The nonhomogeneity of concrete leads to randomness in the development and extension of cracks. Scholars have proposed different models to analyze the development of cracks. Different from existing works on crack development, in this paper, we establish a crack spacing model on the basis of the mechanical equilibrium relation of differential elements. We also establish a mechanical equilibrium model considering that the shrinkage of concrete is constrained by the bonding force of reinforced concrete. Then, on the basis of the equilibrium condition, we propose an analytical model of spacing between the first crack and the second crack at the interface of steel and concrete due to corrosion expansion. This calculation model has only three variables: tensile strength, effective constraint length of the reinforcement, and bond force. In addition, the parameters are clearly defined. We verified the development of cracks at the interface between steel bar and concrete under chloride corrosion at different locations in a steel bar by comparing it with existing simulations and experimental results. The analytical model proposed in this paper has an accuracy of 92%, indicating that our expression for crack spacing can effectively predict the location of cracks.

The objective of this study was to understand the drinking water quality state in the Inner Mongolia Autonomous Region from 2014 to 2018 and to derive information that will provide a basis for improving the drinking water quality in the region. Monitoring data for drinking water from the Inner Mongolia Autonomous Region for 2014 to 2018 were analyzed and the results were compared with GB 5749-2006, the Standard Test Method for Drinking Water, and GB 5749-2006, the Drinking Water Quality Standards. Data for a total of 30,613 water samples were assessed. Of the data for the microbiological index, sensory trait and general chemical index, and toxicological index, 89, 80, and 69% were qualified, respectively. For the toxicological index, the fluoride and nitrate nitrogen data were the least compliant. The water quality in all the cities was generally very suitable for drinking. However, there were marked differences in the qualified rates of drinking water in different areas and the qualified rates of the data for the three indexes were lower in rural areas than in urban areas. Given the varied issues with the drinking water quality, the relevant departments of League cities should implement appropriate and effective treatment measures to improve the drinking water quality and ensure it is safe for residents.