Sufen Dong

Smart concretes and structures: A review

Smart concretes and structures are intelligent systems that have properties different from normal concrete, such as self-sensing and self-healing properties, or have the ability to react upon an external stimulus, such as stress and temperature. The “smartness” of concrete and structures is achieved through material composition design, special processing, introduction of other functional components, or modification of the microstructure. They are designed to meet specific requirements through tailored properties for improving serviceability, safety, reliability, longevity, and durability of the infrastructures and reducing the life-cycle costs of the infrastructures. This article reviews the recent researches of various smart concretes and structures, with attentions to their principles, fabrication, and properties. Future challenges in the development and applications of smart concretes and structures are also discussed.

Design and Implementation of a Multiple Traffic Parameter Detection Sensor Developed With Quantum Tunneling Composites

Quantum tunneling composites (QTCs) are extremely sensitive to external force due to the quantum tunnel effect and have been developed into various sensors used in many fields, such as force sensors and tactile sensors. In this paper, a new type of traffic detection sensor is developed based on QTCs which are fabricated by adding spiky spherical nickel powders as functional fillers into silicone rubber. The developed sensors with different sensitivities were incorporated in an experimental road and a real road, and their performances for traffic detection were investigated. Test results show that the QTC sensors with high sensitivity can accurately detect the passing of different vehicles under different vehicular speeds and test environments. The double-rows QTC sensors can measure vehicle speeds easily and precisely. It is possible to measure the vehicle speeds with one QTC sensor per lane. A lot of other traffic data, including vehicle presence, vehicle weigh-in-motion, position, vehicle occupancy rate, vehicle count, and vehicle classification in real-time traffic can be achieved by the QTC sensors with the advantages of high detection precision, fast response and recovery excellent robustness, energy saving, easy installation, and maintenance. The obtained results prove the applicability of the QTC sensors for long-term real-time traffic parameter detection.

Nano carbon material–filled cementitious composites: Fabrication, properties, and application

Abstract Advances in nanotechnology have opened up a wide range of opportunities for engineering properties of cementitious materials using nanoscale reinforcements. Development of this new class of cementitious composites has resulted in extensive academic and industrial research regarding the processing, characterization, and modeling of these materials. Nano materials, especially nano carbon materials (NCMs) including carbon nanofibers, carbon nanotubes, and nano graphite platelets, were found to be able to improve the mechanical property, durability, and functional properties of cementitious materials due to their excellent intrinsic properties and composition effects. This chapter introduces advances in NCM-filled cementitious composites with an aim at high-performance and multifunctional properties for structural applications. Key issues in research of NCM-filled cementitious composites (e.g., fabrication, properties, and mechanism) are addressed, along with challenges to add the reinforcing effect of NCMs to conventional cementitious composites and infrastructures made of them.

Quantum Tunneling Composites and Detectors for Intelligent Transportation Systems

The quantum tunneling composites can be used to develop new sensors, switches and controls for a wide range of applications including electronics, transport, space, medicine, defense, textiles, oil and gas, and civil engineering. In this paper, the pressure-sensitive behavior and mechanism of quantum tunneling composites were investigated. The quantum tunneling composites were used to develop traffic detectors for intelligent transportation systems. Research results indicated that quantum tunneling composites have ultrahigh sensitive response of electrical resistance to external loading, which results from field emission effect induced tunneling conduction. The developed detectors based on quantum tunneling composites exhibit such advantages as high sensitivity, fast response time, low cost and easy installation. They have great potential for monitoring traffic parameter, thus providing data support for intelligent transportation systems.