Nippon Telegraph and Telephone Corporation

Takuya Kamisho

Yosuke Takeuchi

Masayuki Tsuda

Ryuta Ishii

Masamitsu Watanabe

Takashi Miwa

Soichi Oka

Norihiro Fujimoto

Shota Oki

Masahiro Sotoma

An occluded hydrogen content estimation method implemented by an occluded hydrogen content estimation device performs an occluded hydrogen content estimation step in which, based on an occluded hydrogen unit content which is a content of hydrogen occluded in a metal due to a change in humidity from a wet state to a dry state, a period after the metal is placed, and meteorological data corresponding to the period for an area where the metal is located, a content of occluded hydrogen that is absorbed in the metal for the period after the metal is placed is estimated. In the occluded hydrogen content estimation step, the occluded hydrogen content is estimated by multiplying the number of rainfalls in the meteorological data by the occluded hydrogen unit content.

Storage hydrogen amount estimation method and device

To repair reinforced concrete easily and at low cost. An anticorrosion method includes infiltrating an anticorrosion solution held inside concrete of reinforced concrete into a vicinity of a reinforcing bar through the concrete to passivate the reinforcing bar, detecting that the anticorrosion solution is infiltrated to a surface of the concrete, and discharging, after detecting the anticorrosion solution, the anticorrosion solution to outside of the concrete to form an anticorrosive coating on a surface of the reinforcing bar.

Corrosion prevention method and corrosion prevention device

To improve the accuracy of estimating when a fracture occurred in the metal material. In the estimation apparatus, the fracture temperature estimation unit performs estimate calculation of the fracture temperature of a fractured metal material from the hydrogen embrittlement rate of the fractured metal material, the fracture occurrence time narrowing unit performs calculation by using the temperature information of the installation environment in which the fractured metal material is installed and narrow down the period during which the fracture temperature is obtained as the fracture occurrence period of the metal material, and the fracture time estimation unit performs estimate calculation of the timing of when stress was applied to the fractured metal material during the fracture occurrence period as the timing of when a fracture occurred in the metal material.

Estimation method

A repair apparatus for repairing damaged reinforcing bars in a structure includes a strip-shaped conductor including conductive wires arranged in a height direction, the conductive wires being arranged in parallel, a high-frequency current generation unit configured to supply a high-frequency current between the conductive wires of a first end side of the conductor and the conductive wires of a second end side of the conductor, and a connection body configured to connect the conductive wires to each other and connect the first end side and the second end side of the conductor so that the conductive wires form a coil, and the high-frequency current generation unit supplies a high-frequency current between a conductive wire at an upper end or a lower end of the first end side of the conductor and a conductive wire at a lower end or an upper end of the second end side of the conductor.

Repair device

Reinforced concrete is protected from corrosion without conducting an operation involving exposure of rebar. A reinforced concrete structure is provided with a storage part that is formed inside concrete of the reinforced concrete structure, and that retains an anticorrosion solution. The anticorrosion solution diffuses and permeates through the concrete from the storage part, prevents the concrete in the vicinity of rebar from drying, and passivates the rebar.

Reinforced concrete structure

To estimate a fracture starting point of steel due to hydrogen embrittlement with high accuracy. A steel fracture starting point estimation device includes a hydrogen concentration distribution calculation unit adapted to calculate a hydrogen concentration distribution in steel-to-be-estimated when the steel fractures due to hydrogen embrittlement; a local critical hydrogen content calculation unit adapted to calculate critical hydrogen content at which the steel-to-be-estimated fractures due to hydrogen embrittlement; and a fracture starting point estimation unit adapted to read the hydrogen concentration distribution out of a storage unit. To estimate, calculate, from the hydrogen concentration distribution, a location in the steel in which hydrogen concentration of the critical hydrogen content is distributed, and designate the location in the steel as the fracture starting point of the steel-to-be-estimated.

Method for estimating steel rupture starting point, device for estimating steel rupture starting point, and program for estimating steel rupture starting point

To easily detect a crack having occurred in a steel material. A current measurement device measures a value of a current flowing through a target steel material that is immersed in an electrolyte aqueous solution and applied with tensile stress while subjected to hydrogen charging, and a device for detecting the occurrence of a crack or the like uses the measured current value to determine the occurrence of a crack in the target steel material when the amount of change in the current flowing through the target steel material, the change rate of the amount of change in the current, or the change rate of the change rate of the amount of change in the current exceeds a threshold value. The device for detecting the occurrence of a crack or the like determines the occurrence of a crack in the steel material when the change rate of the change rate of the amount of change in the current is less than a negative value of an absolute value of the threshold value, and determines the occurrence of fracture in the steel material when the change rate exceeds the absolute value of the threshold value.

Method for detecting occurrence of cracks and the like, device for detecting occurrence of cracks and the like, and program for detecting occurrence of cracks and the like

An accelerated corrosion test apparatus includes: a moisture sensor disposed near the reinforcing steel exposed from a cracked portion of concrete; a weight measuring instrument that measures a weight of the reinforced concrete specimen; and a control terminal that is connected both to the moisture sensor and to the weight measuring instrument and controls a temperature and humidity control device, thereby alternately and repeatedly performing a wetting step of supplying moisture to the inside of a crack in the cracked concrete, and a drying step of removing moisture in the inside of the crack and moisture on the exposed surface of the reinforcing steel, wherein the control terminal terminates the wetting step and starts the drying step when moisture is detected in the moisture sensor, or when change in slope of weight change of the reinforced concrete specimen is detected, after the start of the wetting step.

Method and apparatus for accelerated corrosion testing

A composition ratio calculating unit configured to calculate a first composition ratio that is a ratio of substance quantities of rust collected from a broken surface of internal steel of an updated old concrete structure and a second composition ratio that is a ratio of substance quantities of rust collected from a surface different from the broken surface, a composition ratio calculating unit configured to calculate a first corrosion time corresponding to the first composition ratio and a second corrosion time corresponding to the second composition ratio from characteristics representing a relation between a first corrosion time and the first composition ratio and a relation between a second corrosion time and the second composition ratio, respectively, and a breaking time calculating unit configured to calculate a time for the internal steel to break by subtracting the first corrosion time from the second corrosion time are included.

Fracture time estimation device for internal steel and method

To estimate penetration behavior of hydrogen up until hydrogen content reaches saturation even if load stress on steel is equal to or higher than threshold stress. A hydrogen penetration behavior estimation device includes a first measurement data input unit adapted to input first measurement data concerning variation of hydrogen content with time up until hydrogen content in steel-to-be-estimated reaches saturation when measurements are taken by applying such stress to the steel that no hydrogen embrittlement fracture occurs; a second measurement data input unit adapted to input second measurement data concerning variation of hydrogen content in the steel-to-be-estimated with time up until the steel fractures when measurements are taken by applying such stress to the steel that hydrogen embrittlement fracture occurs; a ratio calculation unit adapted to calculate increases in hydrogen contents in an initial stage of measurement and calculate a ratio of the second measurement data to the first measurement data in terms of increase in hydrogen content; and a saturated hydrogen content calculation unit adapted to multiply saturated hydrogen content based on the first measurement data by the ratio and designate the product as saturated hydrogen content of the steel-to-be-estimated, the saturated hydrogen content being reached upon application of such stress that hydrogen embrittlement fracture occurs.

Method for estimating hydrogen absorption behavior, device for estimating hydrogen absorption behavior, and program for estimating hydrogen absorption behavior

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Musashino, Japan

Takuya Kamisho