In this paper a micromechanics-based design is proposed for the development of a material with enhanced ductility and flexural strength combined with low production cost. The composite performance is described by 11 micromechanical properties of the system consisting of cement matrix, fibres and fibre-matrix interface. Most of these properties are defined through laboratory tests. A strain-hardening behaviour with multiple microcracks prior to failure is is the goal for the composite with enhanced ductility. The amount and size of the fibres needed for bridging the microcracks as well as the composition of the cement matrix will be determined in order to achieve this behaviour.