Monitoring and assessment of azulejo panels decay: The 20^th century façade azulejos from Manuel Rocha building

¹ LNEC - National Laboratory for Civil Engineering, Materials Department, Avenida do Brasil 101, 1700-066 Lisbon, Portugal
² LNEC - National Laboratory for Civil Engineering, Geotechnics Department, Avenida do Brasil 101, 1700-066 Lisbon, Portugal
³ LNEC - National Laboratory for Civil Engineering, Concrete Dams Department, Avenida do Brasil 101, 1700-066 Lisbon, Portugal
⁴ HERCULES Laboratory, Évora University, Palácio do Vimioso, 7000-654 Évora, Portugal
⁵ LNEC - National Laboratory for Civil Engineering, Buildings Department, Avenida do Brasil 101, 1700-066 Lisbon, Portugal

^* Corresponding author: spereira@lnec.pt

Abstract

This study investigates the deterioration of the 20th-century azulejo façades of the Manuel Rocha Building in Lisbon. A multi-technique approach, including SEM-EDS, XRD, GPR, thermography, and hyperspectral imaging, was used to characterise materials and assess decay. Photogrammetry and digital image processing enabled mapping of pathologies and reconstruction of the decay chronology. Results indicate rapid degradation, with some panels reaching a critical state of degradation if no intervention is undertaken. The presence of alkali-silica gels suggests that alkali-silica reactions may be a key factor in glaze detachment. Findings highlight the urgency of conservation measures and the value of integrated monitoring strategies for heritage preservation.