Water plays decisive role in the performance of concrete structures from construction to durability, including the timing of finishing the concrete substrate, indoor humidity, carbonation, chloride attack, frost damage, alkali-aggregate reactions and corrosion of reinforcement. Recent trends in the life cycle management of infrastructures need methods to This paper reviews studies and applications of methods for water content of concrete structures in terms of their measuring principles, applications and future prospects. Methods of measuring electric resistance and capacitance using embedded or contact electrodes are first dealt with and the results are evaluated with reference to the authors experiments. and sheet covering method. Particularly, the impermeable sheet covering and coloring paper methods are easy, non destructive and applicable to on-site decision of the timing for the finishing construction, while no information is given on the water content inside of the concrete. Finally, neutron method and direct core sampling method with low abrasion Water plays decisive role in the performance of concrete structures from construction to durability, including the measure water content of concrete in reliable, accurate and ease-of-use manners. Next, relationship between relative humidity measurement and water content is discussed both on the bore hole method heat are briefly discussed.

Sub-terahertz waves, electromagnetic waves with a frequency band of approximately 10 to 300 GHz, can penetrate non-polar materials like concrete while being absorbed by polar substances such as water. These waves exhibit high reflectivity against metals, including rebar, yet the corrosion products on the metal surfaces provide absorption or scattering. This study explores a non-destructive, non-contact methodology for assessing the corrosion level of rebar in concrete. Findings indicate that suitable frequencies exist for each cover concrete depth capable of evaluating rebar condition irrespective of moisture or chloride ion presence. Selecting the suitable frequencies enables the visualization of rebars up to a cover depth of approximately 50 mm. Furthermore, the study demonstrates that the magnitude of differential reflection intensity, adjusted for cover concrete depth, can indicate assessing rebar corrosion degree.

This paper concerns the λ type enforcement braking device (EBD) installed at road construction sites with the traffic-lane regulation for the traffic accidents prevention. The employment of the EBD may considerably increase the safety protection of drivers, pedestrians and workers in any road construction sites. In order to improve the EBD’s reliability, and in a consequence, to enhance the collision safety, the present authors recommend a thorough analysis of the device’s braking characteristics and the subsequent optimization of its structure. In our earlier papers, we already elaborated the optimized structure of the EBD for the shortening of the braking distance. However, these considerations which is effective for automobile collisions from oblique directions. Thus, we propose a device with seven arms placed in a fan-shape, where normally three parallel arms are arranged on the current type EBD. A simple model collision tests aenxdp ethrimeeorentits cawel crealcu clatioarriedns obuat sewd ithon thfoeu cro dniseffervreatint ona penperorgaych a n(dc omlloisiomenn) tuamn gplesrin caipnled wethreree edmifpfeloreyendt ivne oloucr itstiesud yo. f Thaneautomobile to the current and fan type EBD. Our results demonstrate the new kind of EBD (the one with fan-shaped arrangement of the arms) is effective for braking and halting automobile approaching from oblique direction towards the EBD.

Oil droplets of S/O/W emulsion were manipulated by magnetic field. This S/O/W emulsion is safflower oil, containing magnetic particles, dispersed in water. This S/O/W emulsion is prepared using SPG membrane. First, magnetic field were applied to the statically placed S/O/W emulsion by an electromagnet from the side. As a result, the oil droplets moved in the direction of the magnet. Then, the magnetic field were applied to the oil droplets of the S/O/W emulsion flowing in a bifurcated channel branching in two directions. As a result, more than half of the oil droplets were guided to one of the branches. These experiments showed the larger the diameter of the oil droplets and the stronger the magnetic field, the faster the oil droplets moved. The larger the diameter of the oil droplet, the more it was guided to one of the branches.