Behavior of the reinforced concrete at cryogenic temperatures (original) (raw)
Related papers
A review of concrete properties at cryogenic temperatures: Towards direct LNG containment
Construction and Building Materials, 2013
This paper provides a "state-of-the-art" review of the pertinent properties of concrete at temperatures lower than -165°C that make it amenable for direct containment of liquefied natural gas (LNG). In addition, the paper presents a brief historical and economic perspective on cryogenic concrete. The permeability, coefficient of thermal expansion (CTE), tensile strain capacity and bond strength to reinforcement are discussed in light of key factors controlling them, including moisture content, aggregate type, etc. Moreover, the effects of cryogenic freeze-thaw cycles on thermal deformation of concrete are highlighted. Generally, the permeability and the CTE are lower while the tensile strain capacity and bond strength to reinforcement are greater for concrete at cryogenic temperatures versus concrete at ambient temperatures. It is concluded that more work is necessary to fully understand thermal dilation and damage growth in concrete due to differential CTE of its components, in order to facilitate development of design methodologies that might be employed to mitigate the associated risks in its eventual utilization for direct LNG containment. This is an author-created version: regkogbara@cantab.net (RB Kogbara). A definitive version was subsequently published at http://dx. This is a state-of-the-art review of concrete properties at cryogenic temperatures.
Procedia Structural Integrity, 2020
The current development of Liquid Natural Gas (LNG) storage site requires a thorough analysis of concrete behaviour under cryogenic temperatures. Indeed, this kind of infrastructure is based on a set of tanks that presents several layers. The first one is the cryogenic steel tank that directly contains the LNG. An outer concrete box represents the external layer and usually between these two layers there is a thermal insulating material. A leak from the steel tank can apply a tremendous thermal gradient to the concrete external layer. Thus, the study of concrete behaviour in this situation is important and few studies are available for concrete characterized by lightweight clay aggregate. In this experimental work, the variation of the modulus of elasticity of lightweight clay aggregate concrete, due to temperature gradients have been analyzed and discussed. A set of concrete cubes has been immersed in liquid nitrogen to reach-180°C, then they have been tested under compressive stress measuring both stress and strains. Correlations between elastic properties and temperatures are proposed.
Effect of Freezing-Thawing Cycles on the Physical and Mechanical Characteristics of Concrete
2010
Concrete is the most used construction material in practically all of civil engineering fields due to its economical and technical advantages. However, its microstructure is porous and may be completely or partially water saturated. In severely cold climates, this water freezes and degradations develop gradually with the freezing-thawing cycle’s number, in forms of internal cracking, chipping and scaling. Frost behaviour is based on the coupling between the 9% volumetric increase during water transformation into ice, the cryo-suction phenomena, the non frozen water transport within the porous network and the thermo-mechanical behaviour of each component of the frozen media. It is thus obvious that the frost resistance depends on the microstructure (pore size distribution and permeability) and the mechanical characteristics of the material. In this paper, physical and mechanical characteristics evolution during freezing-thawing cycles was followed. The results show that the reduction...
Effect of freezing-thawing on concrete behavior
Challenge Journal of Concrete Research Letters, 2018
This study aims to determine the effect of change of temperature (freezing-thawing cycles) on the behavior of the mortar and the concrete. Also, the evaluation of the effect of air entering for improving the durability of the mortar and concrete was discussed. 23 mixes were cast to evaluate the purpose of this study. Cement types (Portland cement and limestone cement), aggregate types (dolomite and gravel), dosages of air entering 0.01, 0.1, 0.15 and 0.2% of cement weight and freezing thawing cycles (50, 100, 150, 200, 300 and 400 cycles) were considered. Relative dynamic modules of elasticity which is illustrated the internal cracks growth, durability factor and losses of weight were evaluated. Empirical correlations were formulated. The results showed that; 0.15% air entrained of cement weight improve the durability in term of freezing-thawing; where the durability factor for the mixes was ≥ 85% that exposed to freezing-thawing cycles in range 0-200. Up to 200 cycles of freezing-t...
Freezing and Thawing Durability of Very High Strength Concrete
American Journal of Engineering and Applied Sciences, 2011
Problem statement: The newly developed Very High Strength Concrete (VHSC), having compressive strengths of 29 ksi and flexural strengths of 6 ksi, represents a breakthrough in concrete technology. Study to further enhance the properties of this new concrete is continuing. Approach: The objective of this study is to investigate the effect of exposing Very High Strength Concrete (VHSC) specimens to rapid freeze/thaw cycles. Twenty one specimens were tested according to the Standards of the American Society for Testing and Materials ASTM C215, ASTM C666 and ASTM C78. Results: One hundred freeze/thaw cycles were performed on the VHSC specimens. Change in specimen's dimensions and material's properties were recorded at zero, forty, seventy and one hundred cycles. Dimensions and properties considered were: dimension of cross section, length, weight, Dynamic Moduli, Poisson's Ratio, durability factor and Modulus of Rupture. Conclusion/Recommendations: The test results indicated that VHSC is good freeze-thaw resistance (durability factor > 85%) and can avoid freeze/thaw damage. Freeze-thaw cycling did not significantly affect VHSC specimens' cross sectional dimensions, length, or Poisson's Ratio. However, there was a decrease in the specimens' weight with the increase in number of freeze/thaw cycles, but the decrease was very slim indicating little or no deterioration has occur. Moreover, the fine voids exist in VHSC greatly lower the freezing point of any trapped water, making the material less susceptible to Freeze-Thaw damage.
Freeze-Thaw Resistance of Concrete: Effect of: Curing Conditions, Moisture Exchange and Materials
2001
Research on freeze-thaw resistance of concrete in general and on curing and moisture conditions in particular is motivated from an economic and product sustainability point of view. Specifically, it is argued for the importance of considering the effect of curing and test exposure conditions on the moisture uptake and performance during freeze-thaw. Due to the demonstrated importance of moisture conditions on performance, they should be related to those of field service conditions when choosing a test procedure in a particular case. This is vital for adequate testing of newand more sustainable concrete materials.
Nordic Concrete Research
A one-day Nordic Concrete Research workshop on “Accelerated freeze-thaw testing of concrete” attracted approx. 30 participants. The workshop included presentations on various aspects, such as observed frost damage in the field and the importance of the temperature curve during testing as well as other interactions with the surroundings of the concrete. The workshop also included examples of recent research, which can improve our knowledge about the frost damage mechanism and therefore provide input to improving the standardised test methods. The present paper is a summary of the nine presentations and the discussion arising from the presentations.
2009
The aim of the present study is to investigate the effect of low-permeability concrete, made with reduced water‐to‐binder ratios (w/b) and/or supplementary cementitious materials (SCMs), on the need for air entrainment to achieve freezing‐thawing (F‐T) durability. In the present study, concrete mixes were made with different types of cement (Types I and IP), with or without fly ash replacement (15%), with different water‐to‐binder ratios (w/b =0.25, 0.35, 0.45 and 0.55), and with or without air entraining agent (AEA). All concrete mixtures were controlled to have a similar slump by using different dosages of superplasticizer. The rapid chloride permeability and F-T durability of the concrete samples were determined according to ASTM C1202 and ASTM C666A, respectively. The air void structure of the concrete was studied using the Air Void Analyzer, RapidAir, and porosity tests (ASTM C642). In addition, the general concrete properties, such as slump, air content, unit weight, and 28‐da...