Hydraulic and strength properties of unexposed and freeze–thaw exposed cement-stabilized soils

2015 ◽  
Vol 52 (3) ◽  
pp. 283-294 ◽  
Author(s):  
Reza Jolous Jamshidi ◽  
Craig B. Lake
Keyword(s):  
Compressive Strength ◽  
Hydraulic Conductivity ◽  
Water Content ◽  
Healing Process ◽  
Hydraulic Performance ◽  
Test Method ◽  
Mix Design ◽  
Conductivity Measurements ◽  
Strength Performance ◽  
Freeze Thaw

A total of 108 specimens were prepared to examine the hydraulic performance and strength performance of nine different cement-stabilized soils under unexposed and freeze–thaw exposed conditions. Specimens from each mix design were evaluated under two levels of curing conditions (i.e., immature versus mature). Hydraulic conductivity and unconfined compressive strength (UCS) measurements were performed to assess changes in the performance of specimens after 12 cycles of freezing at −10 ± 1 °C and thawing at 22 ± 1 °C. Measured mass losses of the specimens from a standard brushing test were also monitored at different freeze–thaw cycles, and results were compared with the changes in the hydraulic performance for each mix design. Hydraulic conductivity measurements on unexposed mature specimens showed that the lowest values likely occurred at water contents slightly wet of optimum water content (OWC). The UCS values showed a general decreasing trend with the increase in the water content for both immature and mature specimens under unexposed conditions. After freeze–thaw exposure, specimens showed minor reductions as well as increases of up to 5250 times in hydraulic conductivity values. Increases of up to 14% and reductions of up to 58% in compressive strength were also observed, compared with unexposed conditions. For most cases, mature specimens resulted in a higher degree of damage compared with immature specimens. Results from the brushing tests showed this test method is not a suitable indicator for predicting changes in the hydraulic performance of cement-stabilized soils. Hydraulic conductivity measurements after a period of post-exposure healing showed damaged specimens have some potential in recovering parts of the increased hydraulic conductivity value due to the healing process.

Assessment of clogging in constructed wetlands by saturated hydraulic conductivity measurements

2019 ◽  
Vol 79 (2) ◽  
pp. 314-322 ◽  
Author(s):  
F. Licciardello ◽  
R. Aiello ◽  
V. Alagna ◽  
M. Iovino ◽  
D. Ventura ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Hydraulic Conductivity ◽  
Constructed Wetlands ◽  
Spatial Scales ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Test Method ◽  
Conductivity Measurements ◽  
Multiple Spatial Scales ◽  
Ks Values

Abstract This study aims at defining a methodology to evaluate Ks reductions of gravel material constituting constructed wetland (CW) bed matrices. Several schemes and equations for the Lefranc's test were compared by using different gravel sizes and at multiple spatial scales. The falling-head test method was implemented by using two steel permeameters: one impervious (IMP) and one pervious (P) on one side. At laboratory scale, mean K values for a small size gravel (8–15 × 10−2 m) measured by the IMP and the P permeameters were equal to 19,466 m/d and 30,662 m/d, respectively. Mean Ks values for a big size gravel (10–25 × 10−2 m) measured by the IMP and the P permeameters were equal to 12,135 m/d and 20,866 m/d, respectively. Comparison of Ks values obtained by the two permeameters at laboratory scale as well as a sensitivity analysis and a calibration, lead to the modification of the standpipe equation, to evaluate also the temporal variation of the horizontal Ks. In particular, both permeameters allow the evaluation of the Ks decreasing after 4 years-operation and 1–1.5 years' operation of the plants at full scale (filled with the small size gravel) and at pilot scale (filled with the big size gravel), respectively.

A constant-head pumping test method using direct-push equipment for in situ hydraulic conductivity measurements

Géotechnique ◽  
2012 ◽  
Vol 62 (3) ◽  
pp. 253-262 ◽  
Author(s):  
T. KOBAYASHI ◽  
H. ONOUE ◽  
S. OBA ◽  
N. YASUFUKU ◽  
K. OMINE
Keyword(s):  
Hydraulic Conductivity ◽  
Pumping Test ◽  
Test Method ◽  
Conductivity Measurements ◽  
Direct Push ◽  
Constant Head

scholarly journals The impacts of freeze–thaw cycles on saturated hydraulic conductivity and microstructure of saline–alkali soils

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenshuo Xu ◽  
Kesheng Li ◽  
Longxiao Chen ◽  
Weihang Kong ◽  
Chuanxiao Liu
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Water Content ◽  
Size Distribution ◽  
Saturated Hydraulic Conductivity ◽  
High Water Content ◽  
Soil Permeability ◽  
Freeze Thaw ◽  
Alkali Soil

AbstractStudy on the microscopic structure of saline–alkali soil can reveal the change of its permeability more deeply. In this paper, the relationship between permeability and microstructure of saline–alkali soil with different dry densities and water content in the floodplain of southwestern Shandong Province was studied through freeze–thaw cycles. A comprehensive analysis of soil samples was conducted using particle-size distribution, X-ray diffraction, freeze–thaw cycles test, saturated hydraulic conductivity test and mercury intrusion porosimetry. The poor microstructure of soil is the main factor that leads to the category of micro-permeable soil. The porosity of the local soil was only 6.19–11.51%, and ultra-micropores (< 0.05 μm) and micropores (0.05–2 μm) dominated the pore size distribution. Soil saturated water conductivity was closely related to its microscopic pore size distribution. As the F–T cycles progressed, soil permeability became stronger, with the reason the pore size distribution curve began to shift to the small pores (2–10 μm) and mesopores (10–20 μm), and this effect was the most severe when the freeze–thaw cycle was 15 times. High water content could promote the effects of freeze–thaw cycles on soil permeability and pore size distribution, while the increase of dry density could inhibit these effects. The results of this study provide a theoretical basis for the remediation of saline–alkali soil in the flooded area of Southwest Shandong.

Influence of Recycled Concrete Powder (RCP) and Recycled Brick Powder (RBP) on the Physical/Mechanical Properties and Durability of Raw Soil

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1475
Author(s):  
Li’an Zhou ◽  
Yang Liu ◽  
Jiacheng Lu ◽  
Wenjuan Zhou ◽  
Hui Wang
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Recycled Concrete ◽  
Dry Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Freeze Thaw ◽  
Performance Change ◽  
Brick Powder ◽  
Research Findings

The influence of recycled concrete powder (RCP) and recycled brick powder (RBP) on the dry density, optimal water content, and compressive strength of raw soil materials was investigated in this study. Moreover, the following resistance of freeze–thaw cycles was also considered. Additionally, X-ray diffraction (XRD) and scanning electron microscope (SEM) were selected to detect its mineral composition and observe the microstructure, further revealing the mechanism of performance change. The mass ratios of recycled concrete powder and recycled brick powder were 2% ~ 14%. Results showed that the dry density decreased and the optimal water content increased with the increasing dosage of recycled concrete powder and recycled brick powder. When the dosage of RCP or RBP was lower than 14%, raw soil with RCP showed higher optimal water content and lower dry density. However, when the dosage was higher than 14%, the result was the opposite. The addition of recycled concrete powder and recycled brick powder was able to decrease the compressive strength of raw soil, except for 10% of recycled brick powder. Raw soil with recycled brick powder presented higher compressive strength than that of raw soil with recycled concrete powder. RBP could improve the freeze–thaw cycles’ resistance of specimens; however, RCP led to decreasing the resistance of freeze–thaw cycles. These research findings can provide reference to the recycling of construction waste.

scholarly journals Freezing–Thawing Behavior of Lime Treated Fine–grained Soil

2018 ◽  
Vol 7 (4) ◽  
pp. 75
Author(s):  
Abdulrahman Aldaood ◽  
Amina Khalil ◽  
Marwen Bouasker ◽  
Muzahim Al-Mukhtar
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Unconfined Compressive Strength ◽  
Soil Samples ◽  
Treated Soil ◽  
Freeze Thaw ◽  
Fine Grained ◽  
Mineralogical Properties ◽  
Fine Grained Soil ◽  
The Impact

This research study was carried out to investigate the impact of freeze-thaw cycles on the mechanical and the mineralogical properties of lime treated fine-grained soil. The unconfined compressive strength, wave velocity, volume change, water content, pH and electrical conductivity values were determined during freeze-thaw cycles. Furthermore, Mercury porosimetry and X-ray diffraction tests were carry out to determine changes at microscopic level. The soil used in this study was taken at a site near Jossigny region in eastern part of Paris–France. The soil samples were treated with optimum lime percent 3% depending on the pH method, then cured for 28 days at 20 °C. The soil samples were subjected to 12 cycles of freeze-thaw following ASTM procedure.    The result referred that, natural soil exhibit no strength resistance against freeze-thaw cycles and failed during the first hours of freeze-thaw cycles. Analyses indicated that freeze-thaw cycles reduce the unconfined compressive strength of all the tested samples. Moreover, water content during the applied cycles increases and induces significant volume changes. During freeze-thaw cycles, the cracks propagation which caused by the formation of ice lenses in the pores of lime treated soil samples were consider to have significant. The changes in the micro-structural and mineralogical properties reduce the durability  of the lime treated soil samples when subjected to freeze-thaw cycles.

Recycled Aggregate Performance Experiment Study on Basis of Saturated Surface Dried Crush Value Index

2011 ◽  
Vol 374-377 ◽  
pp. 1641-1645
Author(s):  
Bo Zhang ◽  
She Liang Wang ◽  
Yuan Fang Du ◽  
Long Ping Jing
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Test Method ◽  
Recycled Aggregate ◽  
Concrete Compressive Strength ◽  
Strength Performance ◽  
Ordinary Concrete ◽  
Limit Value ◽  
Experiment Analysis ◽  
Key Parameter

Crush value index is a key parameter for measurement of coarse aggregate strength performance. In this paper the eight group of crush value index are tested for the recycled aggregate used of waste concrete which is gathered from three different remove construction plants. The experiment analysis result is shown that the crush value of recycled aggregate is greater 2.5 times than natural aggregate. Meanwhile, compared with air dried condition, the crush value index of saturated face dried condition is from 7.22% to18.2%. Furthermore the recycled aggregate can be suitable to make concrete requirement which compression strength grade is C35 and lower than C35 in China. In the experiment, comparative analysis is found that the RA-10 aggregate compressive strength is slightly from 2.06% to 8.7%. Those which are higher limit value of standard for test method of mechanical properties on ordinary concrete and the divergence are less than 10%. Consequently the recycled aggregate can be used for concrete, and its compressive strength is also fundamentally satisfied for requirement of concrete compressive strength.

scholarly journals The Impacts of Freeze-thaw Cycles on Saturated Hydraulic Conductivity and Microstructure of Saline-alkali Soils

2021 ◽  
Author(s):  
Wenshuo Xu ◽  
Kesheng Li ◽  
Longxiao Chen ◽  
Weihang Kong ◽  
Chuanxiao Liu
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Water Content ◽  
Size Distribution ◽  
Soil Permeability ◽  
Freeze Thaw ◽  
Alkali Soil ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

Abstract Study on the microscopic structure of saline-alkali soil can reveal the change of its permeability more deeply. In this paper, the relationship between permeability and microstructure of saline-alkali soil with different dry densities and water content in the floodplain of southwestern Shandong Province was studied through freeze-thaw cycles. A comprehensive analysis of soil samples was conducted using particle-size distribution, X-Ray diffraction, Freeze-Thaw cycle test, saturated hydraulic conductivity test and mercury intrusion porosimetry. The poor microstructure of soil is the main factor that leads to the category of micro-permeable soil. The porosity of the local soil was only 6.19–11.51%, and ultra-micropores (< 0.05 µm) and micropores (0.05-2 µm) dominated the pore size distribution. Soil saturated water conductivity was closely related to its microscopic pore size distribution. As the F-T cycles progressed, soil permeability became stronger, with the reason the pore size distribution curve began to shift to the small pores (2–10 µm) and mesopores (10–20 µm), and this effect was the most severe when the freeze-thaw cycle was 15 times. High water content could promote the effects of freeze-thaw cycles on soil permeability and pore size distribution, while the increase of dry density could inhibit these effects. The results of this study provide a theoretical basis for the remediation of saline-alkali soil in the flooded area of Southwest Shandong.

Experimental Study of Compression and Carbonation in Concrete Subjected to Freeze-Thaw Environment

2014 ◽  
Vol 887-888 ◽  
pp. 814-818
Author(s):  
Li Xue Wang ◽  
Xiao Ting Shan ◽  
Yu Qing Zhang ◽  
Chun Sheng Li ◽  
Zai Xing Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Test Method ◽  
Carbonation Depth ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw ◽  
Concrete Properties

In order to research the changes of concrete properties in freeze-thaw environment, five concrete samples with water-cement ratio respectively equal to 0.60, 0.65, 0.70, 0.75 and 0.80 were tested in freeze-thaw environment according to GB/T50082-2009 concrete rapid freeze-thaw cycles test method. Five samples were carried out 0, 25, 50, 75, 100 times faster freeze-thaw cycles test. With the increasing number of freeze-thaw cycles, the concrete relative dynamic modulus of elasticity loss rises, the compressive strength drops, and the carbonation depth increases. The greater the water-cement ratio of concrete specimens with freeze-thaw cycles, the greater the degree of damage increases.

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