Shrinkage Study Of High Performance Concrete For Bridge Decks PDF Download
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| Author | : Tengfei Fu |
| Publisher | : |
| Total Pages | : 109 |
| Release | : 2013 |
| Genre | : High strength concrete |
| ISBN | : |
Download Shrinkage Study of High Performance Concrete for Bridge Decks Book in PDF, ePub and Kindle
In the field of civil infrastructure, bridge desks are typically constructed using high performance concrete (HPC). Concrete bridge decks demand qualities such as low permeability, high abrasion resistance, superior durability, and long design life. Over decades of field and laboratory experience, many HPC bridge decks have been found to be susceptible to shrinkage and subsequent cracking, which is regarded as a significant cause for premature deterioration, increased maintenance costs and even structural deficiency. Appropriate shrinkage limits and standard laboratory/field tests that allow proper criteria to ensure crack resistant HPC are not clearly established either in the technical literature or in specifications. A comprehensive study is presented in this dissertation on shrinkage and shrinkage induced cracking in HPC, with four main objectives: 1) mitigate the shrinkage and cracking issues in HPC using internal curing by fine lightweight aggregate (FLWA) and/or incorporation of shrinkage reducing admixture (SRA); 2) improve the standard ASTM chemical shrinkage test method for HPC systems containing supplementary cementitious materials (SCMs) and/or SRA; 3) modify existing drying shrinkage models mainly the ACI 209 model to predict long-term drying shrinkage for modern HPC concrete by using short-term experimental measurements; 4) complete a state-of-the-art literature review on shrinkage and cracking issues in HPC bridge decks. One of the most significant research findings is a proposed "cracking potential indicator" (CPI) that uses only the free shrinkage and mechanical properties of HPC. This was correlated to standard restrained ring tests.
| Author | : |
| Publisher | : |
| Total Pages | : |
| Release | : 2002 |
| Genre | : Bridges |
| ISBN | : |
Download A Comparative Study of Shrinkage and Cracking of High Performance Concrete Mixtures for Bridge Decks Book in PDF, ePub and Kindle
| Author | : Robert J. Frosch |
| Publisher | : Purdue University Press |
| Total Pages | : 178 |
| Release | : 2008-11-01 |
| Genre | : Transportation |
| ISBN | : 9781622601080 |
Download High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study, Volume 1: Structural Behavior Book in PDF, ePub and Kindle
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.
| Author | : Kejin Wang |
| Publisher | : |
| Total Pages | : 0 |
| Release | : 2013 |
| Genre | : |
| ISBN | : |
Download Investigation Into Shrinkage of High-Performance Concrete Used for Iowa Bridge Decks and Overlays Book in PDF, ePub and Kindle
High-performance concrete (HPC) overlays have been used increasingly as an effective and economical method for bridge decks in Iowa and other states. However, due to its high cementitious material content, HPC often displays high shrinkage cracking potential. This study investigated the shrinkage behavior and cracking potential of the HPC overlay mixes commonly used in Iowa. In the study, 11 HPC overlay mixes were studied. These mixes consisted of three types of cements (Type I, I/II, and IP) and various supplementary cementitious materials (Class C fly ash, slag and metakaolin). Limestone with two different gradations was used as coarse aggregates in 10 mixes and quartzite was used in one mix. Chemical shrinkage of pastes, free drying shrinkage, autogenous shrinkage of mortar and concrete, and restrained ring shrinkage of concrete were monitored over time. Mechanical properties (such as elastic modulus and compressive and splitting tensile strength) of these concrete mixes were measured at different ages. Creep coefficients of these concrete mixes were estimated using the RILEM B3 and NCHRP Report 496 models. Cracking potential of the concrete mixes was assessed based on both ASTM C 1581 and simple stress-to-strength ratio methods. The results indicate that among the 11 mixes studied, three mixes (4, 5, and 6) cracked at the age of 15, 11, and 17 days, respectively. Autogenous shrinkage of the HPC mixes ranges from 150 to 250 microstrain and free dying shrinkage of the concrete ranges from 700 to 1,200 microstrain at 56 days. Different concrete materials (cementitious type and admixtures) and mix proportions (cementitious material content) affect concrete shrinkage in different ways. Not all mixes having a high shrinkage value cracked first. The stresses in the concrete are associated primarily with the concrete shrinkage, elastic modulus, tensile strength, and creep. However, a good relationship is found between cementitious material content and total (autogenous and free drying) shrinkage of concrete.
| Author | : Timothy Barrett |
| Publisher | : |
| Total Pages | : |
| Release | : 2015-09-01 |
| Genre | : |
| ISBN | : 9781622603527 |
Download Documentation of the INDOT Experience and Construction of the Bridge Decks Book in PDF, ePub and Kindle
The Indiana Department of Transportation (INDOT) constructed four bridge decks utilizing internally cured, high performance concrete (IC HPC) during the summer of 2013. These decks implement research findings from the research presented in the FHWA/IN/JTRP-2010/10 report where internal curing was proposed as one method to reduce the potential for shrinkage cracking, leading to improved durability. The objective of this research was to document the construction of the four IC HPC bridge decks that were constructed in Indiana during 2013 and quantify the properties and performance of these decks. This report contains documentation of the production and construction of IC HPC concrete for the four bridge decks in this study. In addition, samples of the IC HPC used in construction were compared with a reference high performance concrete (HPC) which did not utilize internal curing. These samples were transported to the laboratory where the mechanical properties, resistance to chloride migration, and potential for shrinkage and cracking was assessed. Using experimental results and mixture proportions, the diffusion based service life of the bridge decks was able to be estimated. Collectively, the results indicate that the IC HPC mixtures that were produced as a part of this study exhibit the potential to more than triple the service life of the typical bridge deck in Indiana while reducing the early age autogenous shrinkage by more than 80% compared to non-internally cured concretes.
