Assessment of Concrete Surfaces Using Multi-Spectral Image Analysis

L. GONÇALVES

Adjunct Professor

INESC, Pol. Inst. of Leiria Leiria, Portugal luisa.goncalves@ipleiria.pt

L. Gonçalves, is adjunct professor at the Polytechnic Institute of Leiria (IPL). Received her PhD in Civil Engineering from the Univ. of Coimbra in 2009. She is the coordinator of the Civil Engineering course at the School of Technology and Management of IPL.

E. JÚLIO

Full Professor

ICIST, DECivil IST-UTL,

Lisbon, Portugal

ejulio@civil.ist.utl.pt

E. Júlio is a full professor at the Instituto Superior Técnico of the Technical University of Lisbon. His research interests are in the field of Structural Concrete. He is member of IABSE WC 3, fib Commission 5 and ACI 364 Committee.

In this paper, the authors present a method, SURFCRETE – Multi-spectral image analysis of concrete surfaces, designed to detect, analyse and measure areas with biological colonization, stains and/or repaired materials in exposed concrete surfaces. The technique was performed using four multi-spectral bands (blue, green, red and near infrared). A vegetation index was also computed, which was used as additional band information. The method was tested to classify surface images of concrete buildings where biologic colonization, exposed aggregates and/or repairing mortars were detected. Results show that, with SURFCRETE, more accurate outputs may be driven using the near infrared band. Furthermore, SURFCRETE proved to be precise and efficient. In addition, surface mapping and statistical results are automatically obtained and stored in digital format, requiring much less processing time.