For the purpose of reducing structural damage against blast loading, fiber reinforced polymers sheet (CFRP, GFRP) can be used to retrofit the RC slabs. In this study, specimen of reinforced concrete slabs with or without retrofitting are modeled numerically. The results show that using high resistant, elastic material such as FRP sheets, are effective in reducing deformation of slabs, but it doesn’ t significantly increase the energy absorption capacity of structure. Using Polyurea (PU) coating with elastoplastic behavior on the FRP sheets, in addition of deformation reducing, will increase the absorption of energy up to 40 percent. In this combination, layer arrangement has an important role, so that if the PU coating is positioned between concrete and hard sheets, its efficiency will be reduced by 30% compared to the previous arrangement. When the reinforcement element is placed in front of the slab, it will increase the energy absorption up to 50 percent compared to the state where it is placed in the back of the slab. It has been also shown that PU alone is not useful and it should be used with stiffeners for better results.