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Traditional concrete can be provided with piezoresistivity by modification with carbon nanotubes. Such self- sensing composites can be used for fabrication of durable smart sensors for structural health monitoring. To allow the wide practical application of this technology various aspects having effect on the electrical properties of cement-based sensors must be studied. This research focuses on the effect of temperature and water content on electrical resistance of cement composite containing different amount of carbon nanotubes. Change of electrical resistance over curing time is also considered. Electrical resistance of composites is shown to considerably decrease with rise of temperature and increase with removal of water. It is recommended to measure the variation of electrical resistance of carbon nanotube cement based sensors with change of temperature and water content prior to their use to provide the adequate correction. [ABSTRACT FROM AUTHOR]

This paper presents the assessment of the strength at early age and automatic curing of concrete using the IoT (Internet of things). IoT can be used for SHM (structural health monitoring) and for other civil engineering applications. Evaluating the strength of concrete structures at early age is very important for a structural engineer, similarly the controlling the waste of water during continuous curing of concrete done manually is also a matter of concern. So the concept of assessing the early age strength using smart rock sensor and automatic curing using moisture sensors are installed to address the above issues in construction. The functioning of these entire processes can be monitored and controlled from remote location. [ABSTRACT FROM AUTHOR]

Civil structure is typically large-scale and it is complex in behavior and they create huge impact in modernized nations. Assessment of a structure's integrity is a challenging task. Studying and implementing structural health monitoring technique is becoming essential to predict the deformation in the structural components which may cause tremendous loss to human life as well as to economy. The prime objective of our proposal is to use sensors to incessantly keep an eye on the buildings and to build a warning system for the consumers prior to damage through Global System for Mobile communication (GSM). Prototype resembling the structural components like beam, column, etc. can be monitored by using various sensors like load cell, accelerometer and vibration sensor. The monocratic function of the Structural Health Monitoring (SHM) system involves detection of changes in the structures by sensors and it transmits the signal to the controller which ensures the threshold of the incoming signal. Real-time variation in magnitudes of loads, inclination and vibration are sent as SMS to users through GSM. Further physical phenomenon of structures can be monitored by using various sensors which guarantees the existing structure a smart one. [ABSTRACT FROM AUTHOR]

Some of the authors have recently developed a new nanocomposite cement-based sensor, termed "carbon nanotube cement-based sensor", for applications in vibration-based structural health monitoring of civil structures. The sensor is made of a self-sensing cement paste doped with multi walled carbon nanotubes. The mechanical deformation of this composite material results into a measurable change of its electrical resistance. Previous work was devoted to fabrication, dynamic characterization and to implementation in full-scale structural components. This work addresses electrical modelling of the sensor, and specifically seeks to validate a lumped circuit model for use in dynamic sensing. After a brief overview of carbon nanotube cement-based sensors, the electrical model is presented. Salient parameters of the circuit are identified on sensors with varying electrodes' morphologies. The results indicate that the proposed equivalent circuit model is capable of closely replicating the step response of the sensor to an imposed potential difference. Notably, such linear model is likely to anticipate superharmonic components in the electrical current in the response to sinusoidal mechanical deformations. [ABSTRACT FROM AUTHOR]