Download or read book Cause of Cracking in High Performance Concrete Bridge Decks written by Marco A. Frías and published by . This book was released on 2006 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Transverse Cracking of High Performance Concrete Bridge Decks written by Prakash Ganesh and published by . This book was released on 2006 with total page 125 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, three 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 stresses develop. Additional 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 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 High Performance Concrete Used in New York State Bridge Decks written by Mohammad Hadi Kazemi Kamyab and published by . This book was released on 2008 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phase I Minimization of Cracking in New Concrete Bridge Decks written by Nicole Duffala and published by . This book was released on 2016 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cracking of newly constructed high-performance concrete (HPC) bridges is a problem recognized nationwide and the Nevada Department of Transportation has been plagued with this distress in their HPC concrete bridge decks. This research effort is a strategic attempt to reduce or eliminate random cracking that is caused by restrained shrinkage in new concrete bridge decks constructed in Nevada. The overall objective will be achieved through a three phase research program of which the results of Phase I are being reported in this document. Phase I research findings provide a synthesis of state, regional, and national practices and knowledge on factors contributing to HPC bridge deck cracking. With respect to materials and mixture proportioning, the overwhelming conclusion is that the shrinkage of the concrete mixture, especially at early-ages, must be reduced and the concrete’s resistance to cracking must be Improved. A rigorous, Phase II laboratory experiment was designed and is presented herein. This Phase II laboratory experiment focuses on local materials and will assess the properties of concrete mixtures that are related to early-age drying shrinkage restraint cracking. Ultimately, these research findings could be used to revise standard specifications and special provisions for Nevada DOT bridge decks and eventually reduce the overall incidence of restraint cracking due to concrete drying shrinkage.

Download or read book Controlling Early age Transverse Cracking in High Performance Concrete Bridge Decks written by Eric Ying Xian Liu and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cracking Studies of High performance Concrete for Bridge Decks written by Zhiguo Gong and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessment of Cracking Potential of High performance Concrete Due to Restrained Shrinkage written by and published by . This book was released on 2007 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many State Engineers have observed that a number of high-performance concrete (HPC) bridge decks exhibited cracking and sometimes soon after being poured. Although deck cracking can be attributed to various causes, in many cases, concrete shrinkage is considered the main contributor. Additionally, concrete in bridge decks is considered restrained and there is a need to examine the behavior of HPC mixes under those conditions. The AASHTO test (PP 34-06, The Passive or Restrained Ring Test) is employed to measure the cracking potential and restrained shrinkage behavior of various HPC mixes used in bridge deck projects contracted by the New Jersey Department of Transportation (NJDOT). This thesis presents the results of a study which utilized a method for directly measuring the strain development in the concrete ring using Vibrating Wire Strain Gages (VWSG). For each mix, additional tests were performed to determine the corresponding mechanical properties (e.g., elastic modulus, tensile splitting strength, compressive strength, etc.). The effect of total amount of cementitious materials and the potential of cracking for various mixes are also reported. The results of the study are used to correlate strains from restrained shrinkage tests with those from free shrinkage tests. Results show that the coarse aggregate (CA) content, the coarse/fine aggregate ratio, and cementitious content have the greatest effect on both free and restrained shrinkage. Mixes with higher cementitious content were observed to crack earlier. In general, to minimize HPC cracking potential, it is suggested that a limit on free shrinkage (450 micro strain at 56 days) be specified in bridge decks to indirectly reflect restrained shrinkage conditions. Additional limits for the total amount of coarse aggregate (1800 lb/cu yd.) and Coarse/Fine aggregate ratio (1.48) should also be considered.

Download or read book Field Monitoring of Shrinkage Cracking Potential in a High performance Bridge Deck written by Timothy Walkowich and published by . This book was released on 2011 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past decade many state engineers throughout New Jersey have reported cracking on High Performance Concrete (HPC) bridge decks at early ages. The presence of cracking early in the life of a high performance deck offsets the benefits gained in using the material as the potential for corrosion begins at the onset of cracking. While many factors apply to bridge deck cracking, the shrinkage of the concrete's mass is a primary concern. Because of shear studs and boundary conditions, among other causes that act in restraining the deck itself, it is important to understand the mechanics of concrete under restraint. The AASHTO Passive Ring Test (PP 34-06) is seeing an increase in use in studies analyzing restrained shrinkage. The test simulates a concrete member of infinite length and allows researchers to study the effects of various parameters on restrained shrinkage. This thesis presents the results of a study that analyzed the ring test's ability to simulate restrained shrinkage on HPC bridge decks. The investigation incorporated an instrumented, simply supported composite bridge deck with laboratory samples taken on the day of the pour as well as a finite element analysis. The results suggest the AASHTO Passive Ring Test simulates the restrained shrinkage of simply supported HPC decks reasonably well. Fewer than 1% of all cracking present on the ring specimens saw complete penetration through the sample with 80-90% of all cracking considered to be micro cracking. While the presence of several cracks along the bridge deck itself showed no correlation with the shrinkage ring specimens, finite element analysis suggests these cracks are a result of adjacent live load. Also, the findings of this study highlight the importance of following design in the field as well as the effect of live load on staged construction of HPC bridge decks.

