Effects of Salt Corrosion and Freeze-Thaw Cycle on Rubberized Cement-Soil

2010 ◽  
Vol 152-153 ◽  
pp. 967-972
Author(s):  
Feng Chi Wang ◽  
Peng Fei Li ◽  
Xiao Peng Ye
Keyword(s):  
Peak Stress ◽  
Solution Concentration ◽  
Elastic Behavior ◽  
High Concentration ◽  
Rubber Content ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Salt Corrosion ◽  
Freeze Thaw Cycle ◽  
Cement Soil

In order to improve salt corrosion and frost resistance of cement-soil, the waste tire rubber powder was mixed into cement-soil to form rubberized cement-soil. In the salt corrosion and freeze - thaw cycle (SCFT) conditions, compressive strength of rubberized cement-soil increases first and then decreases with rubber content increasing. The more numbers of SCFT cycles, the more strength slip increases. But in high concentration conditions, the strength of rubberized cement-soil with 5%-10% rubber content reduces. With the solution concentration or SCFT cycles number increasing, peak stress of rubberized cement-soil and common cement-soil gradually reduces, but strength slip of rubberized cement-soil is lower than of cement-soil. Studies indicate that the performance of rubberized cement-soil surpasses common cement-soil decided by the relationship between rubberized cement-soil skeleton elastic behavior and coupling expansive force.

Electrical Resistivity of Rubberized Cement-Soil in Formidable Environment

2012 ◽  
Vol 430-432 ◽  
pp. 1606-1609
Author(s):  
Feng Chi Wang ◽  
Yu Zhou ◽  
Man Yuan Zhang ◽  
Xiao Jun Yin
Keyword(s):  
Compressive Strength ◽  
Electrical Resistivity ◽  
Unconfined Compressive Strength ◽  
Dependence Relation ◽  
Rubber Powder ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Salt Corrosion ◽  
Freeze Thaw Cycle ◽  
Cement Soil

Based on experiments of salt corrosion, freeze-thaw cycle and co-action of salt corrosion and freeze-thaw cycle, the electrical resistivity of rubberized cement-soil in formidable natural environment were studied. Under the environment of salt corrosion and freeze-thaw alone, with the increasing of rubber powder content, the electrical resistivity rises at first and then falls down. But under co-action of salt corrosion and freeze-thaw cycle, the electrical resistivity shows descending trend. The electrical resistivity of rubberized cement-soil with No.60 sieve rubber powder is higher than that with No.30 Sieve. The results indicate that there are good linear dependence relation between the electrical resistivity and unconfined compressive strength. For rubberized cement-soil, it is feasible for using electrical resistivity to predict unconfined compressive strength.

scholarly journals Performance Deterioration of Asphalt Mixture under Chloride Salt Erosion

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3339
Author(s):  
Fuyu Wang ◽  
Xingyuan Qin ◽  
Weichen Pang ◽  
Wensheng Wang
Keyword(s):  
Low Temperature ◽  
Salt Solution ◽  
Asphalt Mixture ◽  
Temperature Stability ◽  
Solution Concentration ◽  
Chloride Salt ◽  
High Temperature Stability ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

In order to ensure smooth traffic and driving safety, deicing salt or snow melting agents are usually adopted to solve the problem of traffic jams and prevent pavement surfaces from freezing. The objective of this present study is to investigate the performance deterioration evaluation of asphalt mixture under the chloride salt erosion environment. Five chloride salt solution concentrations were designed and the uniaxial static compression creep test, low-temperature IDT test, freeze-thaw splitting test, and freeze-thaw cycle test were carried out for asphalt mixtures (AC-16) soaked in chloride salt solution. Results showed that with the increase in chloride salt solution concentration, the high-temperature stability, low-temperature crack resistance, and water stability of the asphalt mixture decreases. Moreover, the high-temperature stability, low-temperature crack resistance, and water stability of the asphalt mixture show a decreasing trend under different chloride salt solution concentrations following the negative cubic polynomial function. Based on the viscoelastic analysis, chloride salt solution could reduce the ability of the asphalt mixture to resist instantaneous elastic deformation and permanent deformation, and this influence will become more obvious with the increase in chloride salt solution concentration. In addition, the salt freeze-thaw cycle test indicated that in the early stage of freeze-thaw cycles, the splitting tensile strength of the asphalt mixture decreases rapidly, then tends to be flat, and then decreases rapidly. This study explores the performance damage law of asphalt mixture under salt corrosion, and the analysis results of this study could provide some references for the chloride salt dosage in the snow melting project while spreading deicing salt.

