Download or read book Predicting Service Life of Concrete Bridge Decks Subject to Reinforcement Corrosion written by PD. Cady and published by . This book was released on 1992 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The deterioration of the nation's highway infrastructure is proceeding at an alarming rate. A major element of the problem involves chloride-induced corrosion of reinforcing steel in concrete bridge components. In order to rationally implement bridge management strategies, it is generally recognized that life-cycle cost analyses of viable alternatives are required. This necessitates the development of reliable means for predicting the service lives of alternative procedures. The major components of a rational model for predicting service life in this scenario center on the time for the chloride ion concentration to reach the corrosion threshold level at reinforcement locations and the corrosion reaction time necessary to produce loss of serviceability. Obviously, the definition of the terminal serviceability in terms of deterioration level also constitutes an important element of the model. This paper examines a semi-empirical deterioration model for predicting service life based on fundamental concepts, augmented with historical data.

Download or read book Bridge Service Life Design written by Elizabeth Rose Bales and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: High costs and traffic disruption associated with the deterioration of reinforced concrete bridge decks because of corrosion have sparked renewed interest in service life design. Reinforced concrete bridge decks are exposed to chlorides from deicing salts; when the chlorides reach the steel reinforcement, they initiate corrosion. This study supports the adoption of the methodology described in fib Bulletin 34, Model Code for Service Life Design, for reinforced concrete bridge decks in Virginia. Concrete mixture properties and environmental exposure conditions were characterized. Values particular to regions within Virginia and suggested default values were identified and organized in a database to support the development of service life design guidelines. The predicted service life for eight bridge decks using low-cracking concrete and corrosion-resistant reinforcement (VDOT Reinforcement Class I, MMFX, ASTM 1035) was evaluated. The service life model was also implemented in a life-cycle cost analysis for a case study bridge, which found superior reliability of corrosion-resistant reinforcement from a life-cycle perspective. In addition to supporting the implementation of service life design, several investigations identified key assumptions and variables in the service life model and identified critical areas for future characterization. The partial differential equation for apparent chloride diffusion was solved with both an approximate analytical approach and a numerical approach. Delays in the application of deicing salt were investigated using the numerical approach, and a ramp-type function for surface chloride concentration was explored using the analytical approach. Aging coefficients based on curing were also considered. A sensitivity analysis identified the aging coefficient and the surface chloride concentration as the most critical variables. The study concluded that sufficient data are available to implement the fib Model Code for Service Life Design, but that caution in interpreting results is warranted because of the high uncertainty associated with the most critical variables. According to the results of the service life analyses, the regional climatic variability and differences in mix design across Virginia indicate that a "one-size-fits-all" approach to bridge deck specifications may not be appropriate. The use of corrosion-resistant steel and low-cracking concrete mixtures can provide a substantial (greater than 100 years) bridge deck service life

Download or read book Bridge Deck Service Life Prediction and Costs written by and published by . This book was released on 2007 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: The service life of Virginia's concrete bridge decks is generally controlled by chloride-induced corrosion of the reinforcing steel as a result of the application of winter maintenance deicing salts. A chloride corrosion model accounting for the variable input parameters using Monte Carlo resampling was developed. The model was validated using condition surveys from 10 Virginia bridge decks built with bare steel. The influence of changes in the construction specifications of w/c = 0.47 and 0.45 and w/cm = 0.45 and a cover depth increase from 2 to 2.75 inches was determined. Decks built under the specification of w/cm = 0.45 (using slag or fly ash) and a 2.75 inch cover depth have a maintenance free service life of greater than 100 years, regardless of the type of reinforcing steel. Galvanized, MMFX-2, and stainless steel, in order of increasing reliability of a service life of greater than 100 years, will provide a redundant corrosion protection system. Life cycle cost analyses were conducted for polymer concrete and portland cement based overlays as maintenance activities. The most economical alternative is dependent on individual structure conditions. The study developed a model and computer software that can be used to determine the time to first repair and rehabilitation of individual bridge decks taking into account the time for corrosion initiation, time from initiation to cracking, and time for corrosion damage to propagate to a state requiring repair.

