Abstract: The invention relates to an admixture for a cementitious material suitable to influence the rheological properties of the cementitious material. The admixture includes a compound having a backbone chain provided with at least one first functionality and at least one second functionality. The at least one first functionality is adapted to adsorb to the cement particles of the cementitious material. The at least one second functionality is adapted to respond to an external trigger signal of an electric field, a magnetic field or an electromagnetic field, thereby influencing the rheological properties of the cementitious material. The rheological properties are influenced by influencing the interaction of the at least one first functionality with the cement particles and/or by influencing the interparticle interaction between the cement particles. The invention further relates to a cementitious material including such admixture.

Abstract: The invention relates to a method for layer-by-layer deposition of concrete by providing extrudable concrete. A first flow comprising a binder material and water and a second flow comprising a carrier material, an additional component and water are mixed in a static mixer to form a third flow of extrudable concrete. The material of the second flow has a shorter initial setting time than the material of the first flow. The first flow has a first viscosity V1 and the second flow has a second viscosity V2 so that the ratio V1/V2 ranges between 1/40 and 40. The third flow has a viscosity larger than the viscosity of the first flow and the second flow and a yield stress larger than the yield stress of the first flow and the second flow. The material of the third flow has an initial setting time shorter than initial setting time of the first flow. The invention further relates to a system to extrude concrete, in particular for layer-by-layer deposition of concrete.

Abstract: The invention relates to an admixture for a cementitious material suitable to influence the rheological properties of the cementitious material. The admixture comprises a compound having a backbone chain provided with at least one first functionality and at least one second functionality. The at least one first functionality is adapted to adsorb to the cement particles of the cementitious material. The at least one second functionality is adapted to respond to an external trigger signal of an electric field, a magnetic field or an electromagnetic field, thereby influencing the rheological properties of the cementitious material. The rheological properties are influenced by influencing the interaction of the at least one first functionality with the cement particles and/or by influencing the interparticle interaction between the cement particles. The invention further relates to a cementitious material comprising such admixture.