Freezing survival by isolated Malpighian tubules of the New Zealand alpine weta Hemideina maori.

1998 ◽  
Vol 201 (2) ◽  
pp. 227-236 ◽  
Author(s):  
D S Neufeld ◽  
L P Leader
Keyword(s):  
New Zealand ◽  
Membrane Potential ◽  
Basolateral Membrane ◽  
Fluid Secretion ◽  
Malpighian Tubules ◽  
High Concentration ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
High Concentrations

The ability of isolated Malpighian tubules from a freeze-tolerant insect, the New Zealand alpine weta (Hemideina maori), to withstand freezing was assessed by measuring post-freeze membrane potentials and rates of fluid secretion. The hemolymph of cold-acclimated Hemideina maori was found to contain relatively high concentrations of the cryoprotectants trehalose (>300 mmol l-1) and proline (41 mmol l-1). Survival of isolated Malpighian tubules was correspondingly high when a high concentration of trehalose was present in the bathing saline. Tubules allowed to recover for 20 min from a 1 h freeze to -5 degrees C in saline containing 400 mmol l-1 trehalose had a basolateral membrane potential of -53 mV compared with a potential of -63 mV in tubules not exposed to a freeze/thaw cycle. Fluid secretion in tubules that had experienced a freeze/thaw cycle in saline containing 400 mmol l-1 trehalose was 9.9+/-2.6 nl h-1 compared with 18.7+/-5.0 nl h-1 (means +/- s.e.m., N=18) in tubules that had not been frozen. Tubules frozen in saline containing a lower concentration of trehalose (200 mmol l-1) or in glucose (400 mmol l-1) showed a similar ability to survive freezing to -5 degrees C. In contrast, freezing for 1 h at -5 degrees C in saline containing 400 mmol l-1 sucrose produced a 57 % decrease in membrane potential and an 88 % decrease in secretion rate. Tubules held in saline lacking high concentrations of sugars showed no survival after freezing to -5 degrees C for 1 h. When frozen to -15 degrees C, tubules appeared to survive best in saline with the highest trehalose concentration (400 mmol l-1). Freezing damage was not simply the result of exposure to cold, since tubules chilled (unfrozen) to -5 degrees C for 1 h were not compromised even when the bathing saline lacked a high sugar concentration. Exposure of tubules to a combination of low temperature and high osmolality mimicked damage caused by actual freezing: the membrane potential showed a 60 % recovery when the test was performed in saline containing trehalose, but showed no recovery in saline containing sucrose.

Tests and Research on Characteristics of Shear Strength of Cement Improved Soil under Freeze-Thaw Cycle

2014 ◽  
Vol 1015 ◽  
pp. 105-109 ◽  
Author(s):  
An Ping Zhao ◽  
Ai Ping Tang ◽  
Jing Sun ◽  
Xue Mei Yu
Keyword(s):  
Shear Strength ◽  
Traffic Safety ◽  
Frost Damage ◽  
Frozen Soil ◽  
Strong Impact ◽  
Silty Clay ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Cement Soil

Roadbed filling undergo at least one freeze-thaw cycle every year in seasonal frozen soil areas, which will lead subgrade to boiling, settlement, strength weakening etc. and has a strong impact on traffic safety and smooth, need to be solved urgently . In recent years, cement improved soil is applied to dissolve frost damage because it can be obtained locally, and has high performance and low price. However, how to evaluate strength of cement soil under repeated freeze-thaw cycles is the key to its further application in those regions. In the paper, the cement improved silty clay is selected as the object which is most common in Heilongjiang roadbed, many groups of freeze-thaw tests and direct shear tests are conducted at different conditions. From these tests, some conclusions about shear strength index and are obtained: 1. the first freeze-thaw cycle has important effect on cohesion of cement soil, during freeze-thaw cycle, the lower temperature is, the faster is decreasing. 2. decreases with freeze-thaw cycles increase, and there is a peak value existing after the seventh cycle, then reduce rapidly. 3. the internal friction angle appears decreasing – increasing–reducing– increasing trend during cycles but the range of change is little. 4. reduces smaller and increases more when temperature is lower.

