Use of waste polymers in concrete for repair of dam hydraulic surfaces

The durability of a concrete structure is strongly influenced by the inadequate use of materials and by the physical and chemical effects of the environment of its immersion. The immediate consequence is the anticipated necessity of maintenance and repairs, which must have specific characteristics, mainly mechanical and chemical, based on the material of the base or its substratum. In this study different repair materials (RM’s) were analyzed and manufactured to be used on concrete hydraulic surfaces of hydroelectric power plant dams that suffered different types of damage, such as erosion–abrasion and chemical attacks from the reservoir water. Concrete samples were made from polymeric and elastomer materials proceeding from the recycling industry, such as agglutinated low-density polyethylene (LDPE), crushed polyethylene terephthalate (PET) and rubber from useless tires. The contents of each material were 0.5%, 1.0%, 2.5%, 5.0% and 7.5%. Their properties were compared with a reference concrete, without any additions, comparing the compression strength, tensile strength under diametrical compression, underwater erosion–abrasion resistance, microstructure and field application. The samples with 2.5% of addition were the most effective, being LDPE the one which presented better performance.