Optical fiber sensors for the detection of chloride in concrete structures

• Grant number: 02/02210-8
• Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE
• Start date: May 01, 2003
• End date: December 31, 2003
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Claudio Oliveira Egalon
• Grantee: Claudio Oliveira Egalon
• Company: C O Egalon Consultoria - ME
• City: São José dos Campos

Abstract

The company intends to develop, in collaboration with the Chemistry Department of the Paulista State University (Unesp), in Araraquara, a new fiber optic sensor for determining the presence and concentration of chloride ions in concrete structures. The sensor will have a spatial resolution of up to 5 millimeters and will provide a reliable form of determining the concentration of chloride ions in a concrete structure, indicating the moment at which that structure should be repaired. In this way, it may even forewarn of its collapse on account of corrosion caused by chloride in the metal framework of the structure. The main cause of this corrosion is the diffusion of chloride ions within the structure. These ions occur in sea water and in the chemical materials used to melt ice (de-icing agents) formed on bridges and roads in cold regions. The proposed sensor consists of an optical fiber the whole length of which is entirely sensitive to chloride ions, forming what is known as a distributed sensor. The sensor can be inserted into the concrete structure to detect the incursion of these ions. It consists of a glass nucleus and a covering made from a fluorescent material, the spectroscopic properties of which are modified in the presence of chloride ions enabling the device to generate a diagnosis swiftly. (AU)