© 2018 JETIR July 2018, Volume 5, Issue 7 www.jetir.org (ISSN-2349-5162)
JETIR1807800 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 523
Structural Health Monitoring Using Carbon Fibre
Reinforced Concrete
Mir Suhail
1
, C.Arvind Kumar
2
and Masoom Reza
3
1
M.tech, 4
th
Semester, Department of Civil Engineering, Al-Falah University, Faridabad, 121004, India.
2
PhD Scholar, Department of Civil Engineering, NIT Srinagar, 190006, India.
3
Assistant Professor, Department of Civil Engineering, Al-Falah University, Faridabad, 121004, India.
Abstract: Self-sensing concrete (SSC) refers to a structural material that can monitor itself without the need of any embedded, attached or
remote sensors. By measuring electrical resistance of the self-sensing concrete, the stress, strain, crack and damage can be in situ monitored.
Compared with conventional structural materials which require additional sensors for monitoring or detection, the SSC is advantageous in
terms of high sensitivity, good mechanical property, natural compatibility, identical lifespan with concrete and easy installation and
maintenance. It has been found that carbon fibre reinforced concrete can function as a smart structure material that allows non-destructive
electrical probing for the monitoring of flaws. In this study the effect of addition of short carbon fibers (0.5-2.5% by weight of cement) on the
electrical behavior of concrete was investigated. Both strain and damage sensing properties of carbon fiber reinforced concrete were
investigated in the present study. Strain sensing tests were first made on the material’s elastic range, by gradually loading specimen up to
54KN. At the same time both strain and resistivity were measured. The former was controlled using strain gages, and the latter using a Key
sight digit multimeter on a two probe setup. The electrical resistance of carbon fiber reinforced concrete was found to decrease reversibly
upon increasing compressive loading and reversibly increased upon unloading.
Keywords: self-sensing concrete (scc), carbon fibres, strain gauges, resistivity.
Introduction
Concrete is the second most used resource in the world after water. Regardless of long service life of civil engineering infrastructures, they
cannot be considered as maintenance-free. These engineering structures are the most expensive investments and assets of any nation. Worldwide
incidents of tragic failures of civil infrastructures remind that suitable measures are required to avoid sudden collapse of civil structures and
associated loss of money and lives.
The weakening and failure of concrete structures occur mainly due to ageing of materials, aggressive environmental conditions, prolonged usage,
overloading, difficulties involved in proper inspection methods, and lack of maintenance. Within the microstructure of concrete, it contains
numerous cracks in nano-scale. These cracks are formed during manufacturing or use. With time, nano-cracks join to form micro-cracks, which
in turn, leads to formation of macro-cracks and failure of structures. Increasing concern about the status of existing structures, particularly after
earthquakes, has motivated numerous studies on damage detection using various non-destructive evaluation methods. Through early detection of
these inherent damages, sudden collapse and accidents can be avoided. Timely detection of damages and proper maintenance can greatly enhance
the service life of concrete structures.
Review of Literature
The structure of self-sensing concrete depends to a high degree on the composition of the composites. As a composite, self-sensing concrete
consists mostly of matrix materials (i.e., conventional concrete materials) and functional filler. In addition some auxiliary materials may be
necessary to disperse functional fillers into the matrix materials. Therefore, selection of suitable materials and determination of their proportions
are important for fabricating self-sensing concrete. The influence of the carbon fiber as a smart material was developed and application of carbon
fiber as a smart material for damage assessment and for static and dynamic loading. The carbon fiber reinforced cement as a strain sensing
coating was then after investigated.
Objective
Self-sensing carbon fibre based concrete has high sensing ability that can be easily applied for health monitoring purpose. But the addition of
these fibres changes the basic properties of concrete and hence the earlier method for conventional concrete cannot be applied directly to this
concrete. The primary objective of this research is to study health monitoring of concrete by casting sufficient specimens like cubes, cylinders
and beams reinforced with carbon fibres and without fibres and to form the co-relation between the conventional concrete and specimens
reinforced with carbon fibres. The main objectives of the work are:
To study the electrical resistivity behavior of concrete by adding various percentages of carbon fibers (0-2.5% by weight of cement).
To study the strain sensing and damage sensing ability of the fibre reinforced concrete.
To find the threshold percentage of carbon fibres for making effective self-sensing concrete.