Large quantities of ashes made of burning coal are generated in thermal power plants. The waste ash pollutes the environment and presents a risk to public health. “Promobet” will use this ash as raw material for manufacturing porous concrete slabs (the ash will replace some of the cement). The slabs will be used to pave parking lots and gravel paths, and to protect against flooding occurring in urban environments because of rain. This innovation, based on circular economy principles, could have a broad application in the construction industry.