Study on Influence of Freeze-Thaw for Chlorion Penetration

2014 ◽  
Vol 578-579 ◽  
pp. 1295-1298
Author(s):  
Zhen Qiang Wang ◽  
Ya Na Zhang ◽  
Yan Liu
Keyword(s):  
Concrete Strength ◽  
Chloride Ion ◽  
Plain Concrete ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Chloride Diffusivity ◽  
Chloride Ion Penetration ◽  
Freezing And Thawing Cycles ◽  
Relationship Of ◽  
The Relationship

Freeze-thaw cycles can affect the chloride diffusivity of concrete to a certain extend. The experimental study of plain concrete specimens with different strength grade were carried out, suffering 0, 50, 100 and 150 cycles of freeze-thaw. Chloride ion penetration under different strength, different cycle-index and the concrete mass-loss caused by freeze-thaw cycles are analyzed. Using this method the relationship of chlorion permeability with concrete strength is established when the concrete specimens reach to a particular value of freezing and thawing cycles.

Finite Element Analysis for Concrete Damage under Freeze-Thaw Action

2009 ◽  
Vol 417-418 ◽  
pp. 133-136 ◽  
Author(s):  
Ji Ze Mao ◽  
Hong Ye Wang ◽  
Zhi Yuan Zhang ◽  
Zong Min Liu
Keyword(s):  
Finite Element ◽  
Dynamic Modulus ◽  
Damage Mechanics ◽  
Concrete Strength ◽  
Failure Surface ◽  
Surface Model ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Finite Element Software ◽  
The Relationship

Freeze-thaw damage is one of the most representative damages in concrete durability. Commonly, freezing and thawing tests are conducted to investigate the freeze-thaw resistance of concrete, and the loss of dynamic modulus of concrete is regarded as the failure criterion. However, the research on the evolution of concrete strength during the damage process is still not enough when subjected to freezing and thawing. In this study, the concrete freeze-thaw deterioration was considered as isotropic elastic damage, and relative variation functions of dynamic modulus and Poisson’s ratio with freeze-thaw cycles were set up. Based on damage mechanics, the Ottosen failure surface model with four parameters was established to indicate the relationship between the concrete freeze-thaw failure surface and freeze-thaw cycles. Then the four-parameter failure surface model was set into ADINA finite element software program for secondary development to investigate the strength properties of concrete component under freeze-thaw action. The relationship between load and deflection of concrete was analyzed and simulated after 0, 25 and 50 freeze-thaw cycles. The simulated and experimental results are basically identical, which demonstrates that this finite element simulation is a feasible way to analyze and evaluate the performance of concrete structures in cold regions.

Chloride Ion Diffusion Behavior of Concrete after Freezing and Thawing Cycles

2013 ◽  
Vol 671-674 ◽  
pp. 1652-1656 ◽  
Author(s):  
Feng Qu ◽  
Di Tao Niu
Keyword(s):  
Chloride Transport ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Chloride Diffusion ◽  
Ion Diffusion ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Improved Model ◽  
Freezing And Thawing Cycles ◽  
Chloride Ion Diffusion

With repeated action of freeze-thaw cycles, chloride ion diffusion characteristics changed obviously in concrete structure. In the study, the chloride ion diffusion coefficient and the surface chloride ion concentration were discussed especially with the trends. Based on these facts, the chloride diffusion model and the improved model of concrete was also discussed based on its time-dependent characteristics, which indicated that the freeze-thaw damage of concrete would have a greater impact to the chloride transport course in the concrete, and so on the service life of concrete structures would be affected.

