Download or read book Quantification of Cracks in Reinforced Concrete Bridge Decks written by Saikrishna Ganapuram and published by . This book was released on 2013 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cracking in reinforced concrete bridge decks is a widespread concern in the United States. Many concrete bridge decks, regardless to the age of construction, have shown different levels and patterns of cracking. Not only does cracking of bridge decks weaken the bridge infrastructure, but also allows the inflow of corrosive agents into the reinforcement, regardless of the bridge design type, length of spans, deck thickness and concrete mixture designs. Increased cracking of concrete bridge decks all over the world poses a threat to life as well as prove extremely expensive for repair and maintenance. Thus, precautions must be taken in order to avoid and restrict bridge deck cracking, one of which is inspection of the bridge at regular intervals. The Ohio Department of Transportation's current procedure for bridge inspection offers only a qualitative assessment of the bridges inspected. In this study, a method was developed for the quantification of crack densities for twelve bridges in District 3. Two types of bridges were inspected: three structural slab bridge decks and nine stringer supported bridge decks. Crack densities for each bridge were determined based on crack maps corresponding to the surveys for each bridge deck. Results indicated that structural slab bridge decks have slightly higher shrinkage crack densities compared to the bridge decks constructed with stringer supports. However, the "structural" cracks seem to be wider than shrinkage cracks for structural slabs (greater than 0.007 inch). Particularly on bridge ASD-42-0656, which is a continuous slab bridge, there were several large "structural" cracks that were parallel to the pier beams supports. The shrinkage crack densities of the twelve bridge decks determined in this study were considerably lower than the crack densities of similar bridge decks located in other states, demonstrating that Ohio bridge decks in general have lower crack density than those in other states. The shrinkage crack densities of the bridges constructed with QC/QA type of concrete have lower values than the bridges made with other types of concrete. Also, the crack widths were determined at certain key locations and were compared with theoretical values. The measured crack widths are much larger compared to the corresponding theoretical crack widths. This is a reason for concern.
Download or read book Concrete Bridge Deck Performance written by H. G. Russell and published by Transportation Research Board. This book was released on 2004 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: At head of title: National Cooperative Highway Research Program.
Download or read book Cracking in Concrete Bridge Decks written by Tony R. Schmitt and published by . This book was released on 1995 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: The causes of cracking in bridge decks are investigated and procedures are recommended to alleviate the problem. Forty continuous steel girder bridges, thirty-seven composite and three noncomposite bridges are evaluated. Field surveys conducted to document cracking patterns and to determine the crack density of each bridge are described. Information collected from construction documents, field books, and weather data logs is presented and compared to the observed levels of cracking to identify correlations between cracking and the variables studied. Thirty-one variables are considered such as material properties, site conditions, construction procedures, design specifications, age of bridge and traffic volume. Based on the research reported herein, cracking in monolithic bridge decks increases with increasing values of concrete slump, percent volume of water and cement, water content, and compressive strength, and decreasing values of air content (especially below 6.0%). Bridge deck overlays placed with zero slump concrete consistently exhibit high levels of cracking. Cracking in overlays also increases as placement lengths increase. High maximum air temperatures and large changes in air temperature on the day of casting aggravate cracking in monolithic bridge decks. High average air temperatures and large changes in air temperature similarly aggravate cracking in bridge deck overlays. Both monolithic and two layer bridges with fixed-ended girders exhibit increased cracking near the abutments compared to those with pin-ended girders.
Download or read book Quantification of Cracks in Concrete Bridge Decks in Ohio District 3 written by Sai Ganapuram and published by . This book was released on 2012 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of cracks in reinforced bridge decks is a critical problem, not only in Ohio state, but the whole of United States. Many bridge decks constructed within the last 10 years in Ohio have already shown varying levels and patterns of cracking. Bridge deck cracking is a serious issue because cracks allow harmful and corrosive chemicals to penetrate the concrete and deteriorate the reinforcing steel embedded in it, regardless of the bridge design type, length of spans, deck thickness and concrete mixture designs. Proper precautions need to be taken to avoid rapid deterioration of the bridges which can lead to increased maintenance costs and the need for possible replacement. The Ohio Department of Transportation's current procedure for bridge inspection requires periodic surveying of the whole bridge. However, this inspection procedure offers only a qualitative assessment of the bridges inspected. In this study, a quantitative measurement strategy was adopted by measuring the crack densities of twelve bridges in District 3. Two types of bridges were inspected: three structural slab bridge decks and nine stringer supported bridge decks. Crack densities were determined based on crack maps corresponding to the surveys for each bridge deck. The crack densities determined for the twelve bridge decks indicated that structural slab bridge decks have slightly higher shrinkage crack densities compared to the bridge decks constructed with stringer supports. However, the "structural" cracks seem to be wider for structural slabs (greater than 0.007 inch). Particularly on bridge ASD-42-0656, which is a continuous slab bridge, there were several large "structural" cracks that were parallel to the intermediate supports. These cracks were very wide (much greater than 0.007 inch). The shrinkage crack densities of the twelve bridge decks determined in this study were considerably lower than the crack densities of similar bridge decks located in other states, demonstrating that Ohio bridge decks in general have lower crack density than those in other states. The shrinkage crack densities of the bridges constructed with QC/QA type of concrete have lower values than the bridges made with other types of concrete.
