Internal Curing of High-performance Concrete for Bridge Decks PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Internal Curing of High-performance Concrete for Bridge Decks PDF full book. Access full book title Internal Curing of High-performance Concrete for Bridge Decks by Jason H. Ideker. Download full books in PDF and EPUB format.
Author: Jason H. Ideker
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 129
Get Book Here
Book Description
High performance concrete (HPC) provides a long lasting, durable concrete that is typically used in bridge decks due to its low permeability, high abrasion resistance, freeze-thaw resistance and strength. However, this type of concrete is highly susceptible to the deleterious effects of both autogenous and drying shrinkage. Both types of shrinkage occur when water leaves small pores, (
Author: Jason H. Ideker
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 129
Get Book Here
Book Description
High performance concrete (HPC) provides a long lasting, durable concrete that is typically used in bridge decks due to its low permeability, high abrasion resistance, freeze-thaw resistance and strength. However, this type of concrete is highly susceptible to the deleterious effects of both autogenous and drying shrinkage. Both types of shrinkage occur when water leaves small pores, (
Author: Timothy J. Barrett
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 483
Get Book Here
Book Description
The Indiana Department of Transportation (INDOT) commissioned the construction of six bridge decks utilizing a new class of internally cured high performance concrete (IC HPC). The first four bridge decks were constructed in the summer of 2013, while the fifth was built in November of 2014 and the sixth is planned for the summer of 2015. These decks implement research findings presented in the FHWA/IN/JTRP-2010/10 report (Schlitter, Henkensiefken, et al. 2010) where internal curing was proposed as one method to reduce the potential for shrinkage cracking, leading to improved durability. In addition, the use of higher performance concrete mixtures and a new specification composed of prescriptive and performance based measures was implemented with the intention of extending the service life of the bridge decks. The objectives of this thesis are to provide documentation of the construction and performance of the IC HPC bridge decks cast in Indiana and provide a viable, practice-ready method for the assessment of the potential durability of these concretes. In fulfillment of these objectives, samples of the IC HPC used in construction were compared to a reference high performance concrete (HPC) which did not utilize internal curing and was made by the same producer with the same constituent materials. The samples collected in the field were transported to the laboratory where the mechanical performance, resistance to chloride ingress, 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. The construction process was documented for first four bridge decks made using internal cured high performance concrete (IC HPC). These concretes were able to be designed, batched, and placed and are now in service. While avoidable issues were observed during batching construction related to corrections of batching water, batching tolerances and fluctuations in air content (which apply to any concrete), the IC HPC was able to be batched and placed using slight modifications to conventional methods. The production of the IC HPC mixtures was implemented using a mixed specification using prescriptive and performance based measures representing an improvement on previous specifications which did not specifically have provisions that consider durability. To aid in the implementation of internal curing in the field, a new quality control technique for lightweight aggregate utilizing a centrifuge has been implemented is now standardized in Indiana Testing Method 222 (Miller, Barrett, et al. 2014). The results of laboratory testing indicate that the compressive strength, modulus of elasticity, and tensile strength of the IC HPC mixtures was not substantially different than the HPC mixtures and as such current codified equations are able to be used to predict the modulus of elasticity and tensile strength if the compressive strength is known. The diffusion of chlorides in these concretes was assessed, where it was shown that each of the mixtures tested had a charge passed in the rapid chloride permeability test of less than 1500 C at 91 days (AASHTO T277-07 2007); additional testing provided equivalent results when performing the Nordtest (NT Build 492 1999), Stadium migration test , or electrical resistivity test. Using experimental results which determined the chloride diffusion and permeability, the diffusion based service life of the IC HPC bridge decks was estimated to be between approximately 60 to 90 years, compared to approximately 18 years for the conventional class C bridge deck concrete used in Indiana. The susceptibility to early age shrinkage and cracking was evaluated where it was shown that IC HPC concretes exhibited a reduction in early age shrinkage of 70 to 90%, resulting in a reduction in residual stresses of 80% or more while reducing thermally induced stress by up to 55% when compared to HPC mixtures. Collectively, these results indicate that the IC HPC mixtures that were produced as a part of this study exhibit the potential of for substantially increased service life while markedly reducing the potential for early age cracking. The second phase of this thesis investigated the role of initial sample conditioning and the effect of changes in degree of saturation on the measured electrical resistivity, where a new function