Civil infrastructure is essential to modern transportation but is continuously exposed to environmental stressors such as water, climate change, and heavy traffic, leading to degradation. Structural Health Monitoring (SHM) systems have been developed to support maintenance and safety; however, their widespread adoption is limited by high costs, durability issues, transmission instability, and complex data management requiring specialized expertise.

Self-reporting structures offer a promising alternative by enabling intuitive damage detection through visible signals. Inspired by biological systems, color changes can serve as direct indicators of anomalies. In this context, mechanochromic materials—capable of changing color in response to external stimuli—represent a transformative approach for SHM. Although widely studied in other fields, their application in civil engineering remains limited, and mechanochromic materials have not yet been engineered for large-scale infrastructure monitoring.

CHROMA will pursue the following ambitious objectives: (1) explore diverse color patterns, inspired by the principle that “all that glitters is not gold”; (2) develop, for the first time, a comprehensive SHM approach for concrete infrastructures based on a self-reporting mechanochromic spray coating, mimicking a biological skin responsive to external stimuli; (3) achieve accurate material characterization, focusing on performance, stimuli-responsiveness, environmental dependency, pH sensitivity, environmental impact, and compatibility, with particular attention to liquid crystal-based and colloidal systems; (4) conduct an extensive experimental campaign at reduced and full scale using a custom environmental-controlled setup to assess self-reporting capabilities; and (5) develop standardized deep learning computer vision tools (e.g., CNNs, ViTs) to automatically detect and interpret color-based damage patterns.

CHROMA will develop a new generation of self-reporting structures through cost-effective mechanochromic coatings, providing
instant visual feedback on mechanical stress, strain, or damage. Key outcomes include: large-scale deployment of SHM solutions for critical infrastructures;
continuous structural assessment via deep learning computer vision techniques (CNN and ViT); real-time diagnostics with color changes indicating structural
issues,e.g., cracks or pH shifts (pattern recognition); augmented reality-based support in human inspections, enabling guided visual inspections.

CHROMA is a high-risk/high-gain project introducing mechanochromic materials as a disruptive paradigm for Structural Health Monitoring (SHM), replacing conventional sensor-based systems with bioinspired, self-reporting materials. It will pioneer large-scale applications of mechanochromic coatings, enabling real-time, visual damage detection supported by AI-based interpretation tools. The project will deliver a power-free, scalable, and cost-effective monitoring strategy, reducing maintenance costs and extending infrastructure lifespan. CHROMA will enhance safety, support policy decisions, and promote sustainable and resilient infrastructure, with potential applications beyond civil engineering.