Download or read book Transverse Cracking of High Performance Concrete Bridge Decks After One Season Or Six to Eight Months written by and published by . This book was released on 2006 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cracking is a major problem with newly placed concrete decks. These decks tend to develop full depth, transverse cracks and partial depth longitudinal cracks within a few months of the concrete being placed. A literature review showed that several other states had experienced similar problems. A review of data from Ohio bridge decks showed weak correlations between deck cracking and slump, time of year when the deck was placed, shrinkage, chloride permeability and compressive strength, but there was no clear relationship between cracking and any of these properties. Data also suggested that using a coarse aggregate with an absorption> 1% may help mitigate deck cracking but will not always stop it. As part of this study, 3 bridge decks were instrumented. One was a standard class "S" concrete deck and the other two were high performance concrete. The class "S" deck showed only hairline cracking after 1 year, but transverse cracking occurred in the HPC decks. Instruments were placed in the decks to monitor strains. From the data, it appears that cracking is caused by several factors. High heat of hydration caused the plastic concrete to expand. When the concrete sets and cools, tensile stressed develop. Further tensile stresses develop through drying shrinkage. Restraining the deck against normal thermal movement contributes to additional tensile stress. Autogeneous shrinkage, where high heats of hydration cause water evaporation during hydration, and plastic shrinkage may cause more tensile stress. Recommendations for mitigating cracking include using lower cement contents, adding pozzolans and retarders, using slightly higher water/cement ratios, using larger aggregates, taking steps to limit shrinkage and eliminating restraints.
Download or read book Cause and Control of Transverse Cracking in Concrete Bridge Decks written by M. Ala Saadeghvaziri and published by . This book was released on 2002 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many concrete bridge decks develop transverse cracking and most of these cracks develop at early ages, some right after construction and some after the bridge has been opened to traffic for a period of time. Structural design factors have not been the subject of much research in the past and they were the main thrust of this research study. Using 2-D and 3-D linear and nonlinear finite element models many design factors such as girder stiffness, deck thickness, girder spacing, relative stiffness of deck to girder, amount of reinforcements, etc., were studied. The research study also included a comprehensive review of the existing literature as well as survey of 24 bridges in the state of New Jersey. Results of each research task are presented and discussed in detail. Furthermore, based on analytical results and literature review, the effect of various factors are quantified and specific recommendations for possible consideration in design are made.
Download or read book High Performance Concrete Bridge Decks A Fast Track Implementation Study Volume 1 Structural Behavior written by Robert J. Frosch and published by Purdue University Press. This book was released on 2008-11-01 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transverse cracking of concrete bridge decks is problematic in numerous states. Cracking has been identified in the negative and positive moment regions of bridges and can appear shortly after opening the structure to live loads. To improve the service life of the bridge deck as well as decrease maintenance costs, changes to current construction practices in Indiana are being considered. A typical bridge deck was instrumented which incorporated the following: increased reinforcement amounts, decreasing reinforcement spacing, and high-performance, low-shrinkage concrete. The low shrinkage concrete was achieved using a ternary concrete mix. The objective of this research was to determine the performance, particularly in terms of transverse cracking and shrinkage, of a bridge incorporating design details meant to reduce cracking. Based on measurements from the bridge, it was determined that maximum tensile strains experienced in the concrete were not sufficient to initiate cracking. An on-site inspection was performed to confirm that cracking had not initiated. The data was analyzed and compared with the behavior of a similarly constructed bridge built with nearly identical reinforcing details, but with a more conventional concrete to evaluate the effect of the HPC. Based on this study, it was observed that full-depth transverse cracks did not occur in the structure and that the use of HPC lowered the magnitude of restrained shrinkage strains and resulting tensile stresses.
Download or read book Investigation of Cracking in Concrete Bridge Decks at Early Stages written by Stanislav Milos Dekic and published by . This book was released on 1996 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Layout of a Protocol for the Field Performance of Concrete Deck and Crack Sealants written by José Antonio Pincheira and published by . This book was released on 2009 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main objective of this project was to develop and layout a protocol for the long-term monitoring and assessment of the performance of concrete deck and crack sealants in the field. To accomplish this goal, a total of six bridge decks were chosen for study. The decks have ages that vary from 4 to 30 years old, are all in good condition, though some presented a variety of longitudinal, transverse and diagonal cracking. In each deck, test segments were laid out along one lane in four of the six bridges. Drill powder samples were extracted in each segment in order to determine the in-situ, near-surface chloride ion content of the deck. Laboratory analyses of the samples showed that the chloride ion content varied between 3.2 lb/cy for the younger decks (3 years old) and 20.8 lb/cy for the older decks (28 years old). Based on the recommendations of a previous laboratory investigation, a pool of the best performing deck and crack sealants were selected to be applied in the decks. In two bridges, deck segments were sealed with four deck sealants while one segment was left unsealed to be used as a control segment. Additionally, the cracks in each of these segments were sealed with five crack sealants. While two other decks were also scheduled for sealing as part of this phase of the project, they were not done because the required curing time for some of the products was longer than deemed acceptable by DOT crews for these high traffic bridges. It is recommended, however, that every effort be made to have these decks be sealed in the near future. The remaining two bridges had been sealed at the time of construction. While no specific information could be secured about the product used in these decks, the low chloride ion content in these decks suggested that the applied product has helped reduce the ingress of chloride ions. Therefore, it is recommended that these decks continue to be monitored over time. Based on the inspections and the data collected in the field, a protocol and schedule for the continuing monitoring of sealant performance is presented.
