摘要: |
The most economical approach to maintain existing concrete bridges is by adopting an active preventive maintenance approach. An in-depth investigation of the combined deterioration effects of various deterioration mechanisms is needed to establish sound thresholds for harmful chemicals in concrete bridge elements. Such established thresholds are critical for cost-effective maintenance of concrete bridges. This study investigated the economy of preventive maintenance for concrete bridges. This report presents an in-depth chemical evaluation and preventive maintenance of existing highway concrete bridges. In addition, it presents implementation of the proposed preventive maintenance approach that is based on quantitative assessment of the material chemical condition of the bridge. This research project involved the following activities: (1) Review of the current bridge inspection manuals for concrete bridges evaluation, (2) Identification of various deterioration mechanisms, (3) Extensive presentation of chemical NDTs, (4) Establishment of chloride diffusion coefficient, (4) Required preventive maintenance measures for different levels of harmful compounds found in concrete bridges, (5) cost of various activities presented in items 1-4, (6) Comparison of concrete bridge maintenance costs using the current practice and the proposed preventive maintenance approach. Based on the finding of this study, preventive maintenance may require slightly higher initial cost, however, it leads to long-term cost saving over the service life of bridges. |