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.

Effects of cyclic freezing and thawing on volume changes and permeabilities of soft fine-gained soils

1996 ◽  
Vol 33 (4) ◽  
pp. 529-537 ◽  
Author(s):  
K D Eigenbrod
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Maximum Volume ◽  
Freezing And Thawing ◽  
Volume Changes ◽  
One Dimensional ◽  
Freeze Thaw ◽  
Fine Grained ◽  
Liquidity Index ◽  
Thaw Consolidation

Soft, fine-grained soils were exposed to cyclic one-dimensional, open-system freezing and thawing, resulting in maximum volume changes of up to 30%, depending on the initial moisture content and plasticity of the clay as well as on the rate of freezing. A linear relationship between the net volume changes subsequent to freezing and thawing and the liquidity index prior to freezing and thawing was obtained. This correlation is not unique, but depends on rate and mode of freezing. Thus, settlements from freeze–thaw consolidation in the field can be predicted from such tests if the rate and mode of freezing are the same as in the field. During cyclic freezing and thawing the soils became fissured and jointed, resulting for most clays in large increases in their bulk permeabilities, which increased with an increasing number of freeze–thaw cycles, often by more than two orders of magnitude. For some materials, however, little change in permeability occured. Key words: cyclic freeze–thaw, clays, freeze–thaw consolidation, permeability, volume changes.

Laboratory velocities and attenuation of P‐waves in limestones during freeze‐thaw cycles

Geophysics ◽  
1994 ◽  
Vol 59 (2) ◽  
pp. 245-251 ◽  
Author(s):  
Jean‐Michel Remy ◽  
Michel Bellanger ◽  
Françoise Homand‐Etienne
Keyword(s):  
Hydrostatic Compression ◽  
P Wave ◽  
Compression Tests ◽  
Freezing And Thawing ◽  
P Waves ◽  
Freeze Thaw ◽  
Rock Samples ◽  
Wave Velocities ◽  
P Wave Velocities ◽  
Freezing And Thawing Cycles

The velocity and the attenuation of compressional P‐waves, measured in the laboratory at ultrasonic frequencies during a series of freezing and thawing cycles, are used as a method for predicting frost damage in a bedded limestone. Pulse transmission and spectral ratio techniques are used to determine the P‐wave velocities and the attenuation values relative to an aluminum reference sample with very low attenuation. Limestone samples were water saturated under vacuum conditions, jacketed with rubber sleeves, and immersed in an antifreeze bath (50 percent methanol solution). They were submitted to repeated 24-hour freezing and thawing cycles simulating natural environment conditions. During the freeze/thaw cycles, P‐wave velocities and quality factor Q diminished rapidly in thawed rock samples, indicating modification of the pore space. Measurements of crack porosity were conducted by hydrostatic compression tests on cubic rock samples that had been submitted to these freeze/thaw cycles. These measurements are used as an index of crack formation. The hydrostatic compression tests confirmed the phases of rock damage that were shown by changes in the value of Q. Furthermore, comparisons between Q values and crack porosity demonstrated that the variations of P‐wave attenuation are caused by the creation of new cracks and not by the enlargement of pre‐existing cracks.

Prediction for Relative Dynamic Elastic Modulus of PVA-ECC under Freezing and Thawing Cycles

2010 ◽  
Vol 44-47 ◽  
pp. 3893-3896
Author(s):  
Hui Fang Hou ◽  
Shu Guang Liu ◽  
Chang Wang Yan ◽  
Jian Wen Bai
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Elastic Modulus ◽  
Dynamic Elastic Modulus ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Method Optimization ◽  
Artificial Neural ◽  
Hidden Layer ◽  
Freezing And Thawing Cycles

This study focuses on the relative dynamic elastic modulus of the polyvinyl alcohol fiber reinforced cementitious composite (PVA-ECC) after three hundred freeze-thaw cycles. The Artificial Neural Network of freeze-thaw cycles prediction was finally established through data analysis with the help of BP artificial neural network, calculation method optimization and sample training, many times’ trails of the hidden layer and every hidden unit, and the optimal selection of the training function. The results show that there is a small relative error between the predicted value and the actual one of the specimen of the relative dynamic elastic modulus of the PVA-ECC, and the established artificial neural network model bears a higher prediction precision.

scholarly journals Fatigue Characteristics of Prestressed Concrete Beam under Freezing and Thawing Cycles

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yuanxun Zheng ◽  
Lei Yang ◽  
Pan Guo ◽  
Peibing Yang
Keyword(s):  
Fatigue Life ◽  
Prestressed Concrete ◽  
Life Prediction ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Prestressed Concrete Beam ◽  
Fatigue Characteristics ◽  
Freezing And Thawing Cycles

In order to reveal the influence of freezing and thawing on fatigue properties of the prestressed concrete beam, a kind of novel freeze-thaw test method for large concrete structure components was proposed, and the freeze-thaw experiments and fatigue failure test of prestressed concrete hollow beams were performed in this paper. Firstly, the compressive strength and dynamic elastic modulus of standard specimens subjected to different numbers of freeze-thaw cycles (0, 50, 75, and 100) were determined. Then, the static and dynamic experiments were performed for prestressed concrete beams under different freeze-thaw cycles. Depending on the static failure test results, the fatigue load for the prestressed concrete beam model was carried out, the fatigue tests for prestressed concrete beam under freezing and thawing cycles were done, and the influence of fatigue loading times on dynamic and static characteristics of prestressed concrete beam was also studied. Finally, the relation between fatigue characteristics and numbers of freeze-thaw cycles was established, and the fatigue life prediction formulas of prestressed concrete beams under freeze-thaw cycles were developed. The research shows that the freezing and thawing cycles had obvious influence on fatigue life, and the freezing and thawing cycles should be taken into account for life prediction and quality evaluation of prestressed concrete beams.

