Abstract: 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.

Abstract: 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.

Abstract: An estimation device has: determination unit for acquiring a characteristic color of reinforced concrete in a dry state from an initial image obtained by capturing an image of a concrete surface of the concrete, analyzing a first image of the concrete surface that is captured after spraying water onto the reinforced concrete, and determining a portion having a predetermined color difference from the characteristic color as a crack; and an estimation unit for impregnating the crack with water, analyzing a second image of the concrete surface that is captured after the concrete surface is dried, and estimating whether or not the inside of the crack is carbonated, using a color around the crack.

Abstract: 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.

Abstract: Provided is a method for evaluating a hydrogen embrittlement fracture risk of an iron reinforcing bar that is performed by a hydrogen embrittlement fracture risk evaluation apparatus, the method including: a fracture probability curved surface generation step of obtaining a fracture probability curved surface representing a probability of the iron reinforcing bar fracturing by performing regression analysis on results obtained by repeatedly carrying out a hydrogen embrittlement test while changing an amount of hydrogen absorbed in the iron reinforcing bar provided in a concrete structure and a tensile stress applied to the iron reinforcing bar and using the amount of hydrogen and the tensile stress as variables; a lower limit stress acquisition step of acquiring, from the fracture probability curved surface, a lower limit stress property representing a relationship between a lower limit stress that is a lower limit of the tensile stress at which no fracture occurs in the iron reinforcing bar at a predetermine

Abstract: 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.

Abstract: A cumulative distribution function of fracture time is calculated from large quantities of hydrogen embrittlement fracture test data measured under test conditions that assume reinforcing bars in prestressed concrete, transition probability is calculated from the cumulative distribution function of fracture time with a hydrogen embrittlement fracture being regarded as a stochastic process through which a degraded state progressively reaches a fractured state, and the time integral of the transition probability is found as the degree of progress of hydrogen embrittlement.

Abstract: 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.