טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentYosef Lidor
SubjectMonitoring the Structural-Electrical Response of
Intelligent Carbon based Textile Reinforced
Concrete Beam
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Yiska Goldfeld


Abstract

Carbon based textile reinforced concrete (TRC) structures are potential candidates for the applications of smart and sustainable structural elements. The configuration combines thin walled concrete structures with integrated sensing capabilities. The textile reinforcement is made of high strength AR-glass rovings, which are organized in a bi-axial mesh configuration, and carbon rovings that are inserted within the main textile platform as part of the production process. The monitoring capabilities are achieved by taking into advantage the electrical conductivity of the continuous carbon rovings and by correlating its electrical resistance change to the structural health. In such a configuration, the carbon rovings simultaneously serve as the reinforcement system and as the sensory agent. The obtained hybrid system combines the two, usually separated, systems, i.e. sensory and reinforcement in a one single element. The study compares between coated and un-coated textiles capabilities to monitor the structural health and distinguish between different and accumulated levels of cracking. The study demonstrates that the micro and macro structural mechanisms of the TRC beams are reflected in the electrical signal and can be quantitatively correlated to the level of damage. It was shown that the sensing capabilities of the textile yields stable, repeatable, sensitive and consistent electrical readings for monitoring needs. However, in case of coated textile, while coating improves the structural performance, it limits the sensing capabilities in distinguishing macro-cracking scenarios. Furthermore, the study characterizes the piezoresistive capabilities of self-sensory carbon roving reinforcements by means of integrative gauge factors (GFs). Two approaches to correlate the structural response to the electrical response are suggested. The first is differential which deals with each of the structural states separately while the second is engineering approach that yields continuous correlation. In order to assess the structural health from the electrical response, the study propose a structural health monitoring procedure. It was shown that the structural response of the TRC beam can be estimated by the engineering GF and the electrical resistance change of the carbon rovings.