Concrete is the most widespread construction material in civil engineering because of its mechanical properties, durability and versatility. However, its environmental impact is significant, due to the raw materials which constitute it, and its great ecological footprint. A possible solution to limit the energy consumption and the CO₂ emissions during its production and use, stays in the development of more sustainable alternative mixes. Among eco-friendly ones, earth-based concretes, where cement is partially substituted by earth, allow an environmental advantage with respect to conventional concretes, keeping acceptable mechanical properties for smaller structural applications. The paper describes and comments the results of an experimental campaign carried out on samples with matrices of earth and cement, newly doped with carbon microfibers. These construction materials, developed by the authors, are able to exhibit self-monitoring capabilities. Such a multifunctional behavior results particularly effective for monitoring of structures during their service life and after critical events such as earthquakes. The characterization of fracture development occurred through three-points bending tests has been carried out through both electrical measurements and Digital Image Correlation. The influence of the carbon inclusions on the mechanical properties has been also evaluated and discussed.