An international team of researchers is investigating the process that results in the corrosion of steel bars that internally support structures made of reinforced concrete, as well as the solutions that can be undertaken that will avoid, or at least delay, that process.
This research is being spearheaded by an international research group known as Réunion Internationale des Laboratoires et Experts des Matériaux, systèmes de construction et ouvrages (RILEM)1. Based in Paris, France, RILEM’s mission is to advance scientific knowledge related to construction materials, systems, and structures.
It is generally understood that corrosion can be traced to either of the following factors: carbonation and chlorides. In the case of carbonation, it occurs when a concrete covering comes in contact with carbon dioxide, thereby causing a chemical reaction. As for chlorides, material is lost when chlorine compounds attack the steel locally. What RILEM researchers hope to ascertain, however, is how best to mitigate these two corrosion-inducing factors.
“We have put together research carried out previously to know what really happens in the area of concrete-reinforcement contact when chloride corrosion occurs and what are the factors that have a dominant influence on the process,” says Mercedes Sánchez, a researcher from the Universidad de Córdoba (Córdoba, Spain) who has participated in the RILEM study
The project aims to create a catalog of parameters that isolates which corrosion factors should receive lesser priority due to the extensive body of knowledge that already exists for them. Examples of widely studied corrosion factors include the proportion of cement and water, as well as cement types.
At the same time, the study could help materials scientists and engineers determine under-researched factors, such as the properties of steel, the distribution of moisture in concrete, and the existence of small air gaps. For her part, Sánchez is currently working on a project that traps chlorides in concrete and prevents them from corroding steel bars. In another project, her team is looking to incorporate the Internet of Things to perform real-time monitoring of reinforced steel structures.
The results of the RILEM research project can be seen in a paper authored by Sánchez and several of her colleagues.
1 In English, the organization name translates to International Union of Laboratories and Experts in Construction Materials, Systems and Structures.
Source: Universidad de Córdoba, www.uco.es