Study of Frost Resistance on Air-Entrained Concrete in Sulfated Medium

2006 ◽  
Vol 302-303 ◽  
pp. 125-130 ◽  
Author(s):  
Ge Yong ◽  
Yuan Jie ◽  
Wen Cui Yang ◽  
Bao Sheng Zhang
Keyword(s):  
Fresh Water ◽  
Frost Resistance ◽  
Plain Concrete ◽  
Sulfate Solution ◽  
Test Results ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Freezing And Thawing Cycles ◽  
Air Entrained Concrete ◽  
Sodium Solution

Frost resistance of plain concrete and air-entrained concrete subjected to freeze-thaw cycles in fresh water and 5 % and 7 % sodium sulfate solution are investigated in this paper. The test results show that the frost resistance of concrete is different in the different medium. The properties of concrete frozen in 5 % and 7 % sodium solution are different from that in fresh water, and entraining air into concrete properly can increase the frost resistance significantly whether in fresh water or in sulfate solution. Higher strength concrete could resist the degradation of freezing and thawing cycles in water, but some of them failed suddenly in midspan of specimens under the sulfate solution.

Experimental investigation on bond strength between BFRP bars and concrete under freeze-thaw cycles

2021 ◽  
pp. 002072092199659
Author(s):  
Xiao-Yong Wu ◽  
Kai Zhou ◽  
Xiao-Lu Yuan ◽  
Yong-Shuai Zhu ◽  
Pei Fan ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Bond Strength ◽  
Concrete Strength ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Thawing Cycle ◽  
Pull Out ◽  
The Times ◽  
Freezing And Thawing Cycles ◽  
Ultimate Bond Strength

To investigate the bond strength between BFRP bars and concrete under freezing and thawing cycles, a total of 36 specimens for freezing and thawing cycles tests and center pull-out tests were carried out with different times of freezing and thawing cycles (0, 10, 20, and 40 times) and different concrete strength grades (C30, C35, and C40). The results of this study showed that the specimens without freezing and thawing cycle (0 times) and specimens of C30 with freeze-thaw for 40 times were pulled out, and the remaining specimens were split. With the increase of the concrete strength grade, the debonding strength increases gradually and the ultimate bond strength does not increase in proportion. The debonding strength of BFRP bars and concrete decreases gradually with the times of freezing and thawing cycles. The ultimate bond strength and peak slip indicated a trend of increasing and then decreasing with the increasing times of freezing and thawing, while the peak slip of specimens of C30 with 40 times freeze-thaw increases slightly.

Review of Strength and Failure Criteria for Concrete After Freeze-Thaw Damage

2012 ◽  
Vol 253-255 ◽  
pp. 456-461
Author(s):  
Yan Fu Qin ◽  
Bin Tian ◽  
Gang Xu ◽  
Xiao Chun Lu
Keyword(s):  
Normal State ◽  
Concrete Strength ◽  
Failure Criteria ◽  
Concrete Durability ◽  
Freezing And Thawing ◽  
Normal Concrete ◽  
Strength Criteria ◽  
Freeze Thaw ◽  
Ordinary Concrete ◽  
Concrete Failure

Frost resistance research is one of the important subject of concrete durability, however strength criteria is an important part of the study of mechanical behavior of concrete. So far, about concrete failure criteria are almost for normal concrete, which the domestic and overseas scholars have comparative detailed research in every respect to it, and to freeze-thaw damage of concrete but few research. Based on the summary of the existing ordinary concrete strength and failure criteria in normal state and after freeze-thaw damage，this paper have a brief comment of failure criteria on concrete after freeze-thaw damage. For later research about concrete strength and failure criteria under freezing and thawing cycle provide the reference.

Permeability and volume changes in till due to cyclic freeze/thaw

1998 ◽  
Vol 35 (3) ◽  
pp. 471-477 ◽  
Author(s):  
Peter Viklander
Keyword(s):  
Soil Structure ◽  
Void Ratio ◽  
Vertical Direction ◽  
Rigid Wall ◽  
Freezing And Thawing ◽  
Volume Changes ◽  
Freeze Thaw ◽  
Fine Grained ◽  
Loose Soil ◽  
Freezing And Thawing Cycles