was developed to describe this relationship in air entrained concretes. The consistency and variability in the determination of the chloride diffusion coefficient was investigated through standardized testing methods, where it was shown that the coefficient of variation associated with the accelerated tests was approximately 15% or less and are dependent on the test. Chloride profile measurements made on cores taken from samples which were exposed with a known deicing solution and the temperature fluctuations of West Lafayette, Indiana indicated that on average, the coefficient of variation for determining the apparent chloride diffusion coefficient under is 30% or less. In addition, the use of resistivity measurements on sealed samples was used to evaluate the variability of the concrete produced throughout the construction of the fifth IC HPC bridge deck while comparisons of the samples from the first four bridge decks produced in the laboratory and in the field were also made. The results indicated that the coefficient of variation associated with the resistivity measurements made on the fifth bridge deck was less than 5%, while experimental results indicated that industrial production consistently results in lower performance as measured by the resistivity test when compared to laboratory production. In this study it was also shown that measurements of mechanical properties are not indicative of the potential durability of the concrete. The conclusions of this thesis and the findings presented in the FHWA/IN/JTRP-2010/10 report (Schlitter, Henkensiefken, et al. 2010) and the CDOT-2014-3 report (Jones et al. 2014) indicate that internal curing is a practice-ready, engineered solution that may lead to the production of higher performance concretes which have a reduced potential for cracking. To aid in the implementation of internal curing in practice, spreadsheets which automate calculations necessary for quality control for lightweight aggregates, mixture proportioning, and moisture adjustments have been developed by Miller (2014) and have been made available with the report documenting the construction of the first four bridge decks (Barrett et al. 2015). This thesis also provided the framework for a durability based design approach using sealed electrical resistivity measurements which may be implemented in practice. This method has been shown to be a viable way to rapidly evaluate the chloride diffusion coefficient of concrete and is appropriate for testing large numbers of samples during construction. It is recommended that the approach outlined in this work be implemented in performance based specifications in lieu of other accelerated testing methods which define the performance of the concrete based on the result of that test. Finally, it should be emphasized that the implementation of technologies such as those that are presented in this thesis alone does not guarantee higher performance, as the production of such concrete requires a degree of technical competence in design, production, and construction of concrete materials. As is the case with the production of any concrete, internally cured or not, performance will be directly tied to the careful accounting of water, be it on the surface of aggregates, in the mixing drum after washing, or elsewhere. Special attention should be paid to the proper operation of batching systems, while placement techniques should be reviewed to minimize unwanted effects, and proper finishing and curing techniques must always be practiced. Only after performing the basics of concrete production properly will the full benefits of internal curing be actualized.
Author: Timothy Barrett
Publisher:
ISBN: 9781622603527
Category :
Languages : en
Pages :
Get Book Here
Book Description
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.
Author: Norbert J. Delatte
Publisher:
ISBN:
Category : Bridges
Languages : en
Pages : 148
Get Book Here
Book Description
Early age cracking of bridge decks is a national problem, and may substantially reduce service lives and increase maintenance costs. Cracking occurs when the tensile stress exceeds the tensile strength of the concrete. This is a time-dependent phenomenon, since both the stress and strength change at early ages. Moisture loss increases stress (with increasing shrinkage) and impairs strength gain. Internal curing is one method that has been suggested to reduce early age bridge deck cracking, particularly of concretes with low water to cementitious materials (w/cm) ratios. Many state highway agencies have implemented high performance concrete (HPC) for bridge decks. The low permeability of HPC is used to protect reinforcing steel and prevent corrosion. However, if the concrete cracks, then the protection may be greatly diminished. Transverse cracks due to concrete shrinkage allow water and corrosive chemicals to quickly reach the reinforcing steel causing corrosion and shortening the lifespan of the bridge deck. Reducing shrinkage cracking has been the focus of recent research into mitigation strategies. One unintended consequence of the use of high performance concrete may be early-age cracking. Field studies have shown that, in some cases, high performance concrete bridge decks have cracked less than a year after placement. The use of internal curing to reduce autogenous shrinkage was investigated in this study. One method of internal curing was through the use of coarse aggregates with high absorption capacities. Another method discussed is the use of a partial replacement of the fine aggregate with a structural lightweight aggregate with a very high absorption capacity. Bridge deck cracking is also affected by the nominal maximum size coarse aggregate. The effect on shrinkage with increasing size is discussed. ODOT's District 12, located in Northeastern Ohio, found in an investigation of 116 HPC bridge decks placed between 1994 and 2001 that bridges with little or no cracking used coarse aggregate with an absorption> 1 %, while 75 % of bridges with unacceptable cracking used coarse aggregate with absorption 1 %. This report discusses the laboratory investigation of the field results to determine the better ways to prevent bridge deck cracking-- internal curing or paste reduction by using an aggregate blend. The laboratory investigation found that the strongest effect on cracking was due to the replacement of a small maximum size coarse aggregate with an optimized coarse aggregate gradation. Increasing the coarse aggregate absorption level from
