A process for making a layered multi-material structural element having controlled mechanical failure characteristics. The process includes the steps of: supplying a cementitious layer and forming a polymer layer on the cementitious layer by additive manufacture such that the polymer layer has a first thickness and the cementitious layer has a second thickness, wherein the polymer layer comprises a polymer and the cementitious layer comprises a cementitious material; and allowing the polymer from the polymer layer to suffuse into the cementitious layer for a period of time to obtain a suffused zone in the cementitious layer such that the suffused zone has a third thickness that is less than half the second thickness.