Technical fibres are the backbone of 3D concrete printing. The STW high modulus fibres are thick, robust fibres with a kidney-shaped cross-section. These properties help to increase the compressive and flexural strength of the concrete. The alkali, acid, solvent and weathering resistance of the fibre can provide long-term stability to the concrete matrix. The flowability of the concrete matrix is improved by adding PAC 251/ 60 dtex, which is essential for the 3D concrete pressure process.