Nano Electro Mechanical Systems (NEMS) can be used for better quality control of concrete, which indirectly helps to improve its durability. NEMS are wireless nanomachines designed to measure (i) density and viscosity of green concrete during mixing and pumping, (ii) strength development, (iii) shrinkage stress, (iv) parameters affecting concrete durability such as temperature, moisture, chloride, pH and carbon dioxide [MaCoy et al. 2005].
Microelectromechanical systems (MEMS) has been used to measure temperature and internal relative humidity (RH) of concrete by utilizing microcantilever beams and moisture-sensitive thin polymer. MEMS were found to be (i) effective and sensitive in measuring concrete temperature and moisture and (ii) durable under corrosive environment and internal / external stresses. Monitoring temperature and moisture is very important in order to (i) monitor setting and hardening characteristics of concrete and (ii) predict the possibility of occurrence of concrete chemical distresses such as corrosion of steel reinforcement, freeze-thaw distress, carbonation and alkali-aggregate reaction. The areas that need further investigation are (i) long-term behavior and repeatability of MEMS embedded into concrete, (ii) wireless interrogation such as signal processing, powering, communication, location, orientation, data storage and computation capabilities.
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