Download or read book Bridge Deck Cracking Evaluation written by and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transverse cracking of concrete bridge decks continues to be an issue for the Montana Department of Transportation (MDT) and is considered a common issue reported among many state departments of transportation (DOTs). In the last 25 years with the introduction of high performance concrete (HPC) in bridge decks to lower permeability and with the use of finer ground cements (to increase early age strength gain and construction schedule), the susceptibility of bridge deck cracking has increased. Cracking commonly leads to a reduction in service life and increased maintenance costs, primarily due to accelerated corrosion of reinforcing steel in the deck. Identifying the causes of bridge deck cracking and providing prevention can be complex and challenging, but is very important for maintaining longevity of the bridge deck. To assist MDT with diagnosing and mitigating the causes of transverse cracking of bridge decks, WJE implemented a multi-disciplinary approach including a literature review, field inspections, bridge deck instrumentation, laboratory evaluations, and finite element modeling (FEM). From this research, WJE found the primary causes were related to non-uniform moisture gradients, drying shrinkage, and specific winter curing procedures. Based on these findings, WJE recommended improvements to mixture proportions, construction practices, and design considerations.

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 A Comparative Study of Shrinkage and Cracking of High Performance Concrete Mixtures for Bridge Decks written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Study on Reduction of Shrinkage Cracks in Bridge Deck Concrete written by Rajesh Anumakonda and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Shrinkage is an unavoidable property of concrete that can lead to cracking, thereby limiting the serviceability of concrete structures. Shrinkage cannot be eliminated but can be minimized. Shrinkage cracking can be a critical problem in concrete construction, especially for flat slab structures such as highway pavements, industrial slab-on-grade, for parking garages, and bridge decks. The primary objective of the research is to evaluate three practical methods to reduce shrinkage cracks in concrete for bridge deck applications. The three methods evaluated are: 1) use of optimized aggregate gradation concrete, 2) use of a new high performance concrete known as low-cracking high performance concrete (LC-HPC) and 3) the use of Fibra Shield Fibers to reduce plastic shrinkage cracking in concrete.

Download or read book Rethinking Bridge Deck Longevity and Maintenance with Portland Cement Polymer Concrete written by Andrew P. Agosto and published by . This book was released on 2008 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridge deck deterioration in the northern Midwest creates significant costs to state Departments of Transportation (DOT's) in the region. The fundamental cause of the problem is low tensile strength and water permeable reinforced concrete resulting in deck cracking and ultimately reinforcing bar corrosion. Portland Cement Polymer Concrete (PCPC) combined with a design approach tailored to its advantages could virtually eliminate early deck deterioration and the associated costs providing an alternative asset management path for bridge decks. Bridge decks would no longer have to be removed from their substructure every fifteen years and replaced. The results would be higher quality, longer lasting bridge decks with lower life cycle costs. This project will demonstrate the feasibility and methodology of such a strategy. This project will develop a strategy that combines innovative concrete materials, novel design and cost analysis that enhances the longevity and reduces the life cycle cost of highway bridge decks. The project is expected to show significant life-cycle cost advantages to using a high performance bridge deck material.

Download or read book Restrained Shrinkage Behavior of High performance Concrete Containing Slag written by John Montemarano and published by . This book was released on 2009 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many high-performance concrete (HPC) bridge decks have been observed to exhibit cracking even after a couple days from casting. The shrinkage of concrete is one of the main causes of why bridge decks crack. Since bridge decks tend to restrain concrete from shrinkage, tensile stresses build up and cause the concrete to crack. Other factors also such as loading cause concrete to crack as well. It is important to test various HPC mixes under restrained conditions to analyze their cracking behavior and severity. The AASHTO test (PP 34-06, The Passive or Restrained Ring Test) is utilized to measure the shrinkage of HPC mixes containing slag under restrained conditions. Cracking patterns are also investigated as well. The use of six Vibrating Wire Strain Gages (VWSGs) have been added in order measure the strain in the concrete ring directly and to detect the actual cracking day. Other tests including the free shrinkage and mechanical properties tests (compressive strength, tensile strength, and elastic modulus) were performed on each mix. The shrinkage performance and cracking behaviors were reported and compared based on total cementitious content, coarse aggregate content, and the coarse aggregate to fine aggregate ratio. It was found that the total cementitious content, coarse aggregate content and its ratio to fine aggregate can significantly affect shrinkage and make that mix more or less likely to crack. Mixes with low coarse aggregate content and highest cementitious content crack the earliest and have the most servere cracking. Mixes with lower cementitious content and a higher coarse aggregate content and ratio tend to crack later and some have a least one ring specimen free of any cracking. Complimentary linear free shrinkage blocks were also tested to correlate the free shrinkage performance with the restrained shrinkage performance of each mix. Any mix with a free shrinkage strain less than 450 microstrains day 56 tends to perform best under restraint conditions. Those mixes contain the lower cementitious contents (less than 700 lbs/cu yd), a higher coarse aggregate content (1800 lbs/cu yd), and a higher coarse aggregate to fine aggregate ratio of 1.6.