鉄筋コンクリートの超長期複合劣化過程の反応型非定常拡散方程式による解析的考察

Abstract

In this study, combined deterioration mechanism in reinforced concrete with CO2, flying salt, acid rain is reconstituted by transient reaction-diffusion equation and super long-term deterioration process is analyzed in RCP scenario.This method is confirmed to be consistent with research of the past about carbonation and to be suitable for complex hysteresis in RCP scenario.Simple formula for building group is also formed and reliability design method with mixture distribution of carbonation in several RCP scenarios is proposed. Probability of carbonation by mixture distribution increases in durable member with thick cover depth after 100 years. RCP 100 1) 40 2),3) 4 DuCOM Lecca CIKS Life-365 Life365 SIMCO STADIUM DuCOM Lecca CIKS Life365 STADIUM * Graduate Student,

Agent‐based modeling of super‐long‐term maintenance processes for RC building groups: Stochastic study of risks of building groups by super‐long‐term combined deterioration Part 2

“…In this study, we visualize the process of the combined deterioration of reinforced concrete (hereinafter referred to as "RC") building groups in the super-long term stochastically by modeling the transient-reaction-diffusion equation of CO 2 , flying salt, acid rain, and ultraviolet radiation (hereinafter referred to as "UV"); by modeling reinforced concrete structures with multiple finishing materials and multiple repair methods; and by calculating the probabilities of the corrosion of reinforcements. In a previous paper, 5 after we constructed a basic deterioration model of RC members and confirmed it as an appropriate method for super-long-term estimation, we proposed a simplified formula and reliability design method for building groups. Although we model the deterioration of finishing in this paper, there is a critical problem: we have no deterministic method to estimate building owners' preferences over several generations for selecting the specifications of finishing materials and repair methods.…”

“…15 We assume the valuen a day with precipitation as half the value during a nonprecipitation day using the assumption for tilted-surface solar irradiance described in a previous paper. 5 In addition, although the sunlight in the room depends on the areas, the directions of openings, and the specifications of glass, and the lighting adds to the UV amount, we assume the intensity of UV indoors as half the value in the outdoors for the sake of simplicity.…”

“…The values are mere reference because they do not represent the compatibility of different types of paints. In addition, we obtain constants for indoor conditions by using the UV and acid rain in the outdoors and by obtaining the permeability of moisture as a function of the permeability of CO 2 regardless of indoor or outdoor conditions according to the literature research results by Pak et al 17 Figure 2 shows the carbonation depth of concrete with W/C: 0.65 5 Moreover, most of the polymeric-finish coating materials used in RC structures are composed of different layers at each location of the surface: top coatings, main coatings, and under-coatings. However, when the carbonation reaches deeper than the individual width of each part at the surface, the difference in location becomes unclear when evaluated by the two-dimensional transient-reaction-diffusion equation with a mesh of 1 mm.…”

“…This is caused by the dependence of the reaction item. 5 Then, Figure 3 shows that the effect of the continuous repainting is time-dependent. From these analyses, we recognize the necessity of a new deterioration model of concrete with polymericfinish coating materials for the super-long term.…”

“…However, the simplified formula for concrete with no coating described in the previous report is not suitable for histories of the carbonation of concrete with repairs in accordance with deviations from the outline of the history of the CO 2 concentration in the RCP scenario. 5 Therefore, we emphasize that only the outline of the carbonation history is needed in the formal analysis and the progress of carbonation between large-scale repairs is within 1 mm at the long-term, for example, after the repair at 50 years shown in the above figures. We establish rules in which carbonation does not progress for 5 to 15 years after recoating, and the difference from the carbonation history of concrete with nonrepaired top coatings disappears within 50 years.…”