A novel material enables the assessment of concrete deterioration

The University of São Paulo's Physics Institute (IF-USP) in Brazil, in collaboration with counterparts from the University of Leuven in Belgium and researchers from the University of Kiel in Germany, have engineered a luminescent substance to address the need for prompt and cost-effective on-site analysis of the concrete’s deterioration without the need of transporting samples to a lab.

Concrete serves as a crucial material within the construction sector, since it is the main material for various structures like residential and commercial buildings, roads, dams, and bridges. However, concrete's lifespan is limited, and thus continuous monitoring is needed to ensure structural safety.

On average, concrete structures’ life is equal to 50 years before it succumbs to factors like water, salts, and atmospheric gases, which induce acidification and corrosion of steel reinforcing rebars. The corrosion significantly reduces the load-bearing capacity of slabs, columns, and other structural components.

Preventive measures, e.g. applying protective layers to reduce carbon dioxide (CO₂) penetration, can extend concrete lifespan. However, timely intervention relies on the ability to accurately assess and characterize deterioration levels. Traditional methods involve labor-intensive and costly drilling for sample removal and subsequent laboratory analysis, which is complicated and potentially hazardous, particularly in less accessible locations.

The IF-USP's Nanomaterials and Applications Laboratory (LNA) devised a catalyst based on layered double hydroxide (LDH) — or anionic clay — incorporating trivalent europium (Eu3+) to produce orange-to-red luminescence. Under ultraviolet light exposure, the material's luminescence shifts in color according to carbonate absorption levels, offering a real-time indicator of concrete deterioration. Based on the above, the researchers aim to develop a sensor capable of detecting luminescent material and evaluate its performance under real-world conditions.

Beyond enhancing building safety, the novel technique holds promise in reducing costs and carbon emissions. Extending existing buildings' lifespans means that no investment in new constructions is needed, aligning with global efforts to decrease greenhouse gas emissions, 8% of which originate from the construction industry's concrete production and processes.