Download or read book Evaluating Free Shrinkage of Concrete for Control of Cracking in Bridge Decks written by Swapnil Deshpande and published by . This book was released on 2007 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Alternative Materials to Control Drying shrinkage Cracking in Concrete Bridge Decks written by and published by . This book was released on 2003 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Shrinkage Cracking Potential of Concrete Used in Bridge Decks in Florida written by and published by . This book was released on 2005 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of innovation materials to control restrained drying shrinkage cracking in concrete bridge decks written by Michael Douglas Brown and published by . This book was released on 2002 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design Methods for the Control of Restrained Shrinkage Cracking written by Robert J. Frosch and published by . This book was released on 2006-09-15 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Concrete Mix Designs to Mitigate Early age Shrinkage Cracking in Bridge Decks written by Jianmin Zhuang and published by . This book was released on 2009 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mitigation Strategies for Early age Shrinkage Cracking in Bridge Decks written by Pizhong Qiao (Civil engineer) and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Early-age shrinkage cracking has been observed in many concrete bridge decks in Washington State and elsewhere around the U.S. The cracking increases the effects of freeze-thaw damage, spalling, and corrosion of steel reinforcement, thus resulting in premature deterioration and structural deficiency of the bridges. In this study, the main causes of the early-age cracking in the decks are identified, and concrete mix designs as a strategy to prevent or minimize the shrinkage cracking are evaluated. Different sources (eastern and western Washington) and sizes of aggregates are considered, and the effects of paste content, cementitious materials (cement, fly ash, silica fume, slag), and shrinkage reducing admixture (SRA) are evaluated. A series of fresh, mechanical and shrinkage property tests were performed for each concrete mix. The outcomes of this study identify optimum concrete mix designs as appropriate mitigation strategies to reduce or eliminate early-age shrinkage cracking and thus help minimize shrinkage cracking in the concrete bridge decks, potentially leading to longer service life.
Download or read book Evaluation of Shrinkage Cracking Potential of Concrete Used in Bridge Decks in Florida written by Rajarajan Subramanian and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: From the test data and the analysis results obtained from the 15 concrete mixes tested in this set of experiments, the developed Constrained Long Specimen method demonstrated that it provided reasonable assessment of expected shrinkage-induced stresses in the concrete. Due to the creep of concrete at early age, the shrinkage-induced stress in the concrete is much lower than that estimated by multiplying the shrinkage strain by the elastic modulus of the concrete. Using the CLS test method enables the creep component to be properly considered, and a realistic determination to be made of the expected induced shrinkage stresses in concrete in service. The results of the CLS tests on the 15 concrete mixes showed the possible benefits of using a shrinkage-reducing admixture in reducing the potential shrinkage cracking of concrete in service.
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 Review and Specification for Shrinkage Cracks of Bridge Decks written by Jafar Allahham and published by . This book was released on 2016 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: An existing standard method ASTM C157 is used to determine the length change or free shrinkage of an unrestrained concrete specimen. However, in bridge decks, the concrete is actually under restrained conditions, and thus free shrinkage test methods do not represent the same condition of bridge decks and are not correlated to in field bridge deck shrinkage. An alternative for restrained shrinkage is to use one of the two existing standards AASHTO T334-08 or ASTM C1581. In these two restrained test methods, the concrete is cast in the circumference around an inner steel ring. The purpose of this study was to construct the apparatus for the AASHTO T334-08 method to estimate the cracking age of concrete mixtures that may be used in bridge decks. In the processes of the apparatus setup, several limitations to the method were discovered, such as the influence of the surrounding environment and the repeatability of the method. Thus, an additional study was done to evaluate the sensitivity of shrinkage measurements (ASTM C157 and AASHTO T334-08) in different surrounding environments, with different mix designs (e.g., varying w/cm, binder content and aggregate size), and different concrete specimen thicknesses. Overall, it was confirmed that most mixtures did not even indicate any cracking unless a high cement volume content of 24% with no coarse aggregates was tested using the existing AASHTO T334-08 restrained ring method. A thinner ring (2” of concrete instead of 3”) had a decreased age of cracking. The free shrinkage ASTM C157 is still the easiest, and a relatively fast method to use and can provide relative comparisons between different mixtures or between different environments.
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 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 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 Mitigation Strategies for Early age Shrinkage Cracking in Bridge Decks written by Pizhong Qiao and published by . This book was released on 2010 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Early-age shrinkage cracking has been observed in many concrete bridge decks in Washington State and elsewhere around the U.S. The cracking increases the effects of freeze-thaw damage, spalling, and corrosion of steel reinforcement, thus resulting in premature deterioration and structural deficiency of the bridges. In this study, the main causes of the early-age cracking in the decks are identified, and concrete mix designs as a strategy to prevent or minimize the shrinkage cracking are evaluated. Different sources (eastern and western Washington) and sizes of aggregates are considered, and the effects of paste content, cementitious materials (cement, fly ash, silica fume, slag), and shrinkage reducing admixture (SRA) are evaluated. A series of fresh, mechanical and shrinkage property tests were performed for each concrete mix. The outcomes of this study identify optimum concrete mix designs as appropriate mitigation strategies to reduce or eliminate early-age shrinkage cracking and thus help minimize shrinkage cracking in the concrete bridge decks, potentially leading to longer service life.
Download or read book Evaluation of Concrete Deck Curing Regimens Using Capillary Pressure Sensing System written by Samuel Spann and published by . This book was released on 2019 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Early-age plastic shrinkage cracking is a common problem with the construction of concrete bridge decks due to the high surface area-to-volume ratio and exposure to potentially detrimental environmental effects. Curing regimens are utilized to mitigate cracking risk during the plastic stage of the concrete; the curing regimens evaluated for this study were wet burlap-polyethylene sheeting, two acrylic curing compounds, and one lithium compound. Capillary pressure in the water filled pores has been shown to correlate to the plastic shrinkage cracking risk of concrete. A new portable system has been developed to measure the capillary pressure that could potentially be used in the field on fresh bridge deck concrete. Individual test slabs were performed to test the curing regimens using the capillary pressure sensor system (CPSS). The system contains multiple sensors that contain pressure transducers that measure the capillary pressure changes during the plastic stage. Overall, wet burlap-polyethylene sheeting was shown to be the most effective curing regimen, with the lithium curing compound performing similarly to the control slab with no curing regimen applied. Both acrylic compounds were shown to perform comparatively well, completely mitigating early-age plastic shrinkage cracking in some instances, and allowing small shrinkage cracks to form in others. While the CPSS exhibited the ability to show when cracking occurred in most cases, the magnitude of the capillary pressure at which plastic shrinkage cracks formed varied significantly across tests.
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 Bridge Deck Concrete Volume Change written by Andrei Ramniceanu and published by . This book was released on 2010 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete structures such as bridge decks, with large surface area relative to volume, shrink and crack, thus reducing service life performance and increasing operation costs. The project evaluated the early, first 24 hours, and long-term, 180 days, shrinkage of Virginia Department of Transportation overlay and A4 general bridge deck concrete mixtures. A modified ASTM C157 prism was developed to measure the early-age shrinkage, as was a unique hygral cylinder test. Long-term shrinkage was measured using the ASTM C157 prism test. In addition, scaled bridge deck overlay specimens were cast to assess cracking potential. Overlay mixtures tested were latex modified mixtures using portland cement, Type K cement, an expansive mixture and portland cement, fly ash and microsilica blend. Deck concrete mixtures evaluated were fly ash, slag, Type K cement and an expansive mixture. Recommendations for controlling shrinkage at 3, 7, and 28 days were developed for all overlay and A4 concrete mixtures.