Download or read book Corrosion Forms and Control for Infrastructure written by Victor Chaker and published by ASTM International. This book was released on 1992 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: Twenty-five papers originally presented at the ASTM symposium held in San Diego, Calif., November 1991, provide innovative, successful techniques for the practicing engineer, scientist, and others involved with corrosion control for infrastructure. Practical experiences and applications as well as n

Download or read book Relating Material Properties to Exposure Conditions for Predicting Service Life in Concrete Bridge Decks in Indiana written by Vinit Barde and published by Purdue University Press. This book was released on 2007-12-01 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridges in the US are deteriorating at an alarming rate. It has been estimated that transportation agencies across the US invest more than 5 billion dollars on concrete bridge repair and renovation annually. To meet the needs of transportation industry, high performance concrete (HPC) has been developed for the construction of bridges. However, the link between material properties and field performance is not completely established. Goodspeed et al. [1996] defined the performance of concrete using four material parameters that describe durability and four material parameters that describe mechanical properties. However, material properties alone cannot entirely define field performance. Rather some consideration is needed to quantify the conditions to which the concrete will be exposed. The exposure conditions vary based on the geographical location. This work relates material properties with the exposure conditions typical of those in the state of Indiana to estimate the performance of concrete bridge decks. The exposure conditions in the state of Indiana were assessed. Specifically, temperature, rainfall, wetting events, freeze thaw cycles, and relative humidity have been classified. To assess the variation in these parameters across the state, contour maps were developed using information from cities in the state of Indiana as well as cities in surrounding states. The eight parameters suggested by Goodspeed et al. [1996] were reviewed. Three key distresses behavior (chloride ingress, freezing and thawing, and shrinkage cracking) have been investigated in depth. Relationships have been developed to relate measured material properties (from the results of AASHTO/ASTM tests) with the predicted performance of the concrete structure under different exposure condition. First, a model is presented that relates the results of Rapid Chloride Permeability Test (RCPT) with the anticipated service life of bridge deck against corrosion due to chloride ingress. Second, a model is presented that relates results of sorptivity, porosity, and critical saturation with the anticipated service life of concrete exposed to freezing and thawing. Third, a model is presented that relates the shrinkage of concrete with the potential for premature cracking. The results of each of the models have been presented for conditions that are typical of the state of Indiana.

Download or read book Models for Predicting Corrosion induced Cracking Spalling delamination of Rehabilitated Rc Bridges Decks written by Kai Zhou and published by . This book was released on 2005 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Service Life of Corrosion damaged Reinforced Concrete Bridge Superstructure Elements written by and published by . This book was released on 2006 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary product of this effort was the development of a manual titled "Manual on Service Life Prediction of Corrosion-Damaged Reinforced Concrete Bridge Superstructure Elements." This manual provides a protocol for assessing the condition of reinforced concrete bridge superstructure elements subjected to corrosion-induced deterioration, predicting the remaining service life of such elements using the developed service life model, and quantifying service life extension for such elements expected from alternative maintenance and repair options. This report documents the data utilized in the development and validation of the service life model presented in the manual.

Download or read book Manual on Service Life of Corrosion damaged Reinforced Concrete Bridge Superstructure Elements written by Ali Akbar Sohanghpurwala and published by Transportation Research Board. This book was released on 2006 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Finite Element Analysis of Corrosion induced Cracking Spalling and Delamination of RC Bridge Decks written by and published by . This book was released on 2005 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The corrosion of reinforcing steel in reinforced concrete (RC) bridge decks due to the application of de-icing salts in winter has been recognized as one of the major causes of highway bridge deterioration in North America. Corrosion-induced damage is usually manifested by longitudinal cracking, spalling, and/or delamination of the concrete cover due to the expansion of corrosion products accumulating around the reinforcement. This damage leads to reduction or loss of serviceability, safety, and service life of RC bridge decks. This paper presents finite element analyses of the behaviour of the concrete bridge deck cover subjected to reinforcing steel corrosion. The prediction of the damage caused by corroding reinforcing bars is established by calculating the induced stresses in the surrounding concrete. The numerical model is used to conduct a parametric investigation of several design variables. It is found from the analyses that different failure mechanisms govern depending on the geometry and configuration of the reinforcing bars in the concrete cover of the bridge deck. Finally, the impact of concrete overlays on the governing failure modes of cracking, spalling and/or delamination of the concrete cover is investigated by using the model.