Author: Arman Abdigaliyev
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 89
Get Book Here
Book Description
Author: Alireza Bahadori
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
The construction, crack surveys, and evaluation of 12 bridge decks with internal curing provided by prewetted fine lightweight aggregate and supplementary cementitious materials following internally cured low-cracking high-performance concrete (IC-LC-HPC) specifications of Minnesota or Kansas are described, as well as those from two associated Control decks without IC (MN-Control). Nine IC-LC-HPC decks and one Control deck were monolithic, while three IC-LC-HPC decks and one Control deck had an overlay. The internally cured low-cracking high-performance concrete had paste contents between 23.8 and 25.8 percent by volume. Of the 12 IC-LC-HPC decks, nine were constructed in Minnesota between 2016 and 2020, and three were constructed in Kansas between 2019 and 2021. The performance of the decks is compared with that of earlier IC-LC-HPC bridge decks and low-cracking high-performance concrete (LC-HPC) bridge decks without internal curing. The effects of construction practices on cracking are addressed. The results indicate that the use of overlays on bridge decks is not beneficial in mitigating cracking. The IC-LC-HPC decks constructed exhibited lower average crack densities than those without internal curing. Good construction practices are needed for low-cracking decks. If poor construction practices, which may include poor consolidation and disturbance of concrete after consolidation, over-finishing, delayed application of wet curing, are employed, even decks with low paste contents and internal curing can exhibit high cracking. Delayed curing and over-finishing can also result in scaling damage to bridge decks.
Author: James Lafikes
Publisher:
ISBN:
Category :
Languages : en
Pages : 88
Get Book Here
Book Description
Construction and early-age crack evaluations of four bridge decks in Minnesota placed from 2016 to 2018 that incorporate specifications for Internally-Cured Low-Cracking High-Performance Concrete (IC-LC-HPC) are documented in this study. Two additional decks followed specifications for high-performance concrete and served as controls paired with IC-LC-HPC decks. Pre-wetted fine lightweight aggregate (FLWA) was used to provide a targeted internal curing water content of 8% by total weight of binder. The IC-LC-HPC mixtures included 27 to 30% slag cement by total binder weight while the control mixtures included 25 or 35% Class F fly ash by total weight of binder. For one IC-LC-HPC deck, mixture proportions were modified based on a higher FLWA absorption than originally used to design the mixture. One IC-LC-HPC placement failed due to errors in FLWA moisture corrections and concrete batching that led to rejections of batches, leaving an inadequate supply of material to complete the deck. Crack surveys were completed for the IC-LC-HPC and control decks placed in 2016 and 2017. Crack densities at these ages were low compared to most Low-Cracking High-Performance Concrete decks in Kansas and Internally-Cured High-Performance Concrete decks in Indiana. The only exception was one IC-LC-HPC deck that exhibited extensive cracking within one year after placement, which had an overlay with a high cement paste content and no internal curing. This project serves as a foundation for implementing IC-LC-HPC in upcoming bridge decks in Kansas and Minnesota.
Author: Dejian Shen
Publisher: Springer Nature
ISBN: 9811983984
Category : Technology & Engineering
Languages : en
Pages : 348
Get Book Here
Book Description
This monograph is written based on the author's research on the assessment, control, and repair of cracking of early-age concrete in the recent decade. The technique of internal curing for increasing cracking resistance of early-age concrete is further developed through experimental and theoretical research. It establishes models for predicting the internal relative humidity and autogenous shrinkage of internally cured concrete at early age; reveals the variation law and mechanism of early-age tensile creep of internally cured concrete; and explores the variation law and mechanism of early-age cracking resistance of internally cured concrete under continuous restrained condition or uniaxial restrained condition. It is designed as a reference work for professionals or practitioners and a textbook for undergraduates or postgraduates. As such, this book provides valuable knowledge, useful methods, and practical experience that can be considered in the field of concrete cracking control.
Author: Tengfei Fu
Publisher:
ISBN:
Category : High strength concrete
Languages : en
Pages : 109
Get Book Here
Book Description
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: John Schlitter
Publisher:
ISBN: 9781622600311
Category :
Languages : en
Pages :
Get Book Here
Book Description
