Nowadays, the concept of new materials are changed in a daily basis. The knowledge of such kind of materials, especially composite materials, has become mandatory since our energy matrix is changing. Polymer concrete appear in this section as a new material with excellent mechanical and electrical properties. Polymer concrete is a concrete like material but instead of concrete a polymer resin is used as matrix. In comparison to ordinary concrete, polymer concrete exhibit excellent compressive, flexural and fracture properties. Also, polymer concrete, as a composite material, can be reinforced with synthetic fibers like glass and carbon, as well as natural fibers, such as coir, sugar cane bagasse, piassava, sisal, banana and curauá. These reinforcements can improve polymer concrete to values even higher than unreinforced.