Download or read book Cracking in Bridge Decks written by Pui-shum B. Shing and published by . This book was released on 1999 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the findings of a study whose primary objectives are to determine the cause of extensive transverse cracking that has been observed in some existing bridge decks, and to identify the change of material specifications and construction practice that is necessary to reduce the severity of deck cracking. To achieve these goals, recent studies on the cause of bridge deck cracking were reviewed, an experimental study was conducted to compare the shrinkage properties of different concrete mixes, and the current material and design specifications and construction practice adopted by the Colorado Department of Transportation (CDOT) were reviewed to identify areas that need improvement. A survey was conducted on seven newly constructed bridges to examine the extent of cracking in concrete decks that were constructed with the different mix designs and curing procedure that were currently used by CDOT.
Download or read book Transverse Cracking in Newly Constructed Bridge Decks written by Paul D. Krauss and published by . This book was released on 1996 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cracks in Concrete Bridge Decks written by D. Campbell-Allen and published by . This book was released on 1978 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Factors Affecting the Durability of Concrete Bridge Decks written by M. W. Horn and published by . This book was released on 1972 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Early Age Shrinkage and Cracking of Nevada Concrete Bridge Decks written by Heinere Howard Ah-Sha and published by . This book was released on 2001 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reducing Cracks in Concrete Bridge Decks Using Shrinkage Reducing Admixture written by Harikrishnan Nair and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Restrained shrinkage cracking of concrete bridge decks creates a significant durability problem. Major admixture suppliers in the United States have introduced a new category of chemical admixtures called shrinkage reducing admixtures (SRAs). SRAs work by reducing the surface tension of pore water and thereby decreasing the capillary stress and shrinkage induced by drying. Several studies have reported that using SRAs in concrete mixtures is one of the most effective ways of reducing shrinkage cracking. The purpose of this study was to investigate the effectiveness of SRAs in reducing drying shrinkage in Virginia Department of Transportation (VDOT) concrete mixtures and thus reducing cracks in bridge decks. Nine bridges located in VDOT's Northern Virginia, Staunton, and Fredericksburg districts were selected for study. Three different SRA products were used. With the exception of one mixture, the maximum cementitious content was limited to 600 lb/yd3. Fresh and hardened concrete properties were determined for each mixture, and field placement details were documented. The results showed that low cementitious concrete with SRA was effective in minimizing bridge deck cracking. The study showed that bridges with fewer and narrower cracks or no cracks can be constructed and that proper construction practices are needed to reduce bridge deck cracking. The study recommends the use of SRA with a lower cementitious content in VDOT bridge deck concrete mixtures. A VDOT special provision was developed for the future use of SRA in concrete mixtures.
Download or read book Control and Repair of Bridge Deck Cracking written by Robert J. Frosch and published by . This book was released on 2010-11-15 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reducing Cracks in Concrete Bridge Decks Using Shrinkage Reducing written by Harikrishnan Nair and published by . This book was released on 2016 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Restrained shrinkage cracking of concrete bridge decks creates a significant durability problem. Major admixture suppliers in the United States have introduced a new category of chemical admixtures called shrinkage reducing admixtures (SRAs). SRAs work by reducing the surface tension of pore water and thereby decreasing the capillary stress and shrinkage induced by drying. Several studies have reported that using SRAs in concrete mixtures is one of the most effective ways of reducing shrinkage cracking. The purpose of this study was to investigate the effectiveness of SRAs in reducing drying shrinkage in Virginia Department of Transportation (VDOT) concrete mixtures and thus reducing cracks in bridge decks. Nine bridges located in VDOT Northern Virginia, Staunton, and Fredericksburg districts were selected for study. Three different SRA products were used. With the exception of one mixture, the maximum cementitious content was limited to 600 lb/yd3. Fresh and hardened concrete properties were determined for each mixture, and field placement details were documented. The results showed that low cementitious concrete with SRA was effective in minimizing bridge deck cracking. The study showed that bridges with fewer and narrower cracks or no cracks can be constructed and that proper construction practices are needed to reduce bridge deck cracking. The study recommends the use of SRA with a lower cementitious content in VDOT bridge deck concrete mixtures. A VDOT special provision was developed for the future use of SRA in concrete mixtures.
