A biocidal structural barrier of a raw concrete or a structure made of concrete is provided containing a specific insecticidal biocide product and/or a repellent that has been incorporated throughout the mass. The invention is particularly suitable for the building and construction sector and more particularly for concrete structures located close to the soil or in the soil (slab, foundations, buried walls, prefabricated concrete blocks, etc.). The preferred insecticide for protection against termites is chlorfenapyr.