scholarly journals Influence of Freeze-Thaw Cycles on Mechanical Response of Levee Pavement

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shuan Guo ◽  
Zheng Lu ◽  
Guokun Liu ◽  
Baoli Zhuang ◽  
Yongfeng Fan ◽  
...  
Keyword(s):  
Moisture Content ◽  
Mechanical Response ◽  
Triaxial Compression ◽  
Initial Moisture Content ◽  
Dry Density ◽  
Test Results ◽  
Freeze Thaw ◽  
Temperature Range ◽  
Pavement Structure ◽  
The Stability

The freeze-thaw cycles cause deterioration in mechanical properties of levee soil and further endanger the pavement structure on the embankment. This study attempts to comprehensively understand the mechanical response of pavement after freeze-thaw cycles. In this paper, the freeze-thaw cycles test under an open system was carried out, and then the triaxial compression test was conducted. Based on the test results, the effects of freeze-thaw cycles, temperature range, initial dry density, and initial moisture content of embankment soil on the mechanical response of road structure after freeze-thaw were calculated and analyzed. Finally, the stability of the slope of the levee was evaluated. The results show that the number of freeze-thaw cycles has the most significant impact on the mechanical response of pavement, the stress and strain of the structural layers vary in different ranges, and the pavement deflection increases by 5 times after 7 freeze-thaw cycles. However, the initial dry density and initial moisture content of the soil have little influence on the pavement structure, and the temperature range will exert an influence when it exceeds a certain threshold.

Durability of BFRP and Hybrid FRP Sheets under Freeze-Thaw Cycling

2010 ◽  
Vol 163-167 ◽  
pp. 3297-3300 ◽  
Author(s):  
Jia Wei Shi ◽  
Hong Zhu ◽  
Zhi Shen Wu ◽  
Gang Wu
Keyword(s):  
Mechanical Properties ◽  
Test Data ◽  
Mechanical Characteristics ◽  
Test Results ◽  
Freeze Thaw ◽  
Frp Composites ◽  
Test Parameters ◽  
The Stability ◽  
Better Than

Coupon tests were conducted to investigate the mechanical characteristics of basalt FRP (BFRP) sheet, basalt-carbon hybrid FRP sheets and the corresponding epoxy rein under the effect of freeze-thaw cycling. FRP sheets and epoxy rein coupons were subjected to up to 200 and 250 freeze-thaw cycles respectively. Test parameters included the number of freeze-thaw cycles and the types of FRP composites. Test results show that (1) BFRP sheet perform better than CFRP or GFRP sheets under high freeze-thaw cycles; (2) exposed hybrid FRP sheets not only show very little loss in mechanical properties, but also contribute to the stability of test data; (3) mechanical properties of rein epoxy decrease significantly with increasing freeze-thaw cycles.

Influence of interior layer properties to moisture dry-out of CLT walls

2019 ◽  
Vol 46 (11) ◽  
pp. 1001-1009 ◽  
Author(s):  
Villu Kukk ◽  
Annegrete Külaots ◽  
Jaan Kers ◽  
Targo Kalamees
Keyword(s):  
Moisture Content ◽  
Laboratory Test ◽  
Simulation Model ◽  
Initial Moisture Content ◽  
Mineral Wool ◽  
Test Results ◽  
Interior Layer ◽  
Cross Laminated Timber ◽  
Simulation Results ◽  
Dry Out

The objective of this study was to determine the maximum allowable initial moisture content (MC) for cross-laminated timber (CLT) walls having both exterior and interior thermal insulation. A laboratory test was conducted, for which four test walls with two different insulation solutions and two different MCs were built. Based on the test results, a simulation model was configured and simulations using the model were completed. The simulation results determined that the maximum allowable initial MC of the CLT panels was 17% for walls insulated additionally from inside with mineral wool and 15% for CLT wall assemblies insulated with polyisocyanurate (PIR). Based on these results, it was concluded that the allowable MC ranges between 8% and 16% for construction timber, and therefore, using a PIR board as interior insulation for CLT walls should be undertaken with caution given the very small margin for error in MC.

