A life-time reproducible mechano-luminescent paint for the visualization of crack propagation mechanisms in concrete structures

Mechano-luminescent (ML) paint consisting of SrAl₂O₄:Eu²⁺,Dy³⁺ powders and transparent epoxy resin could reveal the complex crack initiation and propagation evolved from the Brazilian test of conventional concrete. ML paint also showed excellent fatigue resistance in terms of mechanical strength and optical ML durability, even in weatherproof. Although the intensity of emitted photons from ML paint has been reduced as the number of repetitive stress cycles increased, however, the deterioration of ML intensity with the variation of additive stress cycle was less than 5% in the cases of high cycle failure. Consequently, the life time reproducibility of ML paint allows the possibility to characterize the long-term integrity of various concrete structures.