Effects of Liquid Nitrogen on Concrete Properties PDF Download
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Author: Maria C. G. Juenger
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 67
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Book Description
Author: Maria C. G. Juenger
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 67
Get Book Here
Book Description
Author: Maria C. G. Juenger
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 124
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Book Description
Author: John Hema
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 454
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Book Description
Controlling the placement and hydration temperature of concrete is important to concrete durability. Thermal gradients and delayed ettringite formation (DEF) result in cracking when concrete in the plastic state becomes too hot. Cooler placement temperatures slow hydration reaction, increase working time, reduce the maximum temperature in the concrete member, and reduce thermal gradients. Furthermore, cooler concrete achieves better long-term strength and microstructural development. Concrete producers have been using multiple methods of reducing the placement temperature of concrete, such as cooling mixtures with ice or chilled water, shading aggregate piles, placing concrete at night, and using evaporative cooling of aggregate piles. More recently, concrete producers have turned to liquid nitrogen for cooling fresh concrete. The objective of this research was to determine the effects of liquid nitrogen on concrete hydration, microstructural development, and performance. The following concrete mixture properties and methods were investigated: cement type, the effects of selected supplementary cementing materials and chemical admixtures, placement temperature, and the time at which liquid nitrogen dosing occurs (delayed dosing). Concrete performance was tested in terms of slump, setting time, yield, compressive and splitting tensile strength, elastic modulus, rapid chloride permeability, and hardened and fresh air void analysis. Hydration and microstructural development were monitored by isothermal calorimetry, semi-adiabatic calorimetry, x-ray diffractometry, inductively coupled plasma, and environmental scanning electron microscopy. Additional testing was performed on concrete mixing drums to determine the effects of liquid nitrogen on the durability of steel mixing drums. The results indicate that performance, hydration, and microstructural development of fresh concrete are relatively unaffected when cooled with liquid nitrogen to room temperatures. Significant findings show that the slump of liquid nitrogen cooled concrete is similar to hot concrete mixtures and not room temperature mixtures. Additionally, setting time results show that liquid nitrogen dosing of hot concrete can be delayed for up to 1 hour and setting times will still be similar to room temperature mixtures. Based on findings from this research study, liquid nitrogen is recommended as a primary cooling option to reduce the placement temperature of fresh concrete.
Author: Eduardo M.R. Fairbairn
Publisher: Springer
ISBN: 3319766171
Category : Technology & Engineering
Languages : en
Pages : 432
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Book Description
This book provides a State of the Art Report (STAR) produced by RILEM Technical Committee 254-CMS ‘Thermal Cracking of Mas-sive Concrete Structures’. Several recent developments related to the old problem of understanding/predicting stresses originated from the evolution of the hydration of concrete are at the origin of the creation this technical committee. Having identified a lack in the organization of up-to-date scientific and technological knowledge about cracking induced by hydration heat effects, this STAR aims to provide both practitioners and scientists with a deep integrated overview of consolidated knowledge, together with recent developments on this subject.
Author: Sonia Marie Solt
Publisher:
ISBN:
Category :
Languages : en
Pages : 368
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Book Description
This study investigated the effects and use of liquid nitrogen for cooling concrete. In the past, ice and chilled water have been the mainstays to cool concrete for mass pours in which the concrete must be a specified temperature as required by the Texas Department of Transportation (TxDOT). Cooling the concrete prevents large thermal gradients from developing between the core of the concrete and the outer layer of the concrete caused by the cement hydration reaction. Preventing these large thermal differences directly affects thermal cracking and thus concrete durability. Liquid nitrogen has been actively used to cool concrete in projects all over the world, and is becoming increasingly popular. However, the various effects of LN on concrete have not been studied in depth and assembled into a published document. This thesis covers basic safety precautions and methods of injecting liquid nitrogen which were documented and recorded by conducting surveys and visiting sites in Austin, Texas where LN was in use. In addition, lab experiments were conducted to study the effects of LN on setting time, admixtures, and drying shrinkage. The results of these tests are reported in this thesis.
Author: Waterways Experiment Station (U.S.)
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 60
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Book Description
Author: I. Soroka
Publisher: CRC Press
ISBN: 0203473639
Category : Architecture
Languages : en
Pages : 251
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Book Description
Elevated temperatures are known to affect the properties of both fresh and hardened concrete. This book describes in detail these effects and explains the mechanisms involved with particular reference to their practical aspects.
Author: Committee on Nonconventional Concrete Technologies for Renewal of the Highway Infrastructure
Publisher: National Academies Press
ISBN: 0309562317
Category : Technology & Engineering
Languages : en
Pages : 125
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Book Description
Nonconventional Concrete Technologies: Renewal of the Highway Infrastructure identifies research and development opportunities in innovative, nonconventional materials and processes that have the potential to accelerate the construction process, improve the durability of highway pavement and bridges, and enhance the serviceability and longevity of new construction under adverse conditions.
Author: FIB – International Federation for Structural Concrete
Publisher: FIB - International Federation for Structural Concrete
ISBN: 0727702572
Category : Technology & Engineering
Languages : en
Pages : 24
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Book Description
Author: J. Marchand
Publisher: CRC Press
ISBN: 0203627091
Category : Architecture
Languages : en
Pages : 323
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Book Description
Concrete durability in climates where freezing and thawing occurs is a continuing problem. It is particularly acute for highway and bridge structures, where de-icing salts are used to combat the effects of frost, snow and ice. These salts can cause damage to concrete and accelerate corrosion of reinforcements. This book presents the latest international research on this area, with contributions from North America and Europe which were presented at an international RILEM workshop.