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| Publisher | : |
| Total Pages | : 112 |
| Release | : 2006 |
| Genre | : Concrete |
| ISBN | : |
Download Transverse Cracking of High Performance Concrete Bridge Decks After One Season Or Six to Eight Months Book in PDF, ePub and Kindle
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.
| Author | : Mateusz Radlinski |
| Publisher | : Purdue University Press |
| Total Pages | : 254 |
| Release | : 2008-11-01 |
| Genre | : Transportation |
| ISBN | : 9781622601097 |
Download High-Performance Concrete Bridge Decks: A Fast-Track Implementation Study, Volume 2: Materials Book in PDF, ePub and Kindle
The purpose of this research was to examine the applicability of ternary binder systems containing ordinary portland cement (OPC), class C fly ash (FA) and silica fume (SF) for bridge deck concrete. This was accomplished in two parts, the laboratory part and a field application part. During the laboratory studies, four ternary mixtures, each containing either 20% or 30% FA and either 5% or 7% SF were subjected to four different curing regimes (air drying, 7 days curing compound application and 3 or 7 days wet burlap curing). In general, all four ternary mixtures exhibited very good water and chloride solution transport-controlling properties (resistance to chloride-ion penetration, chloride diffusivity and rate of water absorption). However, it was concluded that in order to ensure adequate strength, good freezing and thawing resistance, satisfactory resistance to salt scaling, and adequate shrinkage cracking resistance the FA content should not exceed 20%, SF content should not exceed 5% (by total mass of binder) and paste content should be kept below 24% by volume of concrete. Further, wet burlap curing for a minimum of 3 days was required to achieve satisfactory performance and to obtain a reliable assessment of in-situ compressive strength (up to 28 days) using maturity method. The second part of this research examined the performance of ternary concrete containing 20% FA and 5% SF in the pilot HPC bridge deck constructed in northern Indiana. Using maturity method developed for the purpose of this study, it was determined that the unexpectedly high RCP values of concrete placed late in the construction season were mostly attributed to low ambient temperature. Additional applications of the developed maturity method were also demonstrated. These include assessment of risk of scaling and reduction in time to corrosion initiation as a function of construction date, as well as estimation of long-term RCP values of concrete subjected to accelerated curing.
| Author | : Timothy Walkowich |
| Publisher | : |
| Total Pages | : 107 |
| Release | : 2011 |
| Genre | : Bridges |
| ISBN | : |
Download Field Monitoring of Shrinkage Cracking Potential in a High-performance Bridge Deck Book in PDF, ePub and Kindle
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.
| Author | : |
| Publisher | : |
| Total Pages | : 504 |
| Release | : 2009 |
| Genre | : Concrete |
| ISBN | : |
Download Development and Construction of Low-cracking High-performance Concrete (LC-HPC) Bridge Decks Book in PDF, ePub and Kindle
The development and evaluation of low-cracking high-performance concrete (LC-HPC) for use in bridge decks is described based on laboratory test results and experience gained during the construction of 14 bridges. This report emphasizes the material aspects of the construction process; a companion report will provide a detailed discussion of the construction, design, and environmental factors affecting the performance of LC-HPC bridge decks. The KU Mix design methodology for determining an optimized combined gradation uses the percent retained chart and the Modified Coarseness Factor Chart. The process begins by developing an ideal gradation followed by the determination of an optimum blend of user-selected aggregates. A Microsoft® Excel workbook enhanced with Visual Basic for Applications is available to perform the optimization process at www.iri.ku.edu. The second portion of the study involves evaluating the effect of paste content, water-cement (w/c) ratio, coarse aggregate type, mineral admixture type (silica fume, slag cement, and Class F fly ash each at two levels of replacement), cement type and fineness, a shrinkage reducing admixture, and the duration of curing on the free-shrinkage characteristics of concrete mixtures in the laboratory tested in accordance with ASTM C 157. The final portion of the study presents the specifications, construction experiences, and the preliminary evaluation of 14 LC-HPC bridge decks that have been built or are planned in Kansas. The techniques used to reduce cracking in these bridge decks are presented, and the field experiences for the 18 individual LC-HPC placements completed to date are presented. The results indicate that LC-HPC decks with an optimized aggregate gradation and design w/c ratios of 0.44 and 0.45 with cement contents of 317 and 320 kg/m3 (535 and 540 lb/yd3) have more than adequate workability, finishability, and pumpability, in addition to reduced cracking. A preliminary evaluation of these decks indicates that, on average, the LC-HPC decks are performing at a level approximately equal to or exceeding the best performing monolithic decks in Kansas surveyed over the past 15 years.
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| Publisher | : |
| Total Pages | : 146 |
| Release | : 2007 |
| Genre | : Concrete |
| ISBN | : |
Download Assessment of Cracking Potential of High-performance Concrete Due to Restrained Shrinkage Book in PDF, ePub and Kindle
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.
