To overcome the problem of non-compatibility of the non-intrinsic sensor with cementitious materials, the development of intrinsic piezo-resistive sensor made with cementitious composites in the past few decades has reshaped the field of Structural Health Monitoring (SHM). Non-intrinsic sensors are expensive for monitoring and susceptible to damage under different environmental conditions. However, heterogeneity in the material of sensor and cementitious material poses serious concern over the long-term application of these sensors. Traditional non-intrinsic based sensors such as strain gauges, optical fibers, shape memory alloys were used to monitor responses of the structure like stress, strain under external loading. Therefore, it is now considered judicious to monitor the condition of a structure continuously before it loses its serviceability. In Europe, it is estimated that about 50% of construction sector budget is utilized for the rehabilitation and maintenance of existing infrastructure. However, proper monitoring of the existing infrastructures and timely repairing of the damage part of structures help to minimize the requirement of cement production for the re-construction. It is roughly estimated that cement industry produces around 5% of global greenhouse gas emissions. One cannot avoid the construction of new infrastructures to meet the requirement of population.Īs the production of cement is increasing day-by-day, it is leaving negative impact on the environment. Therefore, there is a huge demand of constructing the new infrastructures for the need of ever growing population of the world as well as the re-construction of the existing structures. The demand of the cement is increasing because concrete materials start to deteriorate not only under mechanical stress but also under harsh environmental impacts such as the action of weathering, chemical attack, abrasion, corrosion, or other processes that compromise its durability. Nowadays, most of infrastructures are being constructed with cementitious materials including social infrastructures such as residential and commercial buildings, network of transport system such as highways, runway at airports and large structures such as dams and barrages. This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The maximum variation in fractional change in voltage (FCV) shown by plain mortar is 6.3% indicating high electrical resistance of plain mortar, while in case of mortar containing 1% A-CNTs, variation in FCV is 35% indicating lower electrical resistance and better sensitivity of the material. The test results of self sensing measurements indicate a poor repeatability of the electrical response for plain mortar under each loading cycle while, stable response is noticed with specimens incorporating 1% of A-CNTs. This indicates that content higher than 1% of A-CNTs is not required for the development of smart cementitious composites for structural health monitoring (SHM). With the use of 1% content of A-CNTs, a stable resistivity response of the material is observed irrespective of the saturation degree. However, the impact of P-CNT and A-CNT on the reduction of mechanical properties is slight. Results showed a detrimental effect of dispersive agent on the resistivity and mechanical properties of cementitious composites irrespective of the content of CNTs. Self-sensing response of the material under cyclic compressive loading is measured with Wheatstone Bridge (WSB) circuit. Two contents (0.5 and 1% by mass of cement) of MWCNTs are investigated and three different techniques were used to disperse CNTs in water by sonication: (i) pristine, P-CNT, (ii) functionalized carbon nanotubes by classical approach (dispersive agent, D-CNT), and (iii) by an innovative approach (annealing, A-CNT). The impact of dispersion is observed through electrical resistivity and mechanical properties of cementitious composites. * e-mail: study focuses on different techniques for dispersing Multi-Walled Carbon Nanotubes (MWCNTs) in cementitious materials. Shaban Shahzad *, Ahmed Toumi, Jean-Paul Balayssac, Anaclet Turatsinze and Vanessa Mazars
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