scholarly journals Effect of freeze–thaw cycle on physical and mechanical properties and damage characteristics of sandstone

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Longxiao Chen ◽  
Kesheng Li ◽  
Guilei Song ◽  
Deng Zhang ◽  
Chuanxiao Liu
Keyword(s):  
Mechanical Properties ◽  
Shear Failure ◽  
Triaxial Compression ◽  
Physical And Mechanical Properties ◽  
Freeze Thaw ◽  
Damage Characteristics ◽  
Large Pore ◽  
Natural Rock ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

AbstractRock deterioration under freeze–thaw cycles is a concern for in-service tunnel in cold regions. Previous studies focused on the change of rock mechanical properties under unidirectional stress, but the natural rock mass is under three dimensional stresses. This paper investigates influences of the number of freeze–thaw cycle on sandstone under low confining pressure. Twelve sandstone samples were tested subjected to triaxial compression. Additionally, the damage characteristics of sandstone internal microstructure were obtained by using acoustic emission (AE) and mercury intrusion porosimetry. Results indicated that the mechanical properties of sandstone were significantly reduced by freeze–thaw effect. Sandstone’ peak strength and elastic modulus were 7.28–37.96% and 6.38–40.87% less than for the control, respectively. The proportion of super-large pore and large pore in sandstone increased by 19.53–81.19%. We attributed the reduced sandstone’ mechanical properties to the degenerated sandstone microstructure, which, in turn, was associated with increased sandstone macropores. The macroscopic failure pattern of sandstone changed from splitting failure to shear failure with an increasing of freeze–thaw cycles. Moreover, the activity of AE signal increased at each stage, and the cumulative ringing count also showed upward trend with the increase of freeze–thaw number.

Non-linear creep damage model of sandstone under freeze-thaw cycle

2021 ◽  
Vol 28 (3) ◽  
pp. 954-967
Author(s):  
Jie-lin Li ◽  
Long-yin Zhu ◽  
Ke-ping Zhou ◽  
Hui Chen ◽  
Le Gao ◽  
...  
Keyword(s):  
Damage Model ◽  
Creep Damage ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Linear Creep ◽  
Non Linear ◽  
Freeze Thaw Cycle ◽  
Creep Damage Model

scholarly journals Strength and Microscopic Damage Mechanism of Yellow Sandstone with Holes under Freezing and Thawing

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Huren Rong ◽  
Jingyu Gu ◽  
Miren Rong ◽  
Hong Liu ◽  
Jiayao Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Power Function ◽  
Damage Mechanism ◽  
Uniaxial Compression Test ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Microscopic Damage

In order to study the damage characteristics of the yellow sandstone containing pores under the freeze-thaw cycle, the uniaxial compression test of saturated water-stained yellow sandstones with different freeze-thaw cycles was carried out by rock servo press, the microstructure was qualitatively analyzed by Zeiss 508 stereo microscope, and the microdamage mechanism was quantitatively studied by using specific surface area and pore size analyzer. The mechanism of weakening mechanical properties of single-hole yellow sandstone was expounded from the perspective of microstructure. The results show the following. (1) The number of freeze-thaw cycles and single-pore diameter have significant effects on the strength and elastic modulus of the yellow sandstone; the more the freeze-thaw cycles and the larger the pore size, the lower the strength of the yellow sandstone. (2) The damage modes of the yellow sandstone containing pores under the freeze-thaw cycle are divided into five types, and the yellow sandstone with pores is divided into two areas: the periphery of the hole and the distance from the hole; as the number of freeze-thaw cycles increases, different regions show different microscopic damage patterns. (3) The damage degree of yellow sandstone is different with freeze-thaw cycle and pore size. Freeze-thaw not only affects the mechanical properties of yellow sandstone but also accelerates the damage process of pores. (4) The damage of the yellow sandstone by freeze-thaw is logarithmic function, and the damage of the yellow sandstone is a power function. The damage equation of the yellow sandstone with pores under the freezing and thawing is a log-power function nonlinear change law and presents a good correlation.

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