scholarly journals Durability of Structural Lightweight Concrete with Sintered Fly Ash Aggregate

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4565 ◽  
Author(s):  
Lucyna Domagała
Keyword(s):  
Fly Ash ◽  
Moisture Content ◽  
Water Absorption ◽  
Water Permeability ◽  
Lightweight Concrete ◽  
Concrete Strength ◽  
Initial Moisture Content ◽  
Cement Matrix ◽  
Secondary Importance ◽  
Freeze Thaw

The aim of this study was to present the problem of durability of structural lightweight concrete made of a sintered fly ash aggregate. The issue of durability was researched for 12 concrete series in terms of their water absorption, water permeability, and freeze-thaw resistance. Additionally, the microstructure of several concretes was analyzed with a scanning electron microscope (SEM). In the durability research, the influences of the following parameters were taken into consideration: The initial moisture content of sintered fly ash (mc = 0, 17–18, and 24–25%); the aggregate grading (4/8 and 6/12 mm); and the water-cement ratio (w/c = 0.55 and 0.37). As a result of various compositions, the concretes revealed different properties. The density ranged from 1470 to 1920 kg/m3, and the corresponding strength ranged from 25.0 to 83.5 MPa. The durability research results of tested lightweight concretes showed that, despite considerably higher water absorption, a comparable water permeability and comparable or better freeze-thaw resistance in relation to normal-weight concrete may be present. Nevertheless, the fundamental requirement of lightweight concrete to achieve good durability requires the aggregate’s initial moisture content to be limited and a sufficiently tight cement matrix to be selected. The volume share of the cement matrix and aggregate, the cement content, and even the concrete strength are of secondary importance.

Analysis for Influence Factors of Cold Recycling Mixture Compaction Test

2012 ◽  
Vol 204-208 ◽  
pp. 1633-1637
Author(s):  
Yong Bing Wang ◽  
Guo Qiang Ying ◽  
Jian Lin Hu ◽  
Hua Wei Wei ◽  
Qian Zhang
Keyword(s):  
Moisture Content ◽  
Water Absorption ◽  
Base Material ◽  
Optimum Moisture Content ◽  
Dry Density ◽  
Surface Material ◽  
Test Results ◽  
Maximum Dry Density ◽  
Compaction Test ◽  
Recycled Material

In order to study the factors which influence the inorganic binder stabilized material’s compaction test results, different recycled material content therefore different reclaimed gradation mixtures are tested while varying the amount of cement. The experiment results show that contents of the recycled base material and the recycled surface material on the compaction test results are determined by the change of their density and water absorption ratio. Dry density of the recycled mixture increases with the increase of the reclaimed base material density. Low water absorption ratio of the recycled material reduces the reclaimed mixture’s optimum moisture content. Density of the reclaimed wearing surface material reduces the maximum dry density of the reclaimed mixture because the old wearing surface material has lower density. Its low water absorption reduces the optimum moisture content of the recycled mixture. Influence of cement content on compaction test results is the increase of the cement content can enhance the maximum dry density and optimum moisture content of the recycled material. Through the analysis of the results of the compaction test, the key factors in the recycled material compaction test are unveiled.

scholarly journals Study on collapsibility of typical structural loess by multi-parameter comparative analysis

2021 ◽  
Vol 293 ◽  
pp. 01032
Author(s):  
Liu Hongcheng ◽  
Lu Changwei ◽  
Wang Yinxia ◽  
Song Yi ◽  
Guan Xiangfeng ◽  
...  
Keyword(s):  
Particle Size ◽  
Comparative Analysis ◽  
Moisture Content ◽  
Composite Structure ◽  
Structural Parameters ◽  
Initial Moisture Content ◽  
Clay Content ◽  
Dry Density ◽  
Particle Content ◽  
Multiple Groups

