A luminescent material designed to reveal signs of deterioration in concrete has been developed by researchers from the University of São Paulo's Physics Institute (IF-USP) in Brazil and the University of Leuven in Belgium.

According to the researchers, the new luminescent material allows for a fast, low-cost, in-situ approach for analyzing the condition of concrete — used in the foundations and structures of houses and office buildings, roads, dams and bridges, and assorted other infrastructure projects — revealing the presence of compounds associated with the deterioration of concrete when exposed to ultraviolet (UV) light.

Source: Danilo Mustafa

The new method, which helps to monitor the service life of concrete to ensure the safety of a structure, reportedly avoids having to drill a structure to remove and subsequently take samples of the concrete to a lab.

To avoid this, the researchers created a catalyst based on layered double hydroxide (LDH) — otherwise known as anionic clay — for measuring the degree of deterioration in concrete. Further, the team added trivalent europium (Eu³⁺) to create orange-to-red luminescence.

In the lab, the researchers demonstrated that when the material was exposed to UV light, its luminescence changed color in response to how much carbonate it had absorbed. As such, this approach can be employed to detect deterioration in concrete, wherein the greater the redshift detected, the greater the amount of carbonate present, and, consequently, the more degraded the concrete.

"The main advance is that the material can help determine in real time how the concrete present in a structure is deteriorating and when the structure will require maintenance, without any need for drilling or waiting for laboratory analysis. This contributes to more agile decision-making, facilitates preventive maintenance, and helps avoid accidents that can cost lives and cause considerable economic damage," explained the researchers.

An article detailing the research, "Eu³⁺ doped ZnAl layered double hydroxides as calibrationless, fluorescent sensors for carbonate,” appears in the journal Chemical Communications.