Dependence of Relative Decreasing in Strength by Rate of Strain for the New Rapid Method for Determination of Concrete Frost Resistance

2015 ◽  
Vol 725-726 ◽  
pp. 505-510
Author(s):  
Olga Pertseva ◽  
Sergey Nikolskiy
Keyword(s):  
Tensile Strength ◽  
Rapid Method ◽  
Frost Resistance ◽  
New Method ◽  
Basic Method ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Freezing And Thawing Cycles ◽  
Non Destructive

The task of the project is obtaining the dependence between the relative decreasing of strength and rate of strain and substantiation of the new method for determination of concrete frost resistance. It has been analytically proved that using concrete’s rate of strain ε as a measure of damage, instead of decreasing of tensile strength R, increases freeze-thaw resistance’s accuracy of estimation a lot under otherwise equal conditions by the time of freeze-thaw cycling. Also it has been experimentally shown that ratio of relative decreasing R to ε in direction, perpendicular to compression, is assumed to be independent on values R and ε for a given concrete and on the ways of achieving them during mechanical or freeze-thaw cycling. To determine the dependence δR/R by ε (z) 8 specimens were tested by non-destructive method (RU 2 490 631) and two baths of 50 specimens by basic method (thermo cycling). Results of the non-destructive method are different from results by basic method for 6,3%. Dependence of relative decreasing in strength by rate of strain is near to linear and, therefore, value of z is constant. Taking this into account patented methods for estimation of concrete’s freeze-thaw resistance as per values R and ε received after freezing and thawing cycles of some specimens and their postlimenary failure by linear compression was substantiated.

scholarly journals Freezing and thawing cycles affect nitrous oxide emissions in rain-fed lucerne (Medicago sativa) grasslands of different ages

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12216
Author(s):  
Yuan Li ◽  
Yuying Shen ◽  
Tao Wang
Keyword(s):  
Soil Temperature ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Depth ◽  
Denitrifying Bacteria ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Soil Microbial ◽  
Freezing And Thawing Cycles

Lucerne (Medicago sativa L.) is a major component of the crops used in dry-land farming systems in China and its management is associated with notable nitrous oxide (N2O) emissions. A high proportion of these emissions is more likely to occur during periods when the soil undergoes freezing and thawing cycles. In this study, the effects of freeze/thaw cycles on N2O emissions and related factors were investigated in lucerne grasslands. The hypothesis was tested whether increased emissions resulted from a disruption of nitrification or denitrification caused by variations in soil temperatures and water contents. Three days (3 × 24 h) were chosen, where conditions represented freezing and thawing cycles. N2O emissions were measured for a fallow control (F) and two grasslands where lucerne had been cultivated for 4 and 11 years. Soil temperature, soil water content, soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN), soil ammonium nitrogen (NH4+-N), and soil nitrate nitrogen (NO3−-N) contents were measured. Moreover, the quantities of soil nitrification and denitrification microbes were assessed. Variations in N2O emissions were strongly affected by freeze/thaw cycles, and emissions of 0.0287 ± 0.0009, 0.0230 ± 0.0019, and 0.3522 ± 0.0029 mg m−2 h−1 were found for fallow, 4-year-old, and 11-year-old grasslands, respectively. Pearson correlation analyses indicated that N2O emissions were significantly correlated with the soil water content, temperature, NH4+-N content, and the number of nitrosobacteria and denitrifying bacteria at a soil depth of 0–100 mm. The numbers of nitrosobacteria and denitrifying bacteria correlated significantly with soil temperature at this soil depth. MBN and soil NH4+-N contents correlated significantly with soil water content at this depth. Principal component analysis highlighted the positive effects of the number of denitrifying bacteria on N2O emissions during the freeze/thaw period. Furthermore, soil temperature and the number of nitrosobacteria at the tested soil depth (0−100 mm) also played a significant role. This shows that soil freeze/thaw cycles strongly impacted both N2O emissions and the diurnal range, and the number of denitrifying bacteria was mainly influenced by soil temperature and soil NH4+-N content. The number of denitrifying bacteria was the dominant variable affecting N2O emissions from lucerne grasslands during the assessed soil freeze/thaw period on the Loess Plateau, China.

scholarly journals Rehabilitation of buildings in winter conditions

2011 ◽  
Vol 9 (3) ◽  
pp. 357-366
Author(s):  
Slavko Zdravkovic ◽  
Dragoslav Stojic ◽  
Dragana Turnic
Keyword(s):  
Water Absorption ◽  
Porous Materials ◽  
Hardened Concrete ◽  
Freezing And Thawing ◽  
Volume Changes ◽  
Winter Conditions ◽  
Volume Measure ◽  
Solidification Processes ◽  
Freezing And Thawing Cycles

Various factors are taken as the criteria for determining the susceptibility of materials to frost, such as: porosity and water absorption, volume changes, the number of freezing and thawing cycles. Mortars as a mixture of binder, water and sand, after placing and undergoing bonding and solidification processes, represent extremely porous materials, and the same holds for concrete. When the water turns into ice, it changes its volume measure unit from (V?) into Vt = 1.09 V?. If the concrete that has not completed bonding is exposed to frost, the process is likely to be suspended, and later when the warming starts, followed by the thawing of concrete, it will need the repeated vibrating in order to bind again and harden up without the detrimental effects on its strength. However, there are cases of devastating effects of frost on the hardened concrete. All the mentioned strategies should be kept in mind when performing remediation.

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 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.

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.

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