To study the collapsibility of typical loess and its influencing factors in different areas, the samples in Jingyang, Lanzhou and Yili were studied. The correlation between initial moisture content, dry density, composition of particle size, structural parameters and the coefficient of subsidence is analyzed. The results show that: the coefficient of collapsibility is negatively correlated with the initial moisture content and dry density. In the experiments of multiple groups, the collapsibility coefficient has a certain correlation with the clay content, but not a uniform correlation with the particle content. The collapse coefficient is approximately positively correlated with the composite structure potential.

scholarly journals Experimental Study on the Effect of Freezing and Thawing on the Shear Strength of the Frozen Soil in Qinghai-Tibet Railway Embankment

2022 ◽  
Vol 2022 ◽  
pp. 1-12
Author(s):  
B. Wang ◽  
J. H. Gao ◽  
Y. Q. Wang ◽  
X. J. Quan ◽  
Y. W. Gong ◽  
...  
Keyword(s):  
Growth Rate ◽  
Internal Friction ◽  
Moisture Content ◽  
Initial Moisture Content ◽  
Friction Angle ◽  
Frozen Soil ◽  
Internal Friction Angle ◽  
Freezing Process ◽  
Dry Density ◽  
Freezing And Thawing

The direct shear tests of different dry density and moisture content samples at different temperatures of the frozen soil in the Qinghai-Tibet Railway embankment between Tanggula South and Anduo section were carried out to analyze the influence rules of each experimental factor on the mechanical properties of frozen soil during the freeze-thaw process. The results show the following. (1) When the frozen soil temperature is below 0°C and continues to drop during the freezing and thawing process, each sample shows the law of a significant increase in cohesion and a slight decrease in the internal friction angle. In the meantime, the cohesion obtained during the thawing process of the sample at the same temperature point is higher than that obtained during the freezing process. In contrast, the internal friction angles exhibit an opposite law, where the internal friction angle during the melting process is lower than the internal friction angle during the freezing process. After freezing-thawing action, it deserves to be mentioned that the cohesion increases slightly while the internal friction angles present a slight decrease trend compared to the initial state. (2) With the decrease in temperature and the gradual increase in cohesion, the temperature curve can be divided into a fast-growing section from 0 to −2°C, a slow-growing section from −2 to −8°C, and a second fast-growing section from −8 to −10°C owing to the combined effect of the pressure-thawing action and ice-water phase change. In addition, the rate of decrease in the internal friction angle also shows a similar pattern. (3) The cohesion and the internal friction angle of samples both tend to increase first and then decrease with the rise of the initial moisture content, and the critical initial moisture content is near the optimal moisture content of 15%. (4) Both the cohesion and the internal friction angle of the samples increase with dry density growth. The growth rate of cohesion will gradually increase as the temperature decreases. Moreover, the growth rate of cohesion of low dry density samples is more susceptible to temperature, while the internal friction angle growth rate is not affected by temperature.

scholarly journals Influence of Freeze-Thaw Cycles on Acoustic Emission Characteristics of Granite Samples under Triaxial Compression

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhandong Su ◽  
Ke Geng ◽  
Fubiao Zhou ◽  
Jinzhong Sun ◽  
Huayan Yu
Keyword(s):  
Acoustic Emission ◽  
Triaxial Compression ◽  
Peak Frequency ◽  
Dominant Frequency ◽  
P Wave ◽  
Cold Regions ◽  
Freeze Thaw ◽  
Ae Signal ◽  
The Stability ◽  
Granite Samples

Understanding the acoustic emission (AE) characteristics of rocks that have undergone freeze-thaw cycling is of great significance for the use of AE technology to monitor the stability of rock masses in cold regions. A series of freeze-thaw cycling experiments and triaxial compression AE tests of granite samples were performed. The results show that, with an increasing number of freeze-thaw cycles, the P-wave velocity and peak AE intensity of granite show a substantial downward trend. The AE ringing counts during triaxial compression can be divided into three stages: abrupt period, calm period, and failure period. The overall change of the characteristic AE signal of granite samples that underwent different freeze-thaw cycles is the same. The AE signal during the destruction of granite occurs in clear dual dominant frequency bands. The peak frequency increases with increasing load time, and this trend becomes less clear as the number of freeze-thaw cycles increases. Overall, the peak frequency distribution tends to change from high to low with an increasing number of freeze-thaw cycles. The results provide basic data for rock mass stability monitoring and prediction, which is of great significance for engineering construction and management in cold regions.

