integrated concrete slab work and other sequential applications, or facilitating speedy 3D printing applications, among other unique possibilities.