This report is a manual that provides step-by-step procedures for assessing the condition of corrosion-damaged bridge elements. It also includes procedures that can be used to estimate the expected remaining life of reinforced concrete bridge superstructure elements and to determine the effects of maintenance and repair options on their service life. This http://gulliver.trb.org/publications/nchrp/nchrp_rpt_568.pdfmanual should be of interest to state engineers and others involved in the design, construction, and maintenance of highway bridges. Corrosion-induced deterioration of reinforced concrete bridge superstructure elements is a common and costly problem in the United States. A rational decision regarding maintenance, repair, or replacement of such deteriorated elements must take into account the condition of the element, the extent of deterioration, the expected remaining service life, and the impact of alternative maintenance and repair options on the service life of such elements. This report may be accessed by Internet users at However, available publications do not provide reliable procedures for evaluating the existing condition of corrosion-damaged elements or approaches for comparing the effectiveness of maintenance and repair alternatives. Without such information, the selection of the optimum repair strategy cannot be ensured, leading to the application of a less desirable and often more costly repair strategy. Thus, research was needed to identify suitable procedures for assessing the condition of corrosion-damaged bridge elements, estimating the expected remaining service life of such elements, and determining the effects of maintenance and repair options on their service life. Relevant background information was provided by Michigan State University under NCHRP Project 18-6; subsequent work and manual development was performed under NCHRP Project 18-6A. Under NCHRP Project 18-6A, “Service Life of Corrosion-Damaged Reinforced Concrete Superstructure Elements,” CONCORR, Inc., of Sterling, Virginia, was assigned the objective of developing a manual, for consideration and adoption by AASHTO, that provides step-by-step procedures for (1) assessing the condition of reinforced concrete bridge superstructure elements subjected to corrosion-induced deterioration, (2) predicting the remaining service life of such elements, and (3) quantifying the service life extension for such elements expected from alternative maintenance and repair options. The research was limited to concrete bridge superstructure elements reinforced only with epoxy-coated and/or “black” reinforcing steel and did not include prestressed concrete elements or concrete elements reinforced with other steel types. To accomplish this objective, the researchers performed the following tasks: 1. Developed a protocol for condition assessment of reinforced concrete bridge superstructure elements; 2. Developed a model for corrosion initiation for use in projecting future damage; 3. Developed a model for estimating expected remaining service life that incorporated the concept of Susceptibility Index––an approach for interpreting the distribution of chloride ions in the concrete; 4. Presented the remaining service life estimation process as computational software in the form of a Visual Basic–driven Excel spreadsheet to facilitate use; 5. Conducted tests on three bridges and used the results in modeling the corrosion process and in validating the model’s ability to project future deterioration; 6. Provided guidance on the service life that may be attainable with different corrosion control, repair, and rehabilitation techniques; and 7. Organized relevant information in the form of a manual to facilitate use by practitioners. The manual presented herein provides a systematic approach for assessing the condition of corrosion-damaged reinforced concrete bridges and comparing the effects of alternative repair strategies on service life; it is recommended for consideration and adoption by AASHTO. The research agency’s final report contains the data used in the development and validation of the service life model described in this manual; it is not published herein. The report is available on the web as NCHRP Web-Only Document 88 at http://trb.org/news/blurb_detail.asp?id=6150. Also, the computational software (Excel spreadsheet) for the service life estimation process is available on the web at http://trb.org/news/blurb_detail.asp?id=6149 (Author/publisher)
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