Download or read book Probabilistic Chloride Corrosion Service Life Model Validation written by G. Williamson and published by . This book was released on 2009 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deterioration of steel reinforced concrete bridge decks by chloride induced corrosion in North America is of major concern. Chloride from applications of sodium, calcium, and magnesium chloride during winter maintenance operations initiates corrosion, which subsequently spalls the reinforcing steel cover concrete. Initial service life prediction models were diffusion based deterministic/empirical models, which significantly overestimate service lives. Probabilistic solutions provided more realistic estimates. However, chloride corrosion service life models for reinforced concrete elements have not been sufficiently validated against actual field performance. The objective of this study was to validate a probabilistic model using field survey data from ten bridge decks built in Virginia. Field surveys included damage assessments as the sum of spalls, delaminations, and patches. Damage surveys were conducted initially and 3 years later. Chloride content and clear concrete cover depth surveys were conducted to establish cover depth, surface chloride concentration, and chloride diffusion constant global variations. Validation comparisons were performed considering the ten decks as representative of a construction era and as individual decks. Results demonstrated that the probabilistic model accurately predicts global performance but not individual deck performance. Damage predictions of individual decks were greater than and less than the field assessed condition. Differences ranged from an overestimate of 64 years to an underestimate of 11 years. Underestimates averaged 14 years and overestimates averaged 43 years. The large overestimates of 44, 62, and 64 years occurred for estimated service lives of 80-100 years. Insufficient number of model input parameters of surface chloride and particularly the diffusion constant is the plausible reason for the lack of prediction accuracies for the individual decks.

Download or read book Service Life Prediction of Protective Systems for Concrete Bridge Decks in Alberta written by and published by . This book was released on 1994 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reliable life cycle calculations for bridge maintenance management depends upon having reasonable alternative choices for deck repair or replacement, accurate costs for those alternative choices, and accurate service life predictions for each of the alternate choices. The objective of this study was to develop a series of tools, based on existing performance condition surveys, that can be used to better establish the expected and remaining service life of protective systems during life cycle evaluations. The study has identified two deterioration mechanisms which affect service life: 1) delamination of the concrete deck resulting from corrosion of reinforcement and 2) debonding of a concrete overlay. These deterioration mechanisms are described, influencing factors discussed and various definitions presented. The study develops a relationship between the extent of early corrosion induced deterioration and area of deck that is actively corroding, as measured by half cell potentials. A time relationship for the area of deck that is actively corroding is then presented, which permits the user to establish service life. The study also presents an evaluation of expected time to develop overlay debonding based on various types of bridge structures.

Download or read book Durability of Concrete Bridge Decks written by and published by . This book was released on 1965 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Life cycle Cost Analysis for Protection and Rehabilitation of Concrete Bridges Relative to Reinforcement Corrosion written by Ronald L. Purvis and published by Strategic Highway Research Program (Shrp). This book was released on 1994 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: A systematic methodology is presented for highway agencies to use at the project level to determine the most cost-effective treatment, and its timing, for specific concrete bridge components that are deteriorating or are subject to deterioration. The methodology is set forth in the form of both a handbook and a computer program. The methodology in its present form applies only when the predominant concrete deterioration is associated with chloride-induced corrosion of the reinforcing steel. The methodology is designed to be flexible and can be tailored to suit the needs of individual highway agencies.

Download or read book Assessment and Rehabilitation Strategies guidelines to Maximize the Service Life of Concrete Structures written by Teresa M. Adams and published by . This book was released on 2002 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Identification of Performance Indicators and Development of Performance Based Specifications for Bridge Decks written by Thomas H. Wenzel and published by . This book was released on 2000 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigating Causes and Determine Repair Needs to Mitigate Falling Concrete from Bridge Decks written by Nabil F. Grace and published by . This book was released on 2012 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study developed a procedure to identify concrete bridge decks that are exhibiting the characteristics associated with falling concrete. Field exploratory work on reinforced concrete bridge decks was supported by analytical and laboratory investigations. The field work included visual inspection, non-destructive tests, and sampling of full-depth cores and powder samples from the bottom of the bridge deck. Chief variables assessed were the chance of corrosion by the half-cell potential, chloride content at the location of the bottom reinforcement, and the concrete pH level. The chloride diffusivity was estimated from the chloride profile. The laboratory investigation was performed on bridge deck beams. The beams were constructed from concrete containing chloride levels known to cause corrosion as well as from a control concrete. Beams were subjected to freeze-thaw or saltwater followed by repeated loading to simulate field conditions. The following characteristics were quantified: chance of corrosion, corrosion rate, chloride content, flexural response as a function of environmental exposure and repeated loads, and ultimate strength. The size of the porous zone around the reinforcement was determined using an environmental scanning electron microscope. Finally, a strategy was developed to assess if a bridge deck exhibited the characteristics associated with falling concrete. The strategy included visual inspection of cracking and spalling, assessment of chance of corrosion, chloride content, and pH levels. If any of these measures exceed critical levels a service life calculation needs to be performed. Based on existing mathematical models, the time to corrosion initiation and time to corrosion cracking can be predicted. The resulting time is then compared to the age of the bridge. From this information proper planning for future repair needs can be made.

Download or read book A Bibliography on the Corrosion and Protection of Steel in Concrete written by E. Escalante and published by . This book was released on 1979 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: