## 4 Conclusions  
This research proposed an approach to estimate the output of the degradation model based on the durability index according to the potential risk concerning input data (\(S_{f}\) and \(P_{f}\)). The degradation model is useful for assigning corrective actions for dangerous RC components during emergency conditions. It is also necessary the planning frequent inspections and preventive maintenance in terms of RCM for the quality control of infrastructures.  
After pre-posterior analysis and defining risky RC components, the degradation model was estimated based on the durability index. Based on the image processing results, the damage growth rate was 24% during the definite time in this load-bearing RC component. If this definite time spans 6 months, this case had three milestones during the testing. The first data gathering was carried out on the intact RC component, and the second milestone occurred simultaneously with the initial damage growth of 12%. Meanwhile, the final and third milestone with 24% damage was measured by this proposed method. If severity and probability considering for risk calculation, the component durability index will be extracted  
Figure 6: Degradation of reinforced concrete [43].  
based on variable reliability over the life of the component as a degradation model during operation. In other words, if service limit and ultimate limit are considered as thresholds in the degradation model, it is possible to estimate the next step of a structure's status based on the degradation model and compare the next step of the structure status with the expected structure status [25]. In this case, the \(D_{i}\) was estimated at 0.02 for the definite time of inspection as a temporary durability index to estimate the degradation model.  
Image processing was exploited as a tool to reach the research aim. Meanwhile, this research not only compares the operators of image processing but also combines the data gathering with mathematical tools and a statistical approach in terms of the risk concept. Merging the data processing in terms of vulnerable zones with image processing tools to find the maximum difference between the image processing operators in each element helps the user to decide on maintenance planning using the hybrid approach. Additionally, this comparison approach maximizes the value of information after data gathering by the image processing operator.  
Finding the damage growth and estimating the degradation trend is not possible through traditional visual inspection. More than simply proposing structural health monitoring tools for data gathering, this quantitative method estimates the status of reinforced concrete without in-person observation. Therefore, regardless of human error elimination, the computer records data and trends those data with a risk logic concept to prioritize vulnerable zones based on their degradation rate.  
Study conception and design; data collection; analysis and interpretation of results; draft manuscript preparation: S.M.S.L. Supervising the research project: F.M.N. Research consultant: M.R. All authors have read and agreed to the published version of the manuscript.  
The authors received no financial support for the research, and publication of this article.  
All data that support the findings of this study are available from the corresponding author upon reasonable request. Additionally, all data used during the study appear in the submitted article.  
I would like to express my very great appreciation to [PERSON] for his valuable suggestions during the development of this research work. His willingness to give his time so generously has been very much appreciated. Finally, I wish to thank my parents and my wife for their support and encouragement throughout my study.  
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.