Analyzing the efficacy of SAF (sulfonated acetone formaldehyde) as mechano-luminous (ML) material for detecting incipient crack

Certainly, the presence of cracks plays a pivotal role in assessing the structural integrity of civil infrastructure. The existence of early age cracking in concrete presents a considerable risk to the long-term durability of structures. In the field of crack detection, numerous techniques are available, among which crack luminescence stands out as an innovative and easily accessible method for identifying incipient cracks. In this study, the luminescent properties of sulfonated acetone formaldehyde (SAF) were examined in conjunction with vinyl acetate ethylene (VAE) for the purpose of detecting cracks in a substrate. The progression of cracks was systematically monitored and recorded under 365 nm UV radiation. The severity of the cracks was analyzed in relation to different flexural stress and strain conditions. In this study, crack initiation was observed at a flexural strain of 1.2%, corresponding to a stress of 1.1 MPa. Subsequently, mild crack propagation was observed on both sides of the specimen at a strain value of 1.5%, with a corresponding stress of 2.2 MPa. The failure occurs within a strain region of 2.1% and corresponds to a stress value of 5 MPa. Once the flexural strain surpasses 1.2%, crack propagation initiates, gradually accelerates, and leads to failure with a reduced strain rate. The results highlight the utilization of SAF-VAE-based mechano-luminescence as a crack detection sensor. This approach offers potential benefits for identifying and analyzing the severity of cracks in construction structures, leading to improved safety, timely maintenance, and enhanced structural integrity. This technology offers a reliable and efficient method for detecting and monitoring cracks, ultimately contributing to the overall safety and longevity of the built environment.