Trends in the Addition of PET and Natural Fibers to the Concrete- Steel Reinforcement System

Due to the nature of the aggregates used in the manufacture of concrete and therefore of the concrete- steel reinforcement system, as well as its growing demand, a negative environmental impact has been caused on the planet. Therefore, at present green alternatives are sought that can reduce the negative impact of the construction industry particularly concrete, some of these alternatives with greater positive impact are: the addition of natural fibers of vegetable origin and the addition of polymers such as recycled Polyethylene Terephthalate (PET), because both materials abound on the planet, they are easy to obtain, and positively impact the environment by reusing them, reducing the use of raw material and energy invested in the elaboration of concrete, which in turn cause the increase in Greenhouse Gases (GHG). Therefore, from this work of review of the state of the art and published trends involving the use of PET and natural fibers in concrete, the effect that the addition of these fibers has on the properties of the concrete-reinforcing steel system, and its impact on the construction industry, was determined. The effect on mechanical properties was mainly reviewed, however, recent studies show that electrochemical properties such as the susceptibility to corrosion of the reinforcing steel embedded in the concrete are also affected, because the presence of oxides on the reinforcing steel causes cracking, weakening the structures, causing a sudden failure of them. However, it is known that this corrosion process mainly affects structures exposed to saline environments such as bridge piles immersed in the sea. Therefore, the study of the concrete-reinforcing steel system and its modification through the addition of natural fibers or polymers partially replacing natural aggregates such as gravel and sand remains of the utmost importance, in order to reduce on the one hand, the environmental impact caused by the exploitation of the natural mantles from which the aggregates are obtained and on the other hand increase the life time of the concrete-reinforcing steel system. This approach is promising especially if one takes into account the results in the literature, which positively point to the addition of PET and natural fibers, since it has been determined that they increase some mechanical and electrochemical properties depending on the form and quantity in which it is incorporated into the concrete mixture.