A fine-grained nonplastic till was compacted in the laboratory in three types of rigid wall permeameters, having a volume of 0.4, 1.5, and 25 dm3, respectively, and, was thereafter exposed to a maximum of 18 freezing and thawing cycles. The permeabilities in the vertical direction of saturated samples were measured in unfrozen soil as well as in thawed soil. The results show that the permeabilities changed after freezing and thawing. The magnitude of the changes in this study were in the range 0.02-10 times after freeze/thaw compared with the unfrozen soil. Soil exhibited volume changes subsequent to freeze/thaw. The volume typically decreased for an initially loose soil and increased for a dense soil. Independent of whether the initial soil structure was loose or dense, a constant "residual" void ratio, eres, was obtained after 1-3 cycles. For the soil investigated, the residual void ratio ranged from 0.31 to 0.40.Key words: till, fine-grained, non plastic, permeability, freeze/thaw, residual void ratio.

scholarly journals Water Loss during Contracture of Muscle

1962 ◽  
Vol 46 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Benjamin Kaminer
Keyword(s):  
Smooth Muscle ◽  
Water Loss ◽  
Significant Loss ◽  
Frog Muscle ◽  
Tetanic Stimulation ◽  
Force Of Contraction ◽  
Freezing And Thawing ◽  
Microscopic Studies ◽  
Relationship Of ◽  
The Relationship

The relationship of contracture and exudation of water in frozenthawed frog muscle was studied. With maximum shortening, there was a water loss of 35 per cent of the weight of muscle. By restricting the contraction, it was demonstrated that the amount of water loss was proportional to the degree of shortening, there being no significant loss with isometric contraction. Muscle already shortened by tetanic stimulation also exuded water on subsequent freezing and thawing. The force of contraction could be reduced by depleting the muscle of calcium and it was shown that the amount of water exuded was also proportional to the tensile ability of the muscle. In a smooth muscle (anterior byssus retractor of Mytilus) which did not contract vigorously only a little water exuded. Contracture produced by caffeine was similarly associated with a loss of water. Microscopic studies revealed a disruption of the sarcomeres of the frozen-thawed muscle which contracted; glycerol-extracted and calcium-depleted muscles, which did not contract on freeze-thawing, did not show such disruption. Freezing and thawing of actomyosin caused a reversible syneresis of the protein. It is concluded that the exudation of the water is not merely due to the freezing and thawing but is also dependent on the contractile events.

Engineering properties of rubberized concrete

1992 ◽  
Vol 19 (5) ◽  
pp. 912-923 ◽  
Author(s):  
Neil N. Eldin ◽  
Ahmed B. Senouci
Keyword(s):  
Plain Concrete ◽  
Crumb Rubber ◽  
Engineering Properties ◽  
Unit Weight ◽  
Rubberized Concrete ◽  
Portland Cement Concrete ◽  
Freezing And Thawing ◽  
Scrap Tire ◽  
Plastic Energy ◽  
Freezing And Thawing Cycles

Growing piles of discarded tires are potential sources of fire and health hazards. The current disposal methods are wasteful and costly. As a possible solution to the problem of scrap-tire disposal, an experimental study was conducted to examine the potential use of rubber aggregate (tire chips and crumb rubber) as mineral aggregate substitute in Portland cement concrete mixes. The research focused on determining the strength characteristics of rubberized concrete and examined the relationship between the size, percentage, and shape of rubber aggregate and the strength measured.Rubberized concrete was found to possess good esthetics, acceptable workability, and a smaller unit weight than plain concrete. However, it exhibited low compressive and tensile strengths and lower resistance to repeated freezing and thawing cycles than that of plain concrete. A statistical analysis of the experimental data suggested that only the percentage by volume of rubber in the mix has a significant effect on strength. The size and shape was found insignificant. Unlike plain concrete, rubberized concrete did not demonstrate the typical brittle failure. It exhibited a ductile, plastic failure, and showed the ability to absorb a large amount of plastic energy under compressive and tensile loads. Key words: rubberized concrete, concrete properties, compression, durability, failure, modulus of elasticity, slump, tension, toughness, workability.

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