scholarly journals Experimental and Numerical Research on Utilizing Modified Silty Clay and Extruded Polystyrene (XPS) Board as the Subgrade Thermal Insulation Layer in a Seasonally Frozen Region, Northeast China

2019 ◽  
Vol 11 (13) ◽  
pp. 3495 ◽  
Author(s):  
Qinglin Li ◽  
Haibin Wei ◽  
Peilei Zhou ◽  
Yangpeng Zhang ◽  
Leilei Han ◽  
...  
Keyword(s):  
Moisture Content ◽  
Thermal Insulation ◽  
Composite Layer ◽  
Solid Particles ◽  
Dry Density ◽  
Silty Clay ◽  
Insulation Property ◽  
Frost Depth ◽  
The Stability ◽  
Thermal Insulation Property

For strengthening sustainability of subgrade life-cycle service performance and storing industry solid wastes in seasonally frozen regions, compared to previous research of modified silty clay (MC) which consisted of oil shale ash (OSA), fly ash (FA), and silty clay (SC), we identified for the first time, the variations in the thermal insulation capability of MC with different levels of dry density and moisture content. Taking into consideration the effects of 0–20 freeze-thaw (F-T) cycles by a laboratory test, and by the numerical simulation of coupling moisture-temperature, while considering the effects of F-T cycles, the thermal insulation capability of the MC board and the XPS board were studied quantitatively. The testing results show that the thermal conductivity of MC and SC gradually decreases as the number of F-T cycles increases, and that of the XPS board increases with the increased number of F-T cycles, and tend to be of a constant value of 0.061 W/m/K after 17 F-T cycles. The specific heat capacity of the solid particles of the MC, SC, and XPS board does not change regularly as their moisture content, and the number of F-T cycles change, and their variations are in the range of the test error (2%). Simulation results show that MC has the advantage of the thermal insulation property to reduce the frost-depth of 0.21 m, and the thermal insulation property of the composite layer consisting of the MC and XPS board is greater to reduce the frost-depth of 0.55 m, so that it can protect both the SC and sand gravel of the experimental road from the frost heave damage. The research methods and results are very significant in accurately evaluating the thermal insulation capacity and the sustainability of MC and the composite layer consisting of the MC and XPS board, strengthening the stability of the subgrade and increasing the availability of industrial waste.

Influence of Moisture Content to the Freeze-Thaw Performance of Roadbed in High-Cold Areas

2013 ◽  
Vol 442 ◽  
pp. 342-345 ◽  
Author(s):  
Qiao Ling Wu ◽  
Yong Sheng ◽  
Feng Xie
Keyword(s):  
Moisture Content ◽  
Optimum Moisture Content ◽  
Frozen Soil ◽  
Frost Heave ◽  
Document Code ◽  
Freeze Thaw ◽  
Subgrade Soil ◽  
The Common ◽  
Thaw Settlement ◽  
The Stability

Frost-heave and thaw-settlement of roadbed soil in highway will influence directly the durability, safe traffic flow and construction & maintenance costs in high-cold areas, therefore, recognizing and analysing the common embankment technologies of highway roadbed in high-cold areas accurately is significant to the effective controlling of project invest and the highway construction with limited funds in minority areas. The relations of Moisture Content and the freeze-thaw performances of roadbed fillers, subgrade soil were got respectively by experiments, and the results shows: Moisture Content has larger influence on the frost-heave and thaw-settlement performance of the soil. During the embankment of roadbed, the Moisture Content of fillers should be controlled nearby the optimum Moisture Content. The frost-heave and thaw-settlement occurs mainly in the subgrade soil, controlling the Moisture Content of subgrade soil is very important to improve the up-limit of frozen-soil, keep the stability of frozen-soil, control the thaw-settlement of roadbed and get rid of the roadbed diseases. CLC: U416.1 Document code: B

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.

Sign in / Sign up

Export Citation Format

Share Document