Self-sensing damage assessment and image-based surface crack quantification of carbon nanofibre reinforced concrete Savas ß Erdem a,⇑ , Serap Hanbay a , Marva Angela Blankson b a Department of Civil Engineering, University of Istanbul, Avcilar Campus, Istanbul, Turkey b School of Engineering, The University of Technology Jamaica, Kingston, Jamaica highlights  Monitoring damage and deformation on the concrete column.  Crack profiles by means of 3D image analysis and fractal theory.  Composites with carbon nanofibre, carbon fibre and steel fibre.  Carbon nanofibre maintains the compactness in a fractured concrete. article info Article history: Received 28 August 2016 Received in revised form 22 November 2016 Accepted 29 December 2016 Keywords: Self-sensing Concrete Compressive damage Carbon nanofibre Crack analysis abstract Concrete is used extensively in the construction of civil infrastructures such as bridges. The development of cracks can however, undermine the integrity of such facility. In this research, the self-sensing damage of cementitious composites with three different types of fibres (carbon nanofibre, carbon fibre and steel fibre) were experimentally investigated. In addition to, the crack profiles were digitized and analyzed by means of 3D image analysis and fractal theory. The results show that, with the exception of steel fibre, the fibre reduced the strength of concrete. The modulus of elasticity of concrete were all minimised with the use of the different types of fibres. Most importantly, it was shown that the carbon nano fibre was not very effective in minimising the development of micro cracks but was effective in maintaining the com- pactness of concrete; the carbon nanofibre and steel were effective in mitigating the development of high volume of micro cracks but the latter was not quite as effective in maintaining compactness. The carbon nanofibre on the other hand, not only reduces development of fracture but contributes to the mainte- nance of compactness in the fractured concrete. Ó 2016 Elsevier Ltd. All rights reserved. 1. Introduction The use of concrete on most construction project is inevitable as this material has a number of favourable properties. However, con- crete is a brittle material and is susceptible to development of cracks within the matrix. The manifestation of minute cracks sometimes serves as warning of stress concentration in specific areas, but the cracks may propagate and contribute to sudden col- lapse. This situation represents one of the biggest disadvantages of the concrete. Durability is an important aspect of concrete bridge design, especially for bridges that will be subjected to continuous dynamic loading and the involuntary establishment of cracks can compromise this characteristic of the concrete. Therefore, monitor- ing of concrete that will result in the avoidance or mitigation of harmful cracks during the construction and the service life stages should be pursued at all times. This process underscores the neces- sity of a structural health monitoring programme. Minnesota Transportation Department, in a report published in 2009 [1], defined the aim of the structural monitoring as bringing forth awareness to integrity of in-service structures continuously in real-time. Scheduled maintenances and periodic inspections provides only limited data about the structural health of concrete bridges and these methods are not cost-effective in terms of cost associate with labor and downtime of these structures. Neverthe- less, through innovations in detection technology, material and structural damage characterizations is made possible with special diagnostic technology that provides continuous monitoring and real-time control of the structure of interest [2]. From this point of view, the core mandates of structural health monitoring are detection of damage and control of structures which are done by minimum labor-force through the provision of autonomous http://dx.doi.org/10.1016/j.conbuildmat.2016.12.197 0950-0618/Ó 2016 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: savas.erdem@istanbul.edu.tr (S. Erdem). Construction and Building Materials 134